document_title: Google Chrome version history

question_text: what is the most current version of chrome for mac

text: Google Chrome version history

text: The following table summarizes the release history for the Google Chrome web browser.

text:
Discontinued

Stable channel

Beta channel

Dev channel

Canary channel

text:
Major version

Release date

Layout engine[r 1]

V8 engine[r 2]

Significant changes

0.2.149

2008-09-02

WebKit 522

0.3

First release[r 3]

0.3.154

2008-10-29

Improved plugin performance and reliability
Spell checking for input fields
Improved web proxy performance and reliability
Tab and window management updates

0.4.154

2008-11-24

WebKit 525

Bookmark manager with import and export support
Privacy section added to the application options
New blocked popup notification

1.0.154

2008-12-11

WebKit 528

First stable release

2.0.172

2009-05-24

WebKit 530

0.4

35% faster JavaScript on the SunSpider benchmark
Mouse wheel support
Full-screen mode
Full-page zoom
Form auto-fill
Sort bookmarks by title
Tab docking to browser and desktop edges
Basic Greasemonkey support[r 4]

3.0.195

2009-10-12

WebKit 532

1.2

New "new tab" page for improved customization
25% faster JavaScript
HTML5 video and audio tag support
Lightweight theming

4.0.249

2010-01-25

WebKit 532.5

1.3

Extensions
Bookmark synchronization
Enhanced developer tools
Improved HTML5 support
Performance improvements
Full ACID3 pass
HTTP byte range support
Experimental new anti-reflected-XSS feature called "XSS Auditor"[r 5]

4.1.249

2010-03-17

Translate infobar[clarification needed]
New privacy features
Disabled XSS Auditor[r 6]

5.0.375

2010-05-21

WebKit 533

2.1

Browser preference synchronizing
Increased HTML5 support (Geolocation API, App Cache, web sockets, and file drag-and-drop)
Revamped bookmark manager
Adobe Flash Player integrated[r 7][r 8]
First stable releases for macOS, 32 bit Linux, and 64 bit Linux[r 9]

6.0.472

2010-09-02

WebKit 534.3

2.2

Updated and more streamlined UI with simplified Omnibox
New tab page
Merged menu buttons
Form auto-fill
Expanded synchronization support to include extensions and auto-fill data
Support for WebM videos
Built-in PDF support (disabled by default)[r 10]

7.0.517

2010-10-21

WebKit 534.7

2.3.11

Implemented HTML5 parsing algorithm
File API
Directory upload via input tag
macOS version gained AppleScript support for UI automation[r 11]
Late binding enabled for SSL sockets: high priority SSL requests are now always sent to the server first.
New options for managing cookies
Updated New Tab page to enable featuring of web applications

8.0.552

2010-12-02

WebKit 534.10

2.4.9

Chrome Web Store
Built-in PDF viewer that works inside Chrome's sandbox for increased security
Expanded synchronization support to include web applications
Improved plug-in handling[r 12]
This release added "about:flags" to showcase experimental features such as Chrome Instant, side tabs on Windows, tabbed settings, Click to Play,[clarification needed] background web applications, Remoting,[clarification needed] disables outdated plug-ins,[clarification needed] XSS Auditor,[clarification needed] Cloud Print Proxy,[clarification needed] GPU-accelerated compositing, WebGL support for the canvas element, and a "tab overview" mode (like Exposé) for macOS.

9.0.597

2011-02-03

WebKit 534.13

2.5.9

WebGL enabled by default
Adobe Flash sandboxing on Windows and Chrome Instant (a la Google Instant) option[r 13]
WebP support[r 14]
New flags: print preview, GPU-accelerated compositing, GPU-accelerated Canvas 2D, Google Native Client, CRX-less Web Apps, Web page prerendering, experimental Extension APIs, disable hyperlink auditing

10.0.648

2011-03-08

WebKit 534.16

3.0.12

Google Cloud Print sign-in interface enabled by default
Partially implemented sandboxing of the GPU process[r 15][r 16]
Faster JavaScript performance due to incorporation of Crankshaft, an improved compiler for V8[r 17]
Settings pages that open in a tab, rather than a dialog box
Malware reporting and disabling outdated plugins
Password sync
GPU accelerated video
Background WebApps
webNavigation extension API[r 18]

11.0.696

2011-04-27

WebKit 534.24

3.1.8

HTML5 Speech Input API[r 19]
Updated icon[r 20]

12.0.742

2011-06-07

WebKit 534.30

3.2.10

Hardware accelerated 3D CSS
New Safe Browsing protection against downloading malicious files
Ability to delete Flash cookies from inside Chrome[r 21]
Launch Apps by name from the Omnibox
Integrated Sync into new settings pages
Improved screen reader support
New warning when hitting Command-Q on Mac[r 21]
New flags: P2P API
Existing tab on foreground on open
Experimental new tab page
Add grouping to tab context menu
Run PPAPI Flash in the renderer process
Multiple profiles
Removed Google Gears
Print and Save buttons in the PDF viewer[r 22]

13.0.782

2011-08-02

WebKit 535.1

3.3.10

Instant Pages (pre-rendering of Web pages)[r 23]
Native print interface and preview (Linux and Windows only)
Experimental new tab page
Experimental Restrict Instant To Search option

14.0.835

2011-09-16

3.4.14

Native Client (NaCl) enabled for apps in the Chrome Web Store[r 24]
Web Audio API
Additional macOS Lion feature support
Sync Encryption for all data
Print preview on Mac
Validation of HTTPS sites[r 25]
Experimental Web Request extension API
Experimental Content Settings extension API[r 26]

15.0.874

2011-10-25

WebKit 535.2

3.5.10

Faster print preview[r 27]
Redesigned new tab page on by default[r 27]
JavaScript fullscreen API enabled by default[r 27]
Inline installation of Chrome Web Store items by verified sites
Omnibox History synchronization[r 28]
Switched to FFmpeg native VP8 decoder[r 29]
Extensions integrated into settings pages
GPU Accelerated Canvas 2D disabled

16.0.912

2011-12-13

WebKit 535.7

3.6.6

Multiple profiles on by default[r 28]
Optional permissions in Chrome extensions, so the user can opt-in or opt-out of the optional permissions at installation time[r 30]
Experimental support for side tabs was removed.[r 31]

17.0.963

2012-02-08

WebKit 535.11

3.7.12

Updated Omnibox prerendering of pages[r 32]
Download scanning protection[r 32]
New extensions APIs[r 32]
Improved History tab
Removal of "+" symbol from the "new tab" button
Limited support for changing user agent strings
Adjustable margins in print preview[r 33]
Search engine synchronization[r 34]
Disabled GAIA profile info[r 35]

18.0.1025

2012-03-282012-06-27 (Android ARM)2012-09-26 (18.0.1026, Android x86)

WebKit 535.19

3.8.9

Hardware-accelerated Canvas2D graphics[r 36]
WebGL without the need of 3D graphics hardware through the software rasterizer SwiftShader[r 36]
Brighter "new tab" button[r 37]

19.0.1084

2012-05-152012-06-28 (iOS)

WebKit 536.5

3.9.24

Access tabs between devices[r 38]
Reorganized and searchable settings interface
Better spell check by using the Google search engine spell checker
Web Store link to the bottom of New Tab page
Experimental JavaScript Harmony (ECMAScript 6) support[r 39]
Experimental Web Intents API[r 40]

20.0.1132

2012-06-26

WebKit 536.10

3.10.6

Experimental touch friendly user interface adjustments. Context menus have extra vertical padding between items.[r 41]
New tab button is bigger and wider

21.0.1180

2012-07-312012-08-22 (iOS)

WebKit 537.1

3.11.10

Media Stream API (getUserMedia) enabled by default. (E.g. webcam access via JavaScript.)[r 42]
Gamepad API prototype available by default.
Support for (pointer) and (hover) CSS media queries so sites can optimize their user interface for touch when touch-screen support is available.
HTML5 audio/video and WebAudio now support 24-bit PCM wave files

22.0.1229

2012-09-25

WebKit 537.4

3.12.19

New-style packaged apps are enabled by default.
New menu icon, replacing the wrench icon
Support for TLS 1.1[r 43][r 44]
Support for color management ICC v2 profiles by default[r 45]

23.0.1271

2012-11-062012-11-28 (iOS)

WebKit 537.11

3.13.7

Do Not Track preference[r 46]
Hardware video acceleration with 25% more efficient power consumption in some scenarios
Manager for site permission control
New icon for Chrome Web Store when opening new tab
PPAPI Flash Player (or Pepper-based Flash Player) replaced the NPAPI Flash Player on Mac also[r 47]

24.0.1312

2013-01-10

WebKit 537.17

3.14.5

Support for MathML[r 48]
The HTML5 datalist element now supports suggesting a date and time[r 48]
Experimental support for CSS custom filters[r 48][r 49]

25.0.1364

2013-02-212013-02-27 (Android)2013-03-04 (iOS)

WebKit 537.22

3.15.11

Support for Opus audio
Support for VP9 video[r 50]
Silent installs of external extensions are now disabled by default.[r 51]
Web Speech API[r 52]
Encrypted omnibox search (https)[r 53]
Native Client on ARM
Disabled MathML support for the time being[r 54]
Android version (update from 18):

Newer V8 JavaScript engine
Audio now continues to play while Chrome is in the background
Support for pausing audio in Chrome when phone is in use

26.0.1410

2013-03-262013-04-03 (Android)2013-04-09 (iOS)

