Genetic Subdivisions

What is the definition of inbreeding?

Mating between relatives

What is the relationship between inbreeding and homozygosity?

As inbreeding increases, so does the rates of homozygosity

What is the difference between assortative mating and inbreeding?

While both decrease heterozygosity, associative mating will only affect certain genetic loci, while inbreeding affects all

What is the variable "F"?

Inbreeding coeffecient

What is Ho?

Random mating heterozygosity

What is H?

Actual frequency of heteozygotes within an inbreeding population

What is the equation for the inbreeding coeffecient?

(Ho-H)/Ho

What is the definition of the inbreeding coeffecient?

Describes the fractional reduction in heterozygosity relative to a population that's randomly mating

What is the equation for the actual frequency of heterozygotess within an inbreeding population?

H=2pq(1-F)

What does a F=1 suggest?

Complete inbreeding

What is the equation for homozygotes within an inbreeding population?

p^2 + pF(1-p)

What is the definition of F in terms of probability?

F is the probability that two alleles of a gene in a single individual are identical by descent

What is another term for when genes are identical by descent?

autozygous

Autozygous individuals must be _____________

homozygous

Allozygous individuals may be ____________

homozygous or heterozygous

How is "identical by state" different than "identical by descent"

IBS refers to the chemical makeup while IBD refers to ancestral origin

What is the difference between allozygous and autozygous?

Allozygous alleles come from different sources while autozygous alleles orriginate from a common ancestor

What are the steps for calculating the inbreeding coeffecient from a pedigree?

Locate all common ancestors. Trace a paths to gametes from common ancestors back down to the individual. Each step will be 1/2, except for the common ancestor

What is the equation for the common ancestor?

1/2 (1-Fa)

Why is the equation for the common ancestor different?

We must consider whether the common ancestor was also inbred

What is the equation for an allozygote allele?

(1-F)

What is the equation for an autozygote allele?

F

How is inbreeding typically studied?

Through self-fertilizing plants

What is the Wahlund Affect?

Causes a percieved deficiency in heterozygotes, but arises from treating two separate populations as one. Caused by different populations having different alelle frequencies.

What are the three levels of subcomplexity within a sub-structured population?

Individual, subpopulation, total population

What is HI

Average actual observed heterozygosity of all genes in an individual. AKA: probability of heterozygosity at any gene/locus

What is HS

Represents the heterozygosity within a sub-population during random mating.

What is HT

Represents the heterozygosity if all subpopulations were pooled together and mated randomly

What is the fixation index?

Fst. Represents the decrease in heterozygosity in a subpopulation due to random genetic drift

What is Fis

Inbreeding in individuals relative to the subpopulation

What is Fst?

Inbreeding in subpopulations relative to the whole population

What is Fit?

Inbreeding in individuals relative to the entire population

What is the most inclusive measure of inbreeding? Why?

Fit. Takes into account nonrandom mating within subpopulations and effects of population subdivision

What is the equation for Fis?

(Hs-Hi)/Hs

What is the equation for Fst?

(Ht-Hs)/Ht

What is the equation for Fit?

(Ht-Hi)/Ht

What is the mathematical relationship between Fis/Fst/Fit?

(1-Fis)(1-Fst)=(1-Fit)

Why is the fixation index (Fst) a good estimate of the total inbreeding coefficient within humans?

In humans, Fis is usually 0. This means that Fst=Fit

How can Fis=0 even if there is inbreeding within a subpopulation?

Ass long as the inbreeding does not exceed the expected amount for a cerain population according to random mating it will still be zero

What is the relationship between F and genetic drift?

As genetic drift occurs, F will increase

What measurement is used to determine the genetic differences among populations?

Fst

What will influence the values of Fst?

genetic drift, migration, natural selection, mutation

What amount of genetic variation in humans is ascribable to genetic differences between population groups?

7%