Total consensus under high reproductive-variance conditions

TL;DR

This paper investigates how high reproductive variance in marine species affects genetic diversity, revealing that populations maintain some heterozygosity despite extreme reproductive events, with implications for understanding genetic decline.

Contribution

It introduces a model assuming Pareto-distributed reproduction to analyze heterozygosity distribution under high reproductive variance, highlighting deviations from classical models.

Findings

Zero heterozygosity is not achieved in high-variance populations.

Singularities exist in heterozygosity distributions under extreme reproductive conditions.

Deviations from Wright-Fisher model predictions are observed in the locations of singular points.

Abstract

Star-shaped branching patterns of genealogies are common in marine species. High-fecundity marine populations are characterized by low ratios of effective to actual population size, which reflect high variance in reproductive success among parents in mass spawns. When extreme reproduction events occur, offspring from very few parents dominate the population (whereby multiple mergers, or subsets of lineages with star-like trees, arise) and thus, the loss of genetic diversity is significant. Under high reproductive-variance conditions (assuming that reproduction occurs by sampling from the Pareto distribution), this paper explores the distribution of heterozygosity across generations. The result shows that zero heterozygosity is not achieved, implying that the populations may decline without evident loss of genetic variation. It is also found that there are singularities in the heterozygosity distributions. However, in the case of high reproductive variance, the locations of the singular points subtly deviate from those of the case where reproduction occurs by Wright-Fisher sampling.