33 Oral - Platform Session #3 Speciation, Hybridization, and Introgression
Thursday June 09, 10:50 AM - 11:05