WebKit 537.31

3.16.14

Improved spell checker (grammar and homonym checking)[r 55]
Desktop shortcuts for multiple users (profiles) on Windows[r 55]
Asynchronous DNS resolver on Mac and Linux[r 55]
Android version:[r 56]

Autofill and password sync
Performance and stability improvements

27.0.1453

2013-05-212013-05-22 (Android)2013-06-03 (iOS)

WebKit 537.36

3.17.6

Resource handling optimized for faster page loads[r 57]
Improved Omnibox predictions and spelling correction[r 57]
syncFileSystem API for Google Drive data synchronization[r 57]
Stop packaging Manifest version 1.0 extensions[r 58]
Android version:[r 59]

Fullscreen on phones (scrolling down the page makes the toolbar disappear)
Simpler searching (the query stays visible in the omnibox, making it easier to edit)
Client-side certificate support
Tab history on tablets
"A ton of stability and performance fixes"

28.0.1500

2013-06-17 (Linux)2013-07-09 (macOS and Windows)2013-07-10 (Android)2013-07-17 (iOS)

Blink 537.36WebKit 537.36 (on iOS)

3.18.5

Replaced layout engine with Blink, a fork of WebKit[r 60][r 61][r 62] on all platforms besides iOS
Faster page loads with the new Blink threaded HTML parser[r 63]
Rich Notifications and Notification Center (HTML-based notifications deprecated)[r 64]
Major improvements to the asm.js benchmark performances[r 63]
Support for the CSS :unresolved pseudoclass for Custom Elements[r 63]
Support for the CSS @supports conditional blocks to test for property:value pairs[r 63]
Android version:

Fullscreen API support (fullscreen browsing on tablets)[r 63]
Experimental WebGL, Web Audio, WebRTC support behind flags[r 63]
Built-in translation[r 65]
iOS version:

Improved interoperability with many other Google Apps[r 66]
Voice Search enhancements[r 66]
Fullscreen for iPad[r 66]
Data usage savings (rolling out over time)[r 66]
Access to browser history[r 66]

29.0.1547

2013-08-20 (Linux, macOS and Windows)2013-08-21 (Android)2013-09-12 (iOS)

Blink 537.36

3.19.18

Support for VP9 final
Support for TLS 1.2
Preliminary QUIC support[r 67]
Improved Omnibox suggestions based on the recency of visited sites
Ability to reset user profile back to its original state
New apps and extensions APIs (such as Native Messaging API for connecting Chrome with native applications installed on the same computer - an alternative to NPAPI[r 68])
Android version:

WebRTC support[r 69]
WebAudio support[r 69]
Improved scrolling responsiveness[r 70] and visual indication when scrolling to the top or bottom of a page[r 69]
Startup performance and stability improvements[r 70]
New color picker user interface for web forms[r 69]
Support for Google's experimental data compression service (comparable to Opera Turbo) that lets Google servers quickly read and optimize a Web page for mobile devices, then transmit it to the smartphone using Google's SPDY network technology.
Rudimentary tab groups implemented
iOS version:

Get back to Search Results faster
Data cost savings enhancements (rolled out incrementally)
Voice search pronoun support (e.g. queries like: “Who is the president of the United States?” followed by “Who is his wife?”)
Improvements to Single Sign On with other Google Apps[r 71]
Support for WebP image format[r 72]

30.0.1599

2013-09-18 (iOS)2013-10-01 (Linux, macOS and Windows)2013-10-02 (Android)

Blink 537.36

3.20.17

New image context menu item: "Search Google for this image"
New Chrome Apps APIs: webview.request, media gallery write support and downloads[r 73]
New platform features (both in desktop and mobile): support for the WebRTC Device Enumeration API, allowing users to change their microphones and/or camera on the fly without having to restart the WebRTC call; DevTools now supports CSS source maps; Chrome will now match the behavior of IE and not honor the Refresh header or tags when the URL to be refreshed to has a javascript: scheme;[r 73]
Android version:

New gesture: swipe horizontally across the top toolbar to quickly switch tabs
New gesture: drag vertically down from the toolbar to enter into the tab switcher view
New gesture: drag down from the menu to open the menu and select wanted item without having to lift finger
WebGL is enabled by default on high-end devices[r 73]
DeviceMotion (device acceleration and rotation rates) events[r 73]
Media Source Extension is enabled on Android 4.1+[r 73]
Two new experimental features behind a flag: Web Speech API (recognition) and the Vibration API[r 73]
iOS version:

New look and feature enhancements for iOS7
Improvements to Fullscreen behavior especially on iPad (iOS7 only)
New Settings UI
Maps and email links launch the Google Maps and Gmail apps (if installed) automatically. You can change your preference in Settings
Stability / security improvements and bug fixes[r 74]

31.0.1650

2013-11-12 (Linux, macOS and Windows)2013-11-14 (Android)2013-11-20 (iOS)

Blink 537.36

3.21.18

Payment requestAutocomplete() on Chrome for Android, Windows, Chrome OS
PNaCl on desktop versions of Chrome
New Chrome Apps APIs: With URL handlers for apps, Chrome App developers can now specify URLs to be handled by a Chrome App. For example, a document link on a website could open a document editor Chrome App. This gives users more seamless entry points into their favorite Chrome Apps.
Directory access for Apps allows Chrome Apps to access and write to user-approved folders. This feature can be used to share files between a Chrome App and a native app. For example, a Chrome App code editor could modify files managed by a native Git client.
SCTP for WebRTC Data Channel allows P2P data transfers between browsers to be either best effort, reliable, or semi reliable, opening up use cases such as gaming.
Alpha channel support for WebM video enables transparency masking (a.k.a. green screen effects) in WebM videos.
Speech recognition with the JavaScript Web Speech API is now supported on Chrome for Android.
window.devicePixelRatio now takes full-page zoom (but not pinch zoom) into account
Support for { alpha: false } in getContext('2d') lets you create an opaque canvas. This is similar to existing WebGL functionality and can improve the rendering performance of your app.
The Media Source API has been unprefixed and is now supported on Chrome for Android. It allows JavaScript to generate media streams for playback, addressing use cases like adaptive streaming and time shifting live streams.
2D canvas now supports the "ellipse" method.
Support for several Mutation Events has been removed. Consider using MutationObserver instead.[r 75]
iOS version:

Fast form completion with Autofill
Long press on an image to search for related images
Stability / security improvements and bug fixes[r 74]

32.0.1700

2014-01-14 (Linux, macOS and Windows)2014-01-15 (Android)2014-01-27 (iOS)

Blink 537.36

3.22.24

Tab indicators for sound, webcam and casting
A different look for Win8 Metro mode
Automatically blocking malware files
A number of new apps/extension APIs
Various under-the-hood changes for stability and performance
Android version:

Add web page shortcuts right to your home screen more easily from the menu
Reduce data usage in Chrome up to 50%. Visit Settings > Bandwidth management > Reduce data usage to enable.[r 76]
iOS version:

Translate
When you come across a page written in a language that you don’t understand, just look for the translation bar. One tap and the page is quickly translated for you.
Reduce Data Usage
Reduce your data usage by up to 50%. Enable this feature and view your savings: Settings > Bandwidth > Reduce Data Usage.
New Tab Page update to make searching faster and easier
This feature is being rolled out and will be available to all users over time, beginning on iPhone.

33.0.1750

2014-02-18 (iOS)2014-02-20 (Linux, macOS and Windows)2014-02-26 (Android)

Blink 537.36

3.23.17

Custom Elements[r 77]
Ogg Opus in MSE and <video>[r 77]
Page Visibility API[r 77]
VTTCue [r 77]
Web Speech API (synthesis)[r 77]
Font-kerning[r 77]
requestAutocomplete()[r 77]
Speech Synthesis[r 77]
Android version:

Download progress notification for file downloads using the Chrome network stack[r 78]
Updated help and feedback UI[r 78]
Support for <datalist> tag[r 78]
iOS version:

Stability and security updates[r 74]

34.0.1847

2014-04-02 (Android)2014-04-08 (Linux, macOS and Windows)2014-04-29 (iOS)

Blink 537.36

3.24.35

Responsive Images and Unprefixed Web Audio
Import supervised users onto new computers
A different look for Windows 8 Metro mode
A number of new apps/extension APIs
New scroll bar look
Ignores autocomplete="off" on password input fields
Android version:

Battery usage optimizations
iOS version:

Updated tour when you start Chrome for the first time
Support for autocomplete in the omnibox for right to left languages

35.0.1916

2014-05-20 (Android)2014-05-20 (Linux, macOS and Windows)2014-05-28 (iOS)

Blink 537.36

3.25.28

More developer control over touch input
New JavaScript features
Unprefixed Shadow DOM v0
A number of new apps/extension APIs
Opus updated to version v1.1
Android version:

Undo Tab Close
Fullscreen video with Subtitles and HTML5 controls
Support for some multi-window devices
iOS version:

Added right-to-left support to the omnibox for Arabic and Hebrew
See your search term in the omnibox, instead of the long search query URL
Easily refine your search queries and view more results on the search results page
Stability improvements and bug fixes[r 74]
Linux version:

Switched graphics interface backend from GTK+ to Aura

36.0.1985

2014-07-15 (iOS)2014-07-16 (Linux, macOS and Windows)2014-07-16 (Android)

Blink 537.36

3.26.31

Rich Notifications Improvements
An Updated Incognito / Guest NTP design
The addition of a Browser crash recovery bubble
Multiple stability and performance improvements[r 79]
Android version:

