ch 18 genetics terms
Card Set Information
ch 18 genetics terms
biol 350 genetics terms
proportion of alleles in a population of a particular type
# of copies of allele x/ total # of alleles
proportion of individuals in a population with a particular genotype
Hardy_weinberg genotype frequencies
Mutation is not occurring
Natural selection is not occurring
The population is infinitely large
All members of the population breed
All mating is totally random
Everyone produces the same number of offspring
There is no migration in or out of the population
positive assortative mating
bias of mating like with like; mate choice is dependent on resemblance to self. This is a source of reproductive isolation, as there is an excess of homozygotes at relevant loci
negative assortative mating
mating with unlike partners. Excess of heterozygotes at relevant loci
mating between relatives. Increases the probability of homozygosit at all loci. This can lead to a reduction in vigor and reproductive success, or inbreeding depression.
inbreeding coefficient (F)
the probability that two alleles in an individual trace back to the same copy in a common ancestor.
ultimate source of variability
gene flow; creates genetic admixtures
generates new haplotypes and breaks down linkage disequilibrium
random changes in allele frequencies from generation to generation; due to finite size of real populations; decreases genetic variation
genetic drift due to random sampling of a population to create a new population; many rare alleles are lost , whereas some rare alleles increase in frequency
relative contribution of an individual or genotypee to the next generation compared to another individual or genotype.
frequency of an allele moves in one direction until lost or reaching fixation; decreases diversity
increases frequency of beneficial alleles
eliminates deleterious alleles
maintains allele frequencies at an equilibriium point; maintains diversity when a heterozygous genotype is favored
How do the following affect diversity?
A) increase genetic diversity
C) increase haplotype diversity
D) reduced diversity (randomly)
E) either reduces or maintain diversity
What are the forces that can change the frequency of an allele in a population?
natural selection, mutation, migration, and genetic drift