Genetics

• Assumptions - pop is large, randomly mating, not affected by mutation, migration, or natural selection
• Predictions - allelic fq dont change
• Predictions - genotypic fq stabalize after one generation of p² 2pq and q²
• Special note = assumptions only apply to single locus

Alleles of parents segregate independantly (mendelian genetics) therefore the fq of alleles in gametes will be the same as in parents.

• 1.) reproduction alone will not cause evolution
• 2.) When a pop us in HWE - genotypic fq are determined by allelic fq
• 3.) Single generation of random mating produces equilibrium fq.

• Must compare expected genotypic frequencies to observerd fq's
• 1.) determine allelic fq
• 2.) find expected genotypic fq by squaring allelic frequencies
• 3.) compare expected vs observed using chi sq test

• P and Q represent allele frequencies ie p=f(A) q=f(a)
• Genotype frequency is (p+q)² = p² + 2pq + q² = 1

• Positive assortative mating = tendency for like individuals to mate ie humans and height tall with tall... or inbreeding (different because affects all genes, not just determinate of trait of preference)
• Increases homozygosity
• Negative assortative mating = tendency for unlike individuals to mate ie tall with short... increases heterozygosity

• 1. Deviations due to phenotypic resemblance.
• 2. Deviations due to genetic relatedness.

• 1.) Inbreeding - creates increase in homozygous and decrease in heterozygous
• 2.) Outbreeding - avoidance of mating with related individuals (increases heterozygosity of pop)
• 3.) Genotypic fq change, allele fq do not

• 2. autozygosity: two alleles that are identical by descent.
• 3. allozygosity: two alleles that are NOT identical by descent

• the probability that the two alleles in an individual
• at a given gene are identical by descent (= probability of autozygosity.)

study of how genes, alleles, and chromosomes behave in populations

• Pedigrees that begin with a half-sib mating have one loop (pathway).
• Pedigrees that begin with a full-sib mating contain 2 loops (2 pathways).

• 1.) change in allelic frequency
• 2.) Evolution

• (mu)p-(v)p; where (mu) is forward mutation rate and (v) is reverse mutation rate
• as p --> q, (delta)q decreases because there are less
• p->q

• q= (mu)/((mu)+(v))
• p = (v)/((mu)+(v))
• def only by forward and reverse rates (not starting fq)
• genotypic fq stays same because in HW equilibrium

P_t is the allelic frequency after (t) generations experiencing mutation at rate (mu)

P_t = P₀(1-(mu))^t

• 1.) Prevents pop from becoming genetically unique (pop become more similiar) "great homogenizer"
• 2.) Increase genetic variation with in a pop.

1.) Both bring genetic variation to a pop, but migration is much faster