BIOL 1010 Lecture Notes - Lecture 4: Allele Frequency, Genetic Drift, Genetic Diversity

46 views5 pages
29 Nov 2015
Department
Course
Professor

Document Summary

Hardy- weinberg principle: assumed a very large population. Sampling error" can lead to fixation (or extinction) of alleles in the absence of natural selection. Rate of drift related to population size. Natural allele frequency at 0. 5 is equally likely to eventually be fixed or to go extinct. [in theory, chance of eventual fixation of a natural allele is the same as its frequency] *genetic drift can overwhelm selection in small populations* Consider a locus with 2 alleles- r and w. Initial frequencies of r= 0. 8; of w= 0. 2. Each copy of w: fitness 5% higher than for r. W has 100% chance of eventually being fixed. W has <40% chance of eventually being fixed. Breeding population is very small for a time. Genetic drift powerful: allele frequencies change, many alleles fixed or go extinct. = lower genetic diversity overall, even if population later expands in numbers. Some rare alleles can increase in frequency.

Get access

Grade+20% off
$8 USD/m$10 USD/m
Billed $96 USD annually
Grade+
Homework Help
Study Guides
Textbook Solutions
Class Notes
Textbook Notes
Booster Class
40 Verified Answers
Class+
$8 USD/m
Billed $96 USD annually
Class+
Homework Help
Study Guides
Textbook Solutions
Class Notes
Textbook Notes
Booster Class
30 Verified Answers

Related Documents

Related Questions