Meiotic, genomic and evolutionary properties of crossover distribution in Drosophila yakuba

Clonal ants reveal a potentially hidden meiotic feature

Meiosis is essential for eukaryotic reproduction and provides the basis for Mendel's segregation laws. A recent study by Lacy et al. identified a significant deviation from these laws in a clonal ant, hinting at a potentially overlooked meiotic feature. This discovery may have broader implications for recombination in nonclonal eukaryotes.

Background selection under evolving recombination rates

Background selection (BGS), the effect that purifying selection exerts on sites linked to deleterious alleles, is expected to be ubiquitous across eukaryotic genomes. The effects of BGS reflect the interplay of the rates and fitness effects of deleterious mutations with recombination. A fundamental assumption of BGS models is that recombination rates are invariant over time. However, in some lineages, recombination rates evolve rapidly, violating this central assumption. Here, we investigate how recombination rate evolution affects genetic variation under BGS. We show that recombination rate evolution modifies the effects of BGS in a manner similar to a localized change in the effective population size, potentially leading to underestimation or overestimation of the genome-wide effects of selection. Furthermore, we find evidence that recombination rate evolution in the ancestors of modern house mice may have impacted inferences of the genome-wide effects of selection in that species.