Improved text rendering on non-mobile optimized sites
Doodles return to the new tab page[r 80]
iOS version:

Allows mobile sites that have added Cast support to work with your Cast-enabled device
Stability improvements and bug fixes[r 81]
Linux version:

Chrome App Launcher[r 79]

37.0.2062

2014-08-26 (Linux, macOS and Windows)2014-09-03 (Android)2014-09-22 (iOS)[citation needed]

Blink 537.36

3.27.34

DirectWrite support on Windows for improved font rendering
A number of new apps/extension APIs
Multiple stability and performance improvements[r 82]
Removal of the showModalDialog API, breaking several enterprise web apps[r 83]
Android version:

Signing into Chrome signs you into your favorite Google sites
Updated look and feel with elements of Material Design
Multiple performance improvements and bug fixes[r 84]
Windows version:

64-bit Windows support[r 85]

38.0.2125

2014-10-07 (Linux, macOS and Windows)2014-10-07 (iOS)2014-10-08 (Android)

Blink 537.36

3.28.71

A number of new apps/extension APIs
Support for logging into sites using FIDO U2F Security Key (a USB or smartcard security token) as a factor in 2-factor authentication[r 86]
Under-the-hood changes for stability and performance[r 87]
Android version:

Support for Battery Status and Screen orientation APIs
Additional Material Design updates
Bug fixes and performance improvements[r 88]
iOS version:

Better support for iPhone 6 and 6+
Download and open files in Google Drive
Stability improvements and bug fixes
Security fix[r 89]

39.0.2171

2014-11-12 (Android)2014-11-18 (Linux, macOS and Windows)2014-11-24 (iOS)[citation needed]

Blink 537.36

3.29.88

Removes SSL/TLS protocol version fallback to SSLv3
64-bit support for Mac
A number of new apps/extension APIs
Under-the-hood changes for stability and performance[r 90]
Android version:

Number of bug fixes and performance improvements[r 91]
Experimental Reader Mode[r 92] can be enabled via chrome://flags[permanent dead link], is not available for tablets in this version

40.0.2214

2015-01-20 (iOS)2015-01-21 (Linux, macOS and Windows)2015-01-21 (Android)

Blink 537.36

3.30.33

Disabled SSLv3 support by default
The minimum SSL/TLS version can now be set through about:flags
Updated info dialog for Chrome app on Windows and Linux
A new clock behind/ahead error message[r 93]
Android version:

Updated page info and content settings UI
Number of bug fixes and performance improvements[r 94]
iOS version:

New look with Material Design bringing bold graphics, fluid motion, and tactile surfaces
iOS 8 optimizations and support for bigger phones
Support handoff from Chrome to your default browser on macOS
Stability improvements and bug fixes[r 95]

41.0.2272

2015-03-03 (Linux, macOS and Windows)2015-03-11 (Android)2015-03-16 (iOS)

Blink 537.36

4.1.0

A number of new apps/extension APIs
Lots of under the hood changes for stability and performance[r 96]
Aero interface is disabled in Windows Vista
Android version:

The ability to pull to reload at the top of most pages
A number of bug fixes and performance improvements[r 97]

42.0.2311

2015-04-14 (Linux, macOS and Windows)2015-04-15 (Android)2015-04-16 (iOS)

Blink 537.36

4.2.77

Support for NPAPI plugins disabled by default
A number of new apps, extension and Web Platform APIs (including the Push API)
Lots of under the hood changes for stability and performance[r 98]
Add Bookmark is now redesigned.
Android version:

Getting the latest updates from sites with notifications
Adding your favorite sites to your homescreen is now even easier
Bug fixes and speedy performance improvements[r 99]

43.0.2357

2015-05-19 (Linux, macOS and Windows)2015-05-27 (Android)2015-06-01 (iOS)

Blink 537.36

4.3.61

Numerous bug fixes and security fixes[r 100]
Android version:

Faster Checkout – Quickly and securely complete checkout forms with data from Google Wallet
Touch to Search – Learn more about words and phrases by touching them on your screen
Bug fixes and speedy performance improvements[r 101]
No longer supports Android 4.0 (Ice Cream Sandwich)[r 102][r 103]

44.0.2403

2015-07-21 (Linux, macOS and Windows)2015-07-22 (iOS)2015-07-29 (Android)

Blink 537.36

4.4.63

A number of new apps/extension APIs
Change in the loading page circle on Chrome tabs
Lots of under the hood changes for stability and performance[r 104]
Android version:

Fixed a boatload of bugs and performance issues.[r 105]
iOS version:

Swipe to navigate: swipe right or left to navigate backwards and forwards
Support for accessing Physical Web content from the Today view
Stability improvements and bug fixes[r 106]

45.0.2454

2015-09-01 (Linux, macOS and Windows)2015-09-01 (Android)2015-09-02 (iOS)

Blink 537.36

4.5.103

Support for NPAPI plugins permanently disabled
A number of fixes and improvements[r 107]
Android version:

A number of fixes for a whole bunch of performance/stability/other issues.[r 108]

46.0.2490

2015-10-13 (Linux, macOS and Windows)2015-10-14 (Android)2015-10-22 (iOS)

Blink 537.36

4.6.85

Change in taskbar logo design
A number of fixes and improvements.[r 109]
Android version:

Under the hood performance and stability tweaks.[r 110]

47.0.2526

2015-12-01 (iOS)2015-12-01 (Linux, macOS and Windows)2015-12-02 (Android)

Blink 537.36

4.7.80

Change in appearance on closing tabs with red x's
New PDF viewer design
Security fixes[r 111]
Android version:

"More than a barge load of performance and stability fixes".[r 112]
iOS version:

Added support for more keyboard shortcuts. Bluetooth keyboards can open, close or change tabs or conduct a voice search.
Support for 3D touch on iPhone 6s/+. Force touch the Chrome icon to quickly open a new tab, a new incognito* tab, or conduct a voice search.[citation needed]

48.0.2564

2016-01-20 (Linux, macOS and Windows)2016-01-27 (iOS)2016-01-27 (Android)

Blink 537.36

4.8.271

"Tab discarding" was enabled by default in chrome://flags[permanent dead link]
Window change in right-clicking an embedded web link
The key icon in "Save your password" turns black
"Clear browsing history" has been improved
A large number of fixes and improvements[r 113]
Android version:

Bug fixes and speedy performance improvements.
iOS version:

This version uses WKWebView, the latest rendering engine from Apple.
The crash rate was reduced by 70% and JavaScript execution is now faster.
Redesigned icons on the New Tab page: easier access to more of your frequently-visited sites.
Spotlight integration: Drag down or right from the Home screen and search for your Chrome bookmarks.[citation needed]

49.0.2623

2016-03-02 (Linux, macOS and Windows)2016-03-09 (iOS)2016-03-09 (Android)

Blink 537.36

4.9.385

Extension icons now appear near search tab.
Changes in bookmark bar appearances.
Change in Incognito mode window.
Change in scrollbar movement.
Changed Downloads page appearance/design.
A large number of fixes and improvements[r 114]
Removed Windows 8 Mode (Metro mode)
Last version available for Windows XP and Vista, as well as Mac OS X 10.6, 10.7, and 10.8.
Android version:

"More than a barge full of performance and stability fixes."[r 115]
iOS version:

Bookmarks has a new look: Easily find your favorites!
Bug and stability fixes.

50.0.2661

2016-04-13 (Linux, macOS and Windows)2016-04-20 (iOS)2016-04-26 (Android)

Blink 537.36

5.0.71

Auto-fill form letters are now highlighted in bold.
A number of fixes and improvements.[r 116]
No longer supports Windows XP and Vista.
Android version:

Bug fixes and speedy performance improvements.
iOS version:

Bug and stability fixes.

51.0.2704

2016-05-25(Linux, macOS and Windows)2016-06-01 (iOS)2016-06-01 (Android)

Blink 537.36

5.1.281

A number of fixes and improvements.[r 117]
Android version:

Brought tab switching back into Chrome (Android L+)[r 118]
Bug fixes and speedy performance improvements.
iOS version:

Bug and stability fixes.

52.0.2743

2016-07-20 (Linux, macOS and Windows)2016-07-27 (iOS)2016-07-27 (Android)

Blink 537.36

5.2.361

It is impossible to disable DirectWrite.
Bar on the bottom now shows darker text when hovering your mouse over the link.
"A number of fixes and improvements."[r 119]
Android version:

Bug fixes and speedy performance improvements[r 120]
iOS version:

Accelerated Mobile Pages ("AMP") – news and articles from many of your favorite publishers will now load instantly.
Lightning bolt and "AMP" next to articles in the "Top Stories" section of search results indicate faster web page loading.

53.0.2785

2016-08-31 (Linux, macOS and Windows)2016-09-07 (iOS)2016-09-07 (Android)

Blink 537.36

5.3.332

New browser's inside look, including a new bookmark
"A number of fixes and improvements."[r 121]
'Simplify page' option removed from 'Save as PDF'.
Shadow DOM v1[1]
Android version:

Bug fixes and speedy performance improvements[r 122]
Muted autoplay for video[r 123]
iOS version:

Chrome's History has a new look and it's now easier to review, find, and delete your browsing history.
Voice Search has been updated with a fresh look. Voice Search can now answer contextual questions such as "How tall is the Eiffel Tower?" followed by "When was it built?"

