Evolution of a large population under gene conversion

Area of Science:

• Population Genetics
• Molecular Evolution
• Genetics

Background:

• Gene conversion is a non-reciprocal transfer of genetic information between homologous DNA sequences.
• Allelic frequencies in populations are influenced by evolutionary forces like mutation, selection, drift, and recombination.
• Understanding gene conversion dynamics is crucial for explaining genetic variation and divergence.

Purpose of the Study:

• To investigate the impact of biased gene conversion on allelic frequencies at a single multiallelic locus.
• To determine the conditions under which gene conversion can lead to allele loss and reduced genetic variability.
• To assess the role of biased gene conversion in the genetic divergence of isolated populations.

Main Methods:

• Analytical investigation of allelic frequency dynamics.
• Numerical simulations to model gene conversion processes.
• Consideration of discrete, non-overlapping generations in a randomly mating diploid population.
• Negligible selection, mutation, and random genetic drift were assumed.

Main Results:

• Biased gene conversion within any pair of alleles inevitably drives at least one allele frequency toward zero.
• If conversion is biased across all allele pairs, only one allele can potentially persist.
• Random genetic drift ensures the ultimate loss of alleles, even if frequencies fluctuate.
• The rate of genetic variability decay suggests biased gene conversion is a significant factor in population divergence.

Conclusions:

• Biased gene conversion is a potent evolutionary force capable of reducing genetic diversity within populations.
• This mechanism can lead to the fixation of one allele or the loss of all but one allele.
• Biased gene conversion can accelerate the genetic divergence between isolated populations, impacting speciation processes.