reeding if population is finite, and mating is random, th is some probability of mating with a relative effects of small population size, mating with related individuals are similar drift, inbreeding, population subdivision all reduce within population genetic variance more likely if population size is small consequence is assortative mating over entire gen --deviations from expected heterozygosity (vs. HWE expectations) over all genes
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Inbreeding if population is finite, and mating is random, there is some probability of mating with a relative effects of small population size, mating.
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Inbreeding
if population is finite, and mating is random, there is some probability of mating with a relative
effects of small population size, mating with related individuals are similar
drift, inbreeding, population subdivision all reduce within population genetic variance
more likely if population size is small
consequence is assortative mating over entire genome --deviations from expected heterozygosity (vs. HWE expectations) over all genes
A1A2 A1A2
A1A2A1A2
A1A1
F = inbreeding coefficient = probability that an individual that is homozygous carries two alleles that are identical by descent, i.e., from a common ancestor
when a population is totally outbred, F = 0when a population is totally inbred, F = 1
look at one locus, consider an individual who is A1A1
1) random combination from unrelated parents2) identical by descent (both A1 alleles from a
Calculating Inbreeding Coefficients from Genealogies
What is the chance of a individualBecoming homozygous due to alleles From the same source?p = 1/2
p = 1/2
p = 1/2
p = 1/2
Chance of all events occurring = (1/2) 4
However, there are four possible alleles that could beMade homozygous due to inbreeding, therefore the Probability of homozygosity due to inbreeding is 4(1/2) 4 = 1/4
Inbreeding coefficient
A1A2
A1
A1A1
A1
The chance of events occurring is again (1/2) 4
However, only two possible pathwaysInbreeding coefficient = 1/8