54.0.2840

2016-10-12 (Linux, macOS and Windows)2016-10-19 (iOS)2016-10-19 (Android)

Blink 537.36

5.4.500

"Other bookmarks" tab has changed appearance
The message "Right-click to play Adobe Flash Player" now appears while pages with Adobe Flash Player are loading.
"A number of fixes and improvements."[r 124]
Android version:

Bug fixes and speedy performance improvements
View article suggestions for you on the new tab page
Play media in the background for sites that support it
Update saved passwords when you change or reset your password[r 125]
iOS version:

No internet connection? Smile and tap the dinosaur
Fixed bookmark icons not displaying correctly
Fixed phone number detection issues in web pages
Stability improvements and bug fixes

55.0.2883

2016-12-01 (Linux, macOS and Windows)2016-12-05 (iOS)2016-12-06 (Android)

Blink 537.36

5.5.372

The History page has changed and is no longer in "Settings"
Flash Player is now off by default for most sites
"A number of fixes and improvements."[r 126]
It is not possible to disable top level Material Design[r 127]
iOS version:

You can swipe down or right from the iOS Home screen to search. Searching for "voice" or "incognito" enables you to start Chrome in Voice Search mode or in a new Incognito Tab, respectively. The appearance of items in Spotlight Search will only work for devices that support Spotlight Actions.
The folder named "All Bookmarks" has been removed from the Bookmarks view. You can access all your other devices’ Bookmarks by clicking on the other folders.
Android version:

Bug fixes and speedy performance improvements
Easily download music, videos, and even full web pages for viewing offline
View and share your downloads within Chrome
See misspelled words highlighted in text fields
Improvements to contextual search UI[r 128]

56.0.2924

2017-01-25 (Linux, macOS and Windows)2017-02-01 (iOS)2017-02-01 (Android)

Blink 537.36

5.6.326

HTML5 enabled by default
Adobe Flash Player is automatically blocked for most sites that require the plugin
Labeling of unsecured HTTP sites
"A number of fixes and improvements."[r 129]
iOS version:

Scan a QR code or barcode by using 3D Touch on the app logo or searching for "QR" in Spotlight.
We've redesigned the tab switcher layout on iPad to make it easier to access your open sites.
Android version:

Easily download music, videos, and even full web pages for viewing offline
View and share your downloads within Chrome
See misspelled words highlighted in text fields
Improvements to contextual search UI
Bug fixes and significant memory savings[r 130]

57.0.2987

2017-03-09 (Linux, macOS and Windows)2017-03-14 (iOS)2017-03-16 (Android)

Blink 537.36

5.7.492

CSS grid layout
Improved "Add to Home" screen
Media Session API
"A number of fixes and improvements."[r 131]
WebAssembly[r 132]
Background tab policy changes[2]
iOS version:

Chrome can add pages to your Reading List.
Find in Page now works correctly in iOS 10.3.
Android version:

Quickly use emails, addresses, and phone numbers in web pages by tapping on them
Easily access downloaded files and web pages from the new tab page
Long press article suggestions on the new tab page to download them
Bug fixes and performance improvements[r 133]

58.0.3029

2017-04-19 (Linux, macOS and Windows)2017-04-20 (Android)2017-04-25 (iOS)

Blink 537.36

5.8.283

"A number of fixes and improvements."[r 134]
IndexedDB 2.0
Workers and SharedWorkers in data-URLs.
Android version:

Useful actions like “Find in page” available in apps that open web pages using Chrome
More frequently updated article suggestions on the New Tab page
Use recently visited search engines as your default search engine
See Physical Web suggestions, based on your surroundings, in the address bar
Bug fixes and performance improvements[r 135]
iOS version:

Stability improvements and bug fixes.

59.0.3071

2017-06-05 (Linux, macOS and Windows)2017-06-06 (iOS)2017-06-06 (Android)

Blink 537.36

5.9.211

"A number of fixes and improvements."[r 136]
Revamped Settings and "About Google Chrome" page with Material Design
Headless mode in Linux and macOS.[r 137]
iOS version:

Fixed a user-reported issue that resulted in hangs and significant slowdowns when switching tabs.
Fixed a crash involving dialogs presented while switching tabs.
Stability improvements and bug fixes.
Android version:

View and manage in-progress downloads on the Downloads page
View and clear your browsing data more easily on the redesigned History page
Long-press a link to open it in a new Chrome tab (from Chrome Custom Tabs)
Bug fixes and performance improvements[r 138]

60.0.3112

2017-07-25 (Linux, macOS and Windows)2017-07-25 (iOS)2017-07-31 (Android)

Blink 537.36

6.0.286

MacBook Pro Touch Bar support.
"A number of fixes and improvements."[r 139]
iOS version:

"Request Mobile Site" button can switch from a website's desktop version back to its mobile version
Android version:

Load pages faster and use less memory with an updated JavaScript engine
Bug fixes and performance improvements
Clear browsing data more easily[r 140]

61.0.3163

2017-09-05 (Linux, macOS and Windows)2017-09-05 (iOS)2017-09-05 (Android)

Blink 537.36

6.1.534

Native support for JavaScript modules
"A number of fixes and improvements."[r 141]
iOS version:

Added a new button for scanning QR codes above the virtual keyboard
Android version:

Addition of Web Share API
Bug fixes and performance improvements
Translate pages with a more compact and intuitive toolbar
Pick images to post online with an improved image picker[r 142]

62.0.3202

2017-10-17 (Linux, macOS and Windows)2017-10-18 (iOS)2017-10-19 (Android)

Blink 537.36

6.2.414

The "Save Your Password" icon gets a new appearance
"A number of fixes and improvements."[r 143]
Support for OpenType variable fonts
Network Information API updated to report users actual Internet speed, not just connection type, to websites
HTTP sites that request user data will now be flagged as "non-secure" (red) in the Chrome Omnibox[r 144]
iOS version:

Two new Today widgets are added by tapping the Edit button at the bottom of the iOS Search screen
Ability to drag a URL from another app and drop it into Chrome's omnibox or the tab strip, or from Chrome's content area to another app on iOS 11 iPads
The Payment Request API has been introduced
Android version:

Download files faster with accelerated downloads
View and copy passwords saved with Chrome if device lock is enabled
Quickly see your data savings in the Chrome menu when Data Saver is on[r 145]

63.0.3239

2017-12-05 (iOS)2017-12-05 (Android)2017-12-06 (Linux, macOS and Windows)

Blink 537.36

6.3.292

Various fixes from internal audits, fuzzing and other initiatives
"A number of fixes and improvements."[r 146]
Browser allows you to import JavaScript modules dynamically
With async generator functions and the async iteration protocol, consumption or implementation of streaming data sources becomes streamlined
You can override the browser's default overflow scroll behavior with the CSS overscroll-behavior property[r 147]
iOS version:

Swipe up on the New Tab Page to explore suggested content from the web
The ability to reorder bookmarks is back!
Android version:

Chrome for Android will make permission requests modal dialogs
"Stability and performance improvements."[r 148]

64.0.3282

2018-01-23 (Android)2018-01-24 (iOS)2018-01-24 (Linux, macOS and Windows)

Blink 537.36

6.4.388

"A number of fixes and improvements."[r 149]
Support for ResizeObservers, will notify you when an element’s content rectangle has changed its size.
Modules can now access to host specific metadata with import.meta.
The pop-up blocker gets stronger.
window.alert() no longer changes tab focus.
Chrome now supports named captures in regular expressions.
The default preload value for <audio> and <video> elements is now metadata.
You can now use Request.prototype.cache to view the cache mode of a Request and determine whether a request is a reload request.
Using the Focus Management API, you can now focus an element without scrolling to it with the preventScroll attribute.[r 150]
Android version:

Prevents sites with abusive ad experiences from opening new windows or tabs without your permission.
"Stability and performance improvements."[r 151]
iOS version:

You can now disable Article Suggestions without also disabling omnibox suggestions by going to Chrome Settings
If you previously turned off "Search and Site Suggestions" to disable Article Suggestions and would like to turn back on your Search Suggestions in the omnibox, you can do that from Chrome Settings > Privacy
Support for iPhone X
Now requires iOS 10 or later

65.0.3325

2018-03-06 (Linux, macOS and Windows)2018-03-06 (iOS)2018-03-06 (Android)

Blink 537.36

6.5.254

"A number of fixes and improvements."[r 152]
New extension UI
The CSS Paint API allows you to programmatically generate an image
The Server Timing API allows web servers to provide performance timing information via HTTP headers
The new CSS display: contents property can make boxes disappear
Fixed a bug that affected some timestamps
The syntax for specifying HSL and HSLA, and RGB and RGBA coordinates for the color property now match the CSS Color 4 spec
There's a new feature policy that allows you to control synchronous XHRs through an HTTP header or the iframe allow attribute[r 153]
Last version available for OS X 10.9.
Android version:

Set language preferences for web content in Settings > Languages
Turn on the prompt for simplified view for all supported articles in Settings > Accessibility settings
Share and delete downloads more easily on the Downloads page[r 154]
Disable screen capture on incognite mode [3]
iOS version:

Fixed a bug that affected some streaming audio players
Stability and performance improvements

66.0.3359

2018-04-17 (Linux, macOS and Windows)2018-04-17 (iOS)2018-04-17 (Android)

Blink 537.36

6.6.346

"A number of fixes and improvements."[r 155]
CSS manipulation becomes easier with the new CSS Typed Model Object
Access to the clipboard is now asynchronous
There's a new rendering context for canvas elements
TextArea and Select now support the autocomplete attribute
Setting autocapitalize on a form element will apply to any child form fields, improving compatibility with Safari's implementation of autocapitalize
trimStart() and trimEnd() are now available as the standards-based way of trimming whitespace from strings[r 156]
Android version:

