BIOL 1911 Lecture Notes - Lecture 23: Balancing Selection, Heterozygote Advantage, Mate Choice

21 views3 pages

Document Summary

If male gains mate, this benefit outweighs other risks caused by showiness, such as predation. Prey species guard against attack from whatever phenotype of scale-eating fish is most common in the lake. Thus, from year to year, selection favors which mouth phenotype is least common. Frequency of left and right mouthed fish oscillates over time. Keeps phenotype close to 50% (ii) heterozygote advantage. Individuals who are heterozygous at a particular locus have greater fitness than do both kinds of homozygotes. In this case, natural selection maintains two or more alleles at that locus: defined in terms of genotype, not phenotype, whether heterozygote advantage represents stabilizing or directional selection depends on the relationship between genotype and phenotype. If phenotype of a heterozygote is intermediate to the phenotypes of both homozygotes, heterozygote advantage is a form of stabilization selection: ex: heterozygotes for the sickle-cell allele are protected against malaria.

Get access

Grade+
$40 USD/m
Billed monthly
Grade+
Homework Help
Study Guides
Textbook Solutions
Class Notes
Textbook Notes
Booster Class
10 Verified Answers
Class+
$30 USD/m
Billed monthly
Class+
Homework Help
Study Guides
Textbook Solutions
Class Notes
Textbook Notes
Booster Class
7 Verified Answers

Related Documents

Related Questions