Population Genetics & Epidemiology Flashcards

Hardy-Weinberg equilibrium requires which of the following conditions?

Answer: Random mating, no mutation, no migration, no selection, and large population size

Hardy-Weinberg equilibrium is maintained in large, randomly mating populations free of mutation, migration, and selection pressure.

In a population where the frequency of a recessive allele (q) is 0.1, the expected carrier frequency under Hardy-Weinberg equilibrium is:

Answer: 0.18 (18%)

Carrier frequency = 2pq = 2 × 0.9 × 0.1 = 0.18, meaning 18% of the population are heterozygous carriers.

The founder effect in genetics refers to:

Answer: Reduced genetic diversity in a population descended from a small founding group

The founder effect occurs when a small isolated group establishes a new population, leading to high frequencies of alleles present in the original founders.

Genetic drift is MOST significant in:

Answer: Small, isolated populations

Genetic drift causes random fluctuation in allele frequencies that is most pronounced in small populations where chance events have a larger proportional impact.

Which term describes the increased frequency of a condition in offspring of consanguineous couples compared with the general population?

Answer: Autozygosity

Autozygosity refers to inheriting identical-by-descent alleles from a common ancestor, which increases the risk of homozygosity for recessive pathogenic variants in consanguineous offspring.

The concept of 'heterozygote advantage' explains the persistence of cystic fibrosis alleles in European populations through the hypothesis that:

Answer: CF carriers may have had increased resistance to certain infectious diseases such as cholera

One hypothesis for the persistence of CFTR variants is that carriers may have had a survival advantage against chloride-depleting infections like cholera.