Find your saved passwords more easily – just tap the new Search icon in Settings > Passwords[r 157]
iOS version:

Export passwords saved in Chrome and use them in another app
Stability and performance improvements

67.0.3396

2018-05-29 (Linux, macOS and Windows)2018-05-29 (iOS)2018-05-31 (Android)

Blink 537.36

6.7.288

"A number of fixes and improvements."[r 158]
Progressive Web Apps are coming to the desktop
The generic sensor API makes it way easier to get access to device sensors like the accelerometer, gyroscope and more
BigInt's make dealing with big integers way easier.
Credential Management API provides a framework for creating, retrieving and storing credentials
The Web Authentication API adds a third credential type, PublicKeyCredential, which allows browsers to authenticate a user with a private/public key pair generated by an authenticator[r 159]
Android version:

"Stability and performance improvements."[r 160]
iOS version:

Improved handling of boarding passes, movie tickets, etc. in Wallet
Updated app selection UI when you tap on an email link
Improved support for external keyboards
Improved issue reporting: now you can draw on screenshots you are sending with feedback reports to obscure private data
A fix has been provided for autofill issue (June 13)

68.0.3440

2018-07-24 (iOS)2018-07-24 (Linux, macOS and Windows)2018-07-24 (Android)

Blink 537.36

6.8.275

"A number of fixes and improvements."
HTTP sites marked as "not secure".[r 161]
The Page Lifecycle API tells you when your tab has been suspended or restored.
The Payment Handler API makes it possible for web-based payment apps to support the Payment Request experience.
Content embedded in an iframe requires a user gesture to navigate the top-level browsing context to a different origin.
Since Chrome 1, the CSS cursor values for grab and grabbing have been prefixed; standard, un-prefixed values now supported.[r 162]
Android version:

Fix for an Autofill issue.[r 163]
The Add to Home Screen behavior on Android is changing to give you more control.
iOS version:

Improved downloading from websites. Downloading now works while the app is in the background. You can also continue browsing in the same tab while your file downloads.
Improvements to Forms Autofill.
Improved handling of links to the App Store.

69.0.3497

2018-08-02 (Linux, macOS and Windows)

Blink 537.36

6.9

Current Beta channel

70.0

2018-08-03 (Linux, macOS and Windows)

Blink 537.36

7.0

Current Dev channel

70.0

2018-07-21 (Windows, macOS and Android)

Blink 537.36

7.0

Current Canary channel

Major version

Release date

Layout engine[r 1]

V8 engine[r 2]

Significant changes

text: Notes[edit]

text:
Release date is the date of first release.  All channels have subsequent updates which are not shown. For release update history see Google Chrome Releases.
The first stable release in Windows, macOS and Linux was Google Chrome 5.0.375. The first stable release on Android was Chrome 18.0.1025123 (Chrome for Android).[r 164][r 165][r 166]
Old development and beta builds are not shown after they become stable releases.
As of Chrome 26, Linux installations of the browser may be updated only on systems that support GCC v4.6 and GTK v2.24 or later. Thus systems such as Ubuntu Lucid 10.04 LTS, Debian 6's 2.20, and RHEL 6's 2.18 are now among those marked as deprecated.[r 167]
As of Chrome 59, Linux Chrome defaults to GTK+3. Older versions of Linux, e.g. RHEL 6 or CentOS 6, with only GTK+2 support, are not able to run this version of Chrome. Red Hat's GTK+2 build of Firefox ESR is probably the last remaining regularly updated browser on RHEL 6/CentOS 6.[4]
Versions 6–32 had Google Chrome Frame counterparts, until its development was discontinued.[r 168][not in citation given]
As of version 50, macOS 10.6, 10.7, 10.8, Windows XP and Vista are no longer supported.
Standalone builds can be found on Google's Chromium Browser Continuous build server.


document_title: Ball joint

question_text: where are ball joints located on a truck

root

text: Ball joint

text: Theory[edit]

text: A ball joint is used for allowing free rotation in two planes at the same time while preventing translation in any direction,[1] including rotating in those planes. Combining two such joints with control arms enables motion in all three planes, allowing the front end of an automobile to be steered and a spring and shock (damper) suspension to make the ride comfortable.

tag: p

text: A simple kingpin suspension requires that the upper and lower control arms (wishbones) have pivot axes that are parallel, and in strict geometric relationship to the kingpin, or the top and bottom trunnions, which connect the kingpin to the control arms, would be severely stressed and the bearings would suffer severe wear. In practice, many vehicles had elastomeric bearings in the horizontal pivots of the trunnions, which allowed some small amount of flexibility, however this was insufficient to allow much adjustment of caster to be made, and also introduced compliance where the suspension designer may not have desired it in his quest for optimum handling. camber angle could generally be adjusted by moving both inner pivots of either the upper or lower control arm inwards or outwards by an exactly equal amount. But compliance of the control arm inner pivots, typically due to the use of elastomeric bearings, would again cause the trunnions to be stressed. The suspension designer's freedom was severely limited, it was necessary to have some compliance where it might not be wanted, and very little where more would have been useful in absorbing the fore and aft impact loading from bumps.

text: The introduction of ball joints top and bottom allowed 3-axis articulation and so removed all the constraints on the control arm axes being exactly parallel, so caster could be freely adjusted, typically by asymmetric adjustment of the position of the control arm inner pivots, while camber was adjusted by the symmetric adjustment of these same pivots.

text: The arrangements for adjusting the toe angle are not changed by introducing ball joints in the suspension, although it should be noted that the steering linkage itself must use 4 or more pivots, also usually ball joints, and in almost every vehicle ever made, some of these have been adjustable by having a threaded end and locknut, to enable the toe to be set precisely.

text: This ability to fine-tune ball-jointed suspension allows manufacturers to make the automobile more stable and easier to steer, compared to the older kingpin style suspension. It may also be quieter and more comfortable, because lateral and fore and aft compliance in the suspension can be introduced in controlled amounts at the control arm inner pivots without compromising the integrity of the steering axis pivots, which are now ball joints instead of a king pin and trunnions. The smoother ride may also increase tire tread life, since the ball-joint suspension allows better control of suspension geometry and so can provide better tire-to-road contact.

text: Purpose[edit]

text: On modern vehicles, ball joints are the pivot between the wheels and the suspension of an automobile. They are today almost universally used in the front suspension, having replaced the kingpin/linkpin or kingpin/trunnion arrangement, but can also be found in the rear suspension of a few higher-performance autos.[4] Ball joints play a critical role in the safe operation of an automobile's steering and suspension.

text: Many currently manufactured automobiles worldwide use MacPherson strut suspension, which utilises one ball joint per side, between the lower end of the strut and the control arm, with the necessary small amount of articulation at the top of the strut being usually provided by an elastomeric bearing, within which is a ball bearing to allow free rotation about the steering axis. So, there are commonly only two ball joints in the suspension, however there will be at least four (track rod ends and rack ends) in the steering linkage.

text: In non-MacPherson strut automobile suspension, the two ball joints are called the "upper ball joint" and "lower ball joint". Lower ball joints are sometimes larger and may wear out faster, because the fore and aft loads, primarily due to braking, are higher at the bottom ball joint. (Torque reaction and drag add at the bottom joint, and partly cancel at the top joint.) Also, lateral cornering loads are higher at the bottom joint. Depending on the suspension design, the vertical load from the suspension spring may be handled entirely by the top ball joint, or entirely by the bottom ball joint. The damper load, (which is low in normal conditions, zero when stationary, but in peak bump or rebound rate may be almost as large as the spring load) is usually, but not always, taken on the same ball joint as the spring load. The anti-roll bar loading is often, but not always, taken on the bottom ball joint. It may be taken by the top ball joint, or directly from the steering knuckle by ball-jointed drop links.

text: If one of the ball joints does not carry spring load, it may be fitted with an internal anti-rattle spring to keep the ball preferentially in contact with one seat. This was the case in the BMC Mini of 1959 and its many derivatives, where the lower control arm carried no vertical loading, so the joint needed and anti-rattle spring, while the top joint, comprising identical parts, was always in compression due to spring (rubber cone) and damper loads, and so was not fitted with a spring.

text: Other vehicles of the 1960s era, including some Vauxhalls, had lower ball joints with considerable end float, because the joint was always in tension as the spring and damper loads were applied via the lower control arm and were always non-zero.

text: Another example is the Ford Focus, which uses MacPherson struts, and the anti-roll bar is connected directly to the strut, so the lower ball joint is only carrying fore and aft traction/braking and lateral cornering loads.

text: Front-wheel drive[edit]

text: Unlike a kingpin, which requires an assembly in the center of the wheel in order to pivot, joints connect to the upper and lower end of the spindle (steering knuckle), to the control arms. This leaves the center section open to allow the use of front-wheel drive. Older kingpin designs can only be used in a rear-wheel-drive configuration.

text: Lubrication[edit]

text: Sealed ball joints do not require lubrication as they are "lubed for life". Formerly most ball joints had grease fitting (sometimes called a grease zerk) and were designed for periodic addition of a lubricant, however almost all modern cars use sealed ball joints to minimise maintenance requirements. The lubricant was usually a very high-viscosity lubricant. It is commonly believed that standard ball joints will outlive sealed ones because eventually the seal will break, causing the joint to dry out and rust.[4] Additionally, the act of adding new lubricant pushes out old and dry lubricant, extending the life of the joint. This was supposed to be done at intervals of 1000 to 2000 miles on many vehicles, which is incompatible with the service interval on modern cars, often 12000 miles or more, and in any case was rarely attended to by owners, resulting in severe wear and possible ball joint failure, which can result in serious accidents. For this reason, almost all ball joints on modern European or Far Eastern cars are the sealed for life type. New technology especially applied to the internal bearing design has allowed ball joints to meet these longer service intervals. The special design's incorporate sintered metal bearings which replace OEM sealed polymer/plastic version and improved dust boot seal's that work much better at retaining the grease.

