Population Genetics 3 & 4

Question 1

Gene Flow

Answer 1

the movement and incorporation of genes from one population into the gene pool of another population

Question 2

How do populations become subdivided?

Answer 2

1. individuals may migrate to new locations and found new subpopulation
2. exisiting populations may become fragmented by newly arising barriers
3. distant poinyts in a species

Question 3

Isolated subpop become genetically differentiated by genetic drift

Answer 3

• drift happens independently in each subpopulation
• independent drift causes the populations to diverge in allele frequencies.

Question 4

Fst - variance in allele frequency among sub populations

Answer 4

• ranges from 0 to 1
  if all subpopulations have identical allele frequencies, fst = 0
  if all subpopulations are fixed for different alleles, fst =1
  partially isolated subpopulations have 0 < Fst < 1

Question 5

Gene Flow causes subpopulations to become more similar to each other. Gene flow is a homogenizing force

Answer 5

• very small m, means that subpopulations will diverge through drift
• with large m, the subpopulations become like a single completely mixing population.

Question 6

Habitat Fragmentation

Answer 6

this causes bottlenecks , creates small isolated populations and can lead to genetic drift