Skip to main content Accessibility help
×
Hostname: page-component-7c8c6479df-7qhmt Total loading time: 0 Render date: 2024-03-29T09:29:25.828Z Has data issue: false hasContentIssue false

7 - Phenotypic Change in Experimental Lineages

Published online by Cambridge University Press:  29 April 2019

Philip D. Gingerich
Affiliation:
University of Michigan, Ann Arbor
Get access

Summary

Analysis of 14 selection experiments in 8 published studies yields 672 step rates quantifying high- and low-line selection from one generation to the next. The median step rate for this sample, in haldanes, is h0 = 0.33 standard deviations per generation on a time scale of one generation. High-line experiments selecting for increases in trait value yield virtually the same rates as low-line experiments selecting for decreases in trait value, with median h0 values of 0.32 and 0.35, respectively. Both are near the selection median of h0 = 0.33. Control lineages not subject to experimental selection have a median h0 = 0.23. Control lineages with a substantial number of generations have temporal scaling slopes showing that they are stationary rather than random, which is attributable to stabilizing natural selection. What separates stationary lineages responding to stabilizing selection from directional lineages responding to directional selection is the pattern of change in their signs. Step rates observed in selection experiments (high lines, low lines, and control lines) exceed ‘null’ rates expected for purely random change by factors ranging from 2 to 100.
Type
Chapter
Information
Rates of Evolution
A Quantitative Synthesis
, pp. 124 - 156
Publisher: Cambridge University Press
Print publication year: 2019

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Save book to Kindle

To save this book to your Kindle, first ensure coreplatform@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.

Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

Find out more about the Kindle Personal Document Service.

Available formats
×

Save book to Dropbox

To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.

Available formats
×

Save book to Google Drive

To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.

Available formats
×