text: Spherical rolling joint[edit]

text: A spherical rolling joint is a high-precision ball joint consisting of a spherical outer and inner race separated by ball bearings. The ball bearings are housed in a spherical retainer and roll along both the inner and outer surfaces. This design allows the joint to have very low friction while maintaining a large range of motion and backlash as low as 1 µm. SRJs are often used in parallel robotics applications like a Stewart platform, where high rigidity and low backlash are essential.[5][6]

text: Most SRJs are designed with an offset housing, allowing for higher compressive loads in a smaller space. Alternatively, the joint can be assembled backwards for higher tensile load capability but less range of motion.

text: An alternative to the SRJ is the universal joint, which consists of two revolute joints.[7] By using spherical rolling joints instead of universal, designers can reduce the number of joints to achieve the same result. Using a spherical joint as opposed to a universal joint also eliminates the problematic possibility of a kinematic singularity.[8] Plain spherical bearings can be used in place of SRJs at the cost of increased friction, but offer an opportunity to preload the joint further.

text: Failure[edit]

text: While there is no exact lifespan that can be put on sealed ball joints, they can fail as early as 80,000 miles (130,000 km) in modern vehicles, and much sooner in older vehicles.[citation needed] Signs of a failing ball joint may start with a sudden burst sound as a result of ball joint dismantling. Then it keeps on with clicking, popping or snapping sound when the wheel is turned and eventually turn into a squeaking sound at the end of a stop, when the gas pedal is used and/or also when hitting bumps. Another symptom could be 'thud' noises coming from front suspension when going over bumps. Dry ball joints have dramatically increased friction and can cause the steering to stick or be more difficult.

text: If a ball joint fails, the results can be dangerous as the wheel's angle becomes unconstrained, causing loss of control. Because the tire will be at an unintended angle, the vehicle will come to an abrupt halt, damaging the tires. Also, during failure, debris can damage other parts of the vehicle.[4]

text: Other uses[edit]

text: While in automotive parlance the term "ball joint" usually refers to the primary ball joint connections at the ends of the control arms, this type of joint is used in other parts as well, including tie rod ends. In these other applications, they are typically called tie rod ends or, when they are an inner tie rod end on a rack-and-pinion steering system, they are called inner socket assemblies. These joints are also used in a number of other non-automotive applications, from the joints of dolls to other mechanical linkages for a variety of devices, or any place where a degree of rotation in movement is desired.


document_title: You Can't Judge a Book by the Cover

question_text: who wrote you can't judge a book by its cover

question_tokens: who wrote you ca n 't judge a book by its cover

text: You Can't Judge a Book by the Cover

text:
"You Can't Judge a Book by the Cover"

Single by Bo Diddley

from the album Bo Diddley

B-side
"I Can Tell"

Released
July 1962 (1962-07)

Format
7-inch 45 rpm record

Recorded
Chicago, June 27, 1962

Genre
Rock and roll, rhythm and blues

Length
2:43[1]

Label
Checker (no. 1019)

Songwriter(s)
Willie Dixon

Producer(s)
Ralph Bass

tag: table

text: "You Can't Judge a Book by the Cover" is a 1962 song by rock and roll pioneer Bo Diddley. Written by Willie Dixon, the song was one of Diddley's last record chart hits.[2] Unlike many of his well-known songs, "You Can't Judge a Book by the Cover" does not rely on the Bo Diddley beat.[3] A variety of rock and other performers have recorded renditions of the song.

text: Original song[edit]

text: "You Can't Judge a Book by the Cover" is based on a sixteen-bar blues structure that "boasts a beat that's utterly compulsive and primordial, but closer to a way-speeded up walking rhythm than to the standard Diddley pattern".[3] Willie Dixon's lyrics use "a series of metaphors of all sorts of things you can't judge by their appearances before landing on the title phrase".[3]

text:
You can't judge an apple by looking at a tree
You can't judge honey by looking at the bee
You can't judge a daughter by looking at the mother
You can't judge a book by looking at the cover

text: In his autobiography, Dixon explained that the lyrics were "his [Bo Diddley's] bag 100% ... and when I told him about it, he like it immediately".[4] Diddley's original recording breaks the fourth wall by encouraging the listener to turn his or her radio up after the first verse. In 1962, the song reached number 21 on the Billboard magazine R&B chart and number 48 on the Billboard Hot 100.[2]

text: Later renditions[edit]

text: "You Can't Judge a Book by the Cover" has been recorded by a variety of artists,[3] often with variations in the title, such as "You Can't Judge a Book by Its Cover" or "You Can't Judge a Book by Looking at the Cover". An early lineup of the Rolling Stones made a demo recording of the song in October 1962. In 1963, the Yardbirds with Eric Clapton recorded a live version of the song at the Crawdaddy Club in London during the sessions that produced the Sonny Boy Williamson and The Yardbirds album. In 1964, the song was performed on Germany's Beat-Club television program by the Syndicats, featuring guitarist Steve Howe. In 1966, folk singer Tom Rush recorded it for the album Take a Little Walk with Me. Also in 1966, garage band Shadows of Knight released their first album "Gloria" which included their own version. The Monkees recorded it their Live 1967 album with lead vocals by Mike Nesmith. On January 26, 1972, Jerry Garcia and Howard Wales performed an up-tempo version of the song in closing a concert set at Symphony Hall, Boston.[5]

text: Later versions include those by Cactus (1970 Cactus), Long John Baldry on his 1972 album Everything Stops for Tea, the Beat Farmers (2003 Live at the Spring Valley Inn, 1983), and the Fabulous Thunderbirds (1992 Hot Stuff). Hank Williams, Jr. recorded it as a duet with Huey Lewis on his 1986 album, Montana Cafe, and Roy Buchanan (with Delbert McClinton) (2011 Alligator Records 40th Anniversary Collection). The Strypes included a version on their 2012 debut EP Young Gifted & Blue. Kenny Wayne Shepherd Band's seventh studio album Goin' Home, released in May 2014, includes a version of the song with vocals by longtime vocalist (and rhythm guitarist) Noah Hunt and guest vocalist Pastor Brady Blade Sr.

text: On January 22, 2018, a cover was released featuring SZA and an eclectic group of up-and-coming artists from a variety of genres for MasterCard's Start Something Priceless Movement.[6] The other artists include The Tracks, Radkey, Victoria Canal, William Prince, Noe Socha, and Ruby Ibarra. They were chosen for having triumphed over adversity to succeed. "Some have overcome a disability, such as Noe Socha who is blind, or Canal who is missing a hand, while others have overcome prejudice, such as Radkey who are a black rock group."[7]


document_title: Karyotype

question_text: how many chromosomes are in a human karyotype

text: Karyotype

text: History of karyotype studies[edit]

text: Chromosomes were first observed in plant cells by Carl Wilhelm von Nägeli in 1842. Their behavior in animal (salamander) cells was described by Walther Flemming, the discoverer of mitosis, in 1882. The name was coined by another German anatomist, Heinrich von Waldeyer in 1888. It is New Latin from Ancient Greek κάρυον karyon, "kernel", "seed", or "nucleus", and τύπος typos, "general form").

text: The next stage took place after the development of genetics in the early 20th century, when it was appreciated that chromosomes (that can be observed by karyotype) were the carrier of genes. Lev Delaunay (ru) seems to have been the first person to define the karyotype as the phenotypic appearance of the somatic chromosomes, in contrast to their genic contents (1922).[6][7] The subsequent history of the concept can be followed in the works of C. D. Darlington[8] and Michael JD White.[2][9]

text: Investigation into the human karyotype took many years to settle the most basic question: how many chromosomes does a normal diploid human cell contain?[10] In 1912, Hans von Winiwarter reported 47 chromosomes in spermatogonia and 48 in oogonia, concluding an XX/XO sex determination mechanism.[11] Painter in 1922 was not certain whether the diploid of humans was 46 or 48, at first favoring 46,[12] but revised his opinion from 46 to 48, and he correctly insisted on humans having an XX/XY system.[13] Considering the techniques of the time, these results were remarkable.

text: In textbooks, the number of human chromosomes remained at 48 for over thirty years. New techniques were needed to correct this error. Joe Hin Tjio working in Albert Levan's lab[14] was responsible for finding the approach:

text:
Using cells in tissue culture
Pretreating cells in a hypotonic solution, which swells them and spreads the chromosomes
Arresting mitosis in metaphase by a solution of colchicine
Squashing the preparation on the slide forcing the chromosomes into a single plane
Cutting up a photomicrograph and arranging the result into an indisputable karyogram.

tag: ol

text: The work took place in 1955, and was published in 1956. The karyotype of humans includes only 46 chromosomes.[15][16] Rather interestingly, the great apes have 48 chromosomes. Human chromosome 2 is now known to be a result of an end-to-end fusion of two ancestral ape chromosomes.[17][18]

text: Observations on karyotypes[edit]

text: Staining[edit]

text: The study of karyotypes is made possible by staining. Usually, a suitable dye, such as Giemsa,[19] is applied after cells have been arrested during cell division by a solution of colchicine usually in metaphase or prometaphase when most condensed. In order for the Giemsa stain to adhere correctly, all chromosomal proteins must be digested and removed. For humans, white blood cells are used most frequently because they are easily induced to divide and grow in tissue culture.[20] Sometimes observations may be made on non-dividing (interphase) cells. The sex of an unborn fetus can be determined by observation of interphase cells (see amniotic centesis and Barr body).

