Spatial Genetic Variation

Question 1

What is population structure? Is this a mechanism of change, or a description of a pattern?

Answer 1

the pattern of distribution of different groups within a population, describing how individuals are organized and differentiated within a species.

Question 2

What are the causes of genetic structure among populations?

Answer 2

natural selection, mutation, random genetic drift, and migration into or out of the population

Question 3

Why is population structure like inbreeding? Why is it NOT inbreeding?

Answer 3

-like inbredding, population structure leads to a loss of heteozygosity
**the loss is hypothetical in the case of population structure

Question 4

What is FST?

Answer 4

• a measure of population differentiation due to genetic structure. Frequently estimated from genetic polymorphism data, such as single nucleotide polymorphisms (SNT)
  → Based on the variance of allele frequencies between populations and on the probability of identity by descent

Question 5

What is the impact of genetic drift on population structure?

Answer 5

causing a random change in allele frequencies, leading to a decrease in genetic diversity within a population, potentially causing certain alleles to become fixed or completely lost, and ultimately increasing genetic differentiation between isolated populations due to these random fluctuations in allele frequencies, particularly in small populations

Question 6

What is the impact of migration (m) on patterns of population structure?

Answer 6

• migration makes populations more similar to one another. In the absence of any other evolutionary processes, migration will completely homogenize subpopulations

Question 7

What is drift/migration equilibrium?

Answer 7

a balance in a population where the forces of genetic drift (random changes in allele frequencies due to chance events) are counteracted by the introduction of new alleles through migration

Question 8

What is the “One migrant per generation” rule? Why is it important? Why is it too simple?

Answer 8

The “One migrant per generation” rule is a concept in population genetics that states that introducing just one individual from a different population into a given population each generation is enough to maintain genetic diversity and prevent harmful inbreeding within that population, effectively acting as a safeguard against genetic drift; it’s considered important for conservation efforts, especially when managing small, isolated populations, but is considered “too simple” because it relies on many simplifying assumptions that may not always be true in real-world situations