Population Structure Flashcards
Does inbreeding increase or decrease phenotypic variation?
Increases - it reduces heterozygosity.
What is genetic drift? How does population structure affect this?
Random changes in gene frequency. Demographics, proximity and population size affect the rate and magnitude of gene frequency change.
If genetic differences aren’t caused by adaptation, what could they be caused by?
A mix of drift and fixation of neutral alleles. Drift and selection can happen simultaneously.
What is the effective population size?
The number of individuals who can contribute offspring to the next generation.
What is the founder effect?
The reduced genetic diversity that results when a population is descended from a small number of colonizing ancestors.
How does inbreeding increase variation in a population?
Inbreeding causes homozygous subpopulations, and the variation among subpopulations exceeds variation within populations, enough to increase variation.
How is genetic variation at a given locus lost? What process is this an example of?
Gene frequencies can fluctuate by chance in a population, until one allele or another becomes fixed and the variation is lost.
This is a form of genetic drift.
What is migration and how does it affect genetic variation and genetic drift? How does it affect speciation?
The flow of genes among populations.
It increases genetic variation and counteracts genetic drift.
It increases genetic cohesion in a population and lessens the potential for speciation because it prevents precise adaptation to the specific environment.