text: Observations[edit]

text: Six different characteristics of karyotypes are usually observed and compared:[21]

text:
Differences in absolute sizes of chromosomes. Chromosomes can vary in absolute size by as much as twenty-fold between genera of the same family. For example, the legumes Lotus tenuis and Vicia faba each have six pairs of chromosomes, yet V. faba chromosomes are many times larger. These differences probably reflect different amounts of DNA duplication.
Differences in the position of centromeres. These differences probably came about through translocations.
Differences in relative size of chromosomes. These differences probably arose from segmental interchange of unequal lengths.
Differences in basic number of chromosomes. These differences could have resulted from successive unequal translocations which removed all the essential genetic material from a chromosome, permitting its loss without penalty to the organism (the dislocation hypothesis) or through fusion. Humans have one pair fewer chromosomes than the great apes. Human chromosome 2 appears to have resulted from the fusion of two ancestral chromosomes, and many of the genes of those two original chromosomes have been translocated to other chromosomes.
Differences in number and position of satellites. Satellites are small bodies attached to a chromosome by a thin thread.
Differences in degree and distribution of heterochromatic regions. Heterochromatin stains darker than euchromatin. Heterochromatin is packed tighter. Heterochromatin consists mainly of genetically inactive and repetitive DNA sequences as well as containing a larger amount of Adenine-Thymine pairs. Euchromatin is usually under active transcription and stains much lighter as it has less affinity for the giemsa stain.[22] Euchromatin regions contain larger amounts of Guanine-Cytosine pairs. The staining technique using giemsa staining is called G banding and therefore produces the typical "G-Bands".[22]

text: A full account of a karyotype may therefore include the number, type, shape and banding of the chromosomes, as well as other cytogenetic information.

text: Variation is often found:

text:
between the sexes,
between the germ-line and soma (between gametes and the rest of the body),
between members of a population (chromosome polymorphism),
in geographic specialization, and
in mosaics or otherwise abnormal individuals.[9]

text: Human karyotype[edit]

text: The normal human karyotypes contain 22 pairs of autosomal chromosomes and one pair of sex chromosomes (allosomes). Normal karyotypes for females contain two X chromosomes and are denoted 46,XX; males have both an X and a Y chromosome denoted 46,XY. Any variation from the standard karyotype may lead to developmental abnormalities.

text: Diversity and evolution of karyotypes[edit]

text: Although the replication and transcription of DNA is highly standardized in eukaryotes, the same cannot be said for their karyotypes, which are highly variable. There is variation between species in chromosome number, and in detailed organization, despite their construction from the same macromolecules. This variation provides the basis for a range of studies in evolutionary cytology.

text: In some cases there is even significant variation within species. In a review, Godfrey and Masters conclude:

text: In our view, it is unlikely that one process or the other can independently account for the wide range of karyotype structures that are observed ... But, used in conjunction with other phylogenetic data, karyotypic fissioning may help to explain dramatic differences in diploid numbers between closely related species, which were previously inexplicable.[23]

text: Although much is known about karyotypes at the descriptive level, and it is clear that changes in karyotype organization has had effects on the evolutionary course of many species, it is quite unclear what the general significance might be.

text: We have a very poor understanding of the causes of karyotype evolution, despite many careful investigations ... the general significance of karyotype evolution is obscure.

text: Changes during development[edit]

text: Instead of the usual gene repression, some organisms go in for large-scale elimination of heterochromatin, or other kinds of visible adjustment to the karyotype.

text:
Chromosome elimination. In some species, as in many sciarid flies, entire chromosomes are eliminated during development.[25]
Chromatin diminution (founding father: Theodor Boveri). In this process, found in some copepods and roundworms such as Ascaris suum, portions of the chromosomes are cast away in particular cells. This process is a carefully organised genome rearrangement where new telomeres are constructed and certain heterochromatin regions are lost.[26][27] In A. suum, all the somatic cell precursors undergo chromatin diminution.[28]
X-inactivation. The inactivation of one X chromosome takes place during the early development of mammals (see Barr body and dosage compensation). In placental mammals, the inactivation is random as between the two Xs; thus the mammalian female is a mosaic in respect of her X chromosomes. In marsupials it is always the paternal X which is inactivated. In human females some 15% of somatic cells escape inactivation,[29] and the number of genes affected on the inactivated X chromosome varies between cells: in fibroblast cells up about 25% of genes on the Barr body escape inactivation.[30]

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text: Number of chromosomes in a set[edit]

text: A spectacular example of variability between closely related species is the muntjac, which was investigated by Kurt Benirschke and his colleague Doris Wurster. The diploid number of the Chinese muntjac, Muntiacus reevesi, was found to be 46, all telocentric. When they looked at the karyotype of the closely related Indian muntjac, Muntiacus muntjak, they were astonished to find it had female = 6, male = 7 chromosomes.[31]

text: They simply could not believe what they saw ... They kept quiet for two or three years because they thought something was wrong with their tissue culture ... But when they obtained a couple more specimens they confirmed [their findings].

text: The number of chromosomes in the karyotype between (relatively) unrelated species is hugely variable. The low record is held by the nematode Parascaris univalens, where the haploid n = 1; and an ant: Myrmecia pilosula.[32] The high record would be somewhere amongst the ferns, with the adder's tongue fern Ophioglossum ahead with an average of 1262 chromosomes.[33] Top score for animals might be the shortnose sturgeon Acipenser brevirostrum at 372 chromosomes.[34] The existence of supernumerary or B chromosomes means that chromosome number can vary even within one interbreeding population; and aneuploids are another example, though in this case they would not be regarded as normal members of the population.

text: Fundamental number[edit]

text: The fundamental number, FN, of a karyotype is the number of visible major chromosomal arms per set of chromosomes.[35][36] Thus, FN ≤ 2 x 2n, the difference depending on the number of chromosomes considered single-armed (acrocentric or telocentric) present. Humans have FN = 82,[37] due to the presence of five acrocentric chromosome pairs: 13, 14, 15, 21, and 22 (the human Y chromosome is also acrocentric). The fundamental autosomal number or autosomal fundamental number, FNa[38] or AN,[39] of a karyotype is the number of visible major chromosomal arms per set of autosomes (non-sex-linked chromosomes).

text: Ploidy[edit]

text: Ploidy is the number of complete sets of chromosomes in a cell.

text:
Polyploidy, where there are more than two sets of homologous chromosomes in the cells, occurs mainly in plants. It has been of major significance in plant evolution according to Stebbins.[40][41][42][43] The proportion of flowering plants which are polyploid was estimated by Stebbins to be 30–35%, but in grasses the average is much higher, about 70%.[44] Polyploidy in lower plants (ferns, horsetails and psilotales) is also common, and some species of ferns have reached levels of polyploidy far in excess of the highest levels known in flowering plants.
Polyploidy in animals is much less common, but it has been significant in some groups.[45]
Polyploid series in related species which consist entirely of multiples of a single basic number are known as euploid.

Haplo-diploidy, where one sex is diploid, and the other haploid. It is a common arrangement in the Hymenoptera, and in some other groups.
Endopolyploidy occurs when in adult differentiated tissues the cells have ceased to divide by mitosis, but the nuclei contain more than the original somatic number of chromosomes.[46] In the endocycle (endomitosis or endoreduplication) chromosomes in a 'resting' nucleus undergo reduplication, the daughter chromosomes separating from each other inside an intact nuclear membrane.[47]
In many instances, endopolyploid nuclei contain tens of thousands of chromosomes (which cannot be exactly counted). The cells do not always contain exact multiples (powers of two), which is why the simple definition 'an increase in the number of chromosome sets caused by replication without cell division' is not quite accurate.
This process (especially studied in insects and some higher plants such as maize) may be a developmental strategy for increasing the productivity of tissues which are highly active in biosynthesis.[48]
The phenomenon occurs sporadically throughout the eukaryote kingdom from protozoa to humans; it is diverse and complex, and serves differentiation and morphogenesis in many ways.[49]
See palaeopolyploidy for the investigation of ancient karyotype duplications.

text: Aneuploidy[edit]

text: Aneuploidy is the condition in which the chromosome number in the cells is not the typical number for the species. This would give rise to a chromosome abnormality such as an extra chromosome or one or more chromosomes lost. Abnormalities in chromosome number usually cause a defect in development. Down syndrome and Turner syndrome are examples of this.

text: Aneuploidy may also occur within a group of closely related species. Classic examples in plants are the genus Crepis, where the gametic (= haploid) numbers form the series x = 3, 4, 5, 6, and 7; and Crocus, where every number from x = 3 to x = 15 is represented by at least one species. Evidence of various kinds shows that trends of evolution have gone in different directions in different groups.[50] Closer to home, the great apes have 24x2 chromosomes whereas humans have 23x2. Human chromosome 2 was formed by a merger of ancestral chromosomes, reducing the number.[51]

text: Chromosomal polymorphism[edit]

text: Some species are polymorphic for different chromosome structural forms.[52] The structural variation may be associated with different numbers of chromosomes in different individuals, which occurs in the ladybird beetle Chilocorus stigma, some mantids of the genus Ameles,[citation needed] the European shrew Sorex araneus.[53] There is some evidence from the case of the mollusc Thais lapillus (the dog whelk) on the Brittany coast, that the two chromosome morphs are adapted to different habitats.[54]

text: Species trees[edit]

text: The detailed study of chromosome banding in insects with polytene chromosomes can reveal relationships between closely related species: the classic example is the study of chromosome banding in Hawaiian drosophilids by Hampton L. Carson.

