Neutral Theory of Molecular Evolution and Genetic Drift

These flashcards cover key concepts related to the Neutral Theory of Molecular Evolution and the role of genetic drift in shaping genetic variation.

What is the primary role of genetic drift in molecular evolution according to the Neutral Theory?

Drift plays a major role in DNA and protein evolution by influencing the fixation of neutral mutations.

How does the neutrality of mutations affect their persistence in a population?

Most mutations are neutral and become fixed or lost in a population through the process of genetic drift.

What does nucleotide diversity indicate regarding introns and exons in a genome?

DNA polymorphisms (SNPs) are more common in introns than in exons due to less selective pressure on intronic regions.

Why are synonymous mutations more common than non-synonymous mutations?

Synonymous mutations do not change the amino acid sequence, thus they are less likely to be purged by selection.

What is the fixation rate of new mutations relative to neutral mutation rate?

The fixation rate of new mutations equals the neutral mutation rate (u0), with actual rates often higher than observed due to limited substitution opportunities.

What is the significance of centromeres and telomeres in terms of nucleotide diversity?

Nucleotide diversity is lowest at centromeres and telomeres due to intense selection pressures and structural constraints.

What is a molecular clock and how is it estimated?

A molecular clock is estimated by counting differences among sequences and using the mutation rate to infer the time to a common ancestor.

How does population size affect genetic drift and mutation fixation?

Drift operates more rapidly in smaller populations, influencing the time to fixation or extinction of mutations.

What is the relationship between genetic drift and the Null hypothesis in population genomics?

Genetic drift serves as a basis for the Null hypothesis in explaining patterns of genetic variance in population genomics.

What does the concept of selective sweeps imply for population genetics?

Selective sweeps can mimic changes in DNA sequences, complicating the estimation of effective population size (Ne).