Examples of Genetic Drift, Gene Flow & Selection

Genetic Drift – nonselective & random

Founder Effect Bottle Neck Effect

When a few individuals become isolated from large population establishing a new population.

The new population’s gene pool differs from the original

Sudden change in environment drastically reduces the size of a population

By chance alone alleles represented are different from the original population

Northern Elephant Seal

http://evolution.berkeley.edu/evosite/evo101/IIID3Bottlenecks.shtml

Achromatopsia – Pingelap Atol

http://islander01.weebly.com/

http://curiositychronicles.tumblr.com/post/6108866789/curious-about-achromatopsia

http:/www.color-blindness.com/2011/11/14/living-with-total-color-blindness-documentary-island-of-the-colorblind//

Deafness on Martha’s Vineyard

http://www.sorensonvrs.com/aware2012_preserving

http://historytrendsanddeafeducation.pbworks.com/w/page/18570645/Martha's%20Vineyard

Jonathan Lambert, 1694

Polydactyly in Amish

http://nell-rose.hubpages.com/hub/Polydactyly-The-curious-Congenital-Anomaly-found-In-Humans

Type O blood in American Indians

http://anthro.palomar.edu/synthetic/synth_5.htm

Gene Flow

The transfer of alleles into or out of a population due to the movement of fertile individuals or their gametes

Gene Flow in Plants

http://bch.cbd.int/cpb_art15/training/module3.shtml

Gene Flow in Humans

http://www.bbc.com/news/magazine-27159697

“Thousands of children were fathered by American Servicemen during the Vietnam war.”

Gene Flow between Animals

http://www.sciencedaily.com/releases/2011/05/110525131711.htm

Selection

Consistently increasing the frequency of alleles that provide reproductive advantage and thus lead to adaptive evolution

Stabilizing Selection

https://darwinbookcats.wordpress.com/2011/06/22/stabilizing-selection-and-a-stable-environment/

Directional Selection

http://legacy.hopkinsville.kctcs.edu/instructors/Jason-Arnold/VLI/Module%203/Module3Evolution/Module3Evolution8.html

Disruptive Selection

https://www.studyblue.com/notes/note/n/test-1-set-8-evolutionary-processes/deck/1100896

Sexual Selection

Intersexual (mate choice)

Intrasexual (competition)

http://wallace.genetics.uga.edu/groups/evol3000/wiki/543e6/Sexual_SelectionConflict.htmlhttp://www.zoology.ubc.ca/~otto/PopGen500/

Discussion3/Overheads.html

Balancing Selection

Heterozygote Advantage

Frequency-Dependent Selection

http://biology-forums.com/index.php?action=gallery;sa=view;id=696

http://bio.research.ucsc.edu/~barrylab/classes/evolution/NS_H2.HTM