text: In about 6,500 sq mi (17,000 km2), the Hawaiian Islands have the most diverse collection of drosophilid flies in the world, living from rainforests to subalpine meadows. These roughly 800 Hawaiian drosophilid species are usually assigned to two genera, Drosophila and Scaptomyza, in the family Drosophilidae.

text: The polytene banding of the 'picture wing' group, the best-studied group of Hawaiian drosophilids, enabled Carson to work out the evolutionary tree long before genome analysis was practicable. In a sense, gene arrangements are visible in the banding patterns of each chromosome. Chromosome rearrangements, especially inversions, make it possible to see which species are closely related.

text: The results are clear. The inversions, when plotted in tree form (and independent of all other information), show a clear "flow" of species from older to newer islands. There are also cases of colonization back to older islands, and skipping of islands, but these are much less frequent. Using K-Ar dating, the present islands date from 0.4 million years ago (mya) (Mauna Kea) to 10mya (Necker). The oldest member of the Hawaiian archipelago still above the sea is Kure Atoll, which can be dated to 30 mya. The archipelago itself (produced by the Pacific plate moving over a hot spot) has existed for far longer, at least into the Cretaceous. Previous islands now beneath the sea (guyots) form the Emperor Seamount Chain.[55]

text: All of the native Drosophila and Scaptomyza species in Hawaiʻi have apparently descended from a single ancestral species that colonized the islands, probably 20 million years ago. The subsequent adaptive radiation was spurred by a lack of competition and a wide variety of niches. Although it would be possible for a single gravid female to colonise an island, it is more likely to have been a group from the same species.[56][57][58][59]

text: There are other animals and plants on the Hawaiian archipelago which have undergone similar, if less spectacular, adaptive radiations.[60][61]

text: Chromosome banding[edit]

text: Chromosomes display a banded pattern when treated with some stains. Bands are alternating light and dark stripes that appear along the lengths of chromosomes. Unique banding patterns are used to identify chromosomes and to diagnose chromosomal aberrations, including chromosome breakage, loss, duplication, translocation or inverted segments. A range of different chromosome treatments produce a range of banding patterns: G-bands, R-bands, C-bands, Q-bands, T-bands and NOR-bands.

text: Depiction of karyotypes[edit]

text: Types of banding[edit]

text: Cytogenetics employs several techniques to visualize different aspects of chromosomes:[20]

text:
G-banding is obtained with Giemsa stain following digestion of chromosomes with trypsin. It yields a series of lightly and darkly stained bands — the dark regions tend to be heterochromatic, late-replicating and AT rich. The light regions tend to be euchromatic, early-replicating and GC rich. This method will normally produce 300–400 bands in a normal, human genome.
R-banding is the reverse of G-banding (the R stands for "reverse"). The dark regions are euchromatic (guanine-cytosine rich regions) and the bright regions are heterochromatic (thymine-adenine rich regions).
C-banding: Giemsa binds to constitutive heterochromatin, so it stains centromeres.The name is derived from centromeric or constitutive heterochromatin. The preparations undergo alkaline denaturation prior to staining leading to an almost complete depurination of the DNA. After washing the probe the remaining DNA is renatured again and stained with Giemsa solution consisting of methylene azure, methylene violet, methylene blue, and eosin. Heterochromatin binds a lot of the dye, while the rest of the chromosomes absorb only little of it. The C-bonding proved to be especially well-suited for the characterization of plant chromosomes.
Q-banding is a fluorescent pattern obtained using quinacrine for staining. The pattern of bands is very similar to that seen in G-banding.They can be recognized by a yellow fluorescence of differing intensity. Most part of the stained DNA is heterochromatin. Quinacrin (atebrin) binds both regions rich in AT and in GC, but only the AT-quinacrin-complex fluoresces. Since regions rich in AT are more common in heterochromatin than in euchromatin, these regions are labelled preferentially. The different intensities of the single bands mirror the different contents of AT. Other fluorochromes like DAPI or Hoechst 33258 lead also to characteristic, reproducible patterns. Each of them produces its specific pattern. In other words: the properties of the bonds and the specificity of the fluorochromes are not exclusively based on their affinity to regions rich in AT. Rather, the distribution of AT and the association of AT with other molecules like histones, for example, influences the binding properties of the fluorochromes.
T-banding: visualize telomeres.
Silver staining: Silver nitrate stains the nucleolar organization region-associated protein. This yields a dark region where the silver is deposited, denoting the activity of rRNA genes within the NOR.

text: Classic karyotype cytogenetics[edit]

text: In the "classic" (depicted) karyotype, a dye, often Giemsa (G-banding), less frequently mepacrine (quinacrine), is used to stain bands on the chromosomes. Giemsa is specific for the phosphate groups of DNA. Quinacrine binds to the adenine-thymine-rich regions. Each chromosome has a characteristic banding pattern that helps to identify them; both chromosomes in a pair will have the same banding pattern.

text: Karyotypes are arranged with the short arm of the chromosome on top, and the long arm on the bottom. Some karyotypes call the short and long arms p and q, respectively. In addition, the differently stained regions and sub-regions are given numerical designations from proximal to distal on the chromosome arms. For example, Cri du chat syndrome involves a deletion on the short arm of chromosome 5. It is written as 46,XX,5p-. The critical region for this syndrome is deletion of p15.2 (the locus on the chromosome), which is written as 46,XX,del(5)(p15.2).[62]

text: Multicolor FISH (mFISH) and spectral karyotype (SKY technique)[edit]

text: Multicolor FISH and the older spectral karyotyping are molecular cytogenetic techniques used to simultaneously visualize all the pairs of chromosomes in an organism in different colors. Fluorescently labeled probes for each chromosome are made by labeling chromosome-specific DNA with different fluorophores. Because there are a limited number of spectrally distinct fluorophores, a combinatorial labeling method is used to generate many different colors. Fluorophore combinations are captured and analyzed by a fluorescence microscope using up to 7 narrow-banded fluorescence filters or, in the case of spectral karyotyping, by using an interferometer attached to a fluorescence microscope. In the case of an mFISH image, every combination of fluorochromes from the resulting original images is replaced by a pseudo color in a dedicated image analysis software. Thus, chromosomes or chromosome sections can be visualized and identified, allowing for the analysis of chromosomal rearrangements.[63] In the case of spectral karyotyping, image processing software assigns a pseudo color to each spectrally different combination, allowing the visualization of the individually colored chromosomes.[64]

text: Multicolor FISH is used to identify structural chromosome aberrations in cancer cells and other disease conditions when Giemsa banding or other techniques are not accurate enough.

text: Digital karyotyping[edit]

text: Digital karyotyping is a technique used to quantify the DNA copy number on a genomic scale. Short sequences of DNA from specific loci all over the genome are isolated and enumerated.[65] This method is also known as virtual karyotyping.

text: Chromosome abnormalities[edit]

text: Chromosome abnormalities can be numerical, as in the presence of extra or missing chromosomes, or structural, as in derivative chromosome, translocations, inversions, large-scale deletions or duplications. Numerical abnormalities, also known as aneuploidy, often occur as a result of nondisjunction during meiosis in the formation of a gamete; trisomies, in which three copies of a chromosome are present instead of the usual two, are common numerical abnormalities. Structural abnormalities often arise from errors in homologous recombination. Both types of abnormalities can occur in gametes and therefore will be present in all cells of an affected person's body, or they can occur during mitosis and give rise to a genetic mosaic individual who has some normal and some abnormal cells.

text: Chromosomal abnormalities that lead to disease in humans include

text:
Turner syndrome results from a single X chromosome (45,X or 45,X0).
Klinefelter syndrome, the most common male chromosomal disease, otherwise known as 47,XXY, is caused by an extra X chromosome.
Edwards syndrome is caused by trisomy (three copies) of chromosome 18.
Down syndrome, a common chromosomal disease, is caused by trisomy of chromosome 21.
Patau syndrome is caused by trisomy of chromosome 13.
Trisomy 9, believed to be the 4th most common trisomy, has many long lived affected individuals but only in a form other than a full trisomy, such as trisomy 9p syndrome or mosaic trisomy 9. They often function quite well, but tend to have trouble with speech.
Also documented are trisomy 8 and trisomy 16, although they generally do not survive to birth.

text: Some disorders arise from loss of just a piece of one chromosome, including

text:
Cri du chat (cry of the cat), from a truncated short arm on chromosome 5. The name comes from the babies' distinctive cry, caused by abnormal formation of the larynx.
1p36 Deletion syndrome, from the loss of part of the short arm of chromosome 1.
Angelman syndrome – 50% of cases have a segment of the long arm of chromosome 15 missing; a deletion of the maternal genes, example of imprinting disorder.
Prader-Willi syndrome – 50% of cases have a segment of the long arm of chromosome 15 missing; a deletion of the paternal genes, example of imprinting disorder.

text: Chromosomal abnormalities can also occur in cancerous cells of an otherwise genetically normal individual; one well-documented example is the Philadelphia chromosome, a translocation mutation commonly associated with chronic myelogenous leukemia and less often with acute lymphoblastic leukemia.