Abstracts (first author)
Interplay of gene conversion and crossover in the molecular evolution of multigene families
Multigene families are part of the pervasive Structural Variation (SV) present in eukaryotic genomes. In humans, regions with SV have been associated to disease and have been shown to participate in evolutionary innovation. Despite its widespread abundance and functional relevance, an accurate description of the underlying forces shaping the evolution of these regions is still lacking. In particular, the proper characterization of the interplay between mutation, crossover and gene conversion in multigene families is fundamental. We have developed a forward-time simulation program that incorporates duplications and focuses on the effect of concerted evolution (the non-independent evolution of duplicated regions). By means of simulations, we have explored a wide range of parameters, gaining insight into the evolution of regions under concerted evolution such as the MHC. First, we observe that neutral concerted evolution can confound scans for selection by mimicking the effects of both weak purifying selection or weak positive selection. These effects can be more pronounced if duplicated regions are collapsed, as is frequent in low-quality genome assemblies. Additionally, we explore the effects of crossover hotspots in duplicated regions that present gene conversion activity. Our results show that multigene-family evolution is highly dependent on the spatial distribution of crossover and gene conversion events and their rates, even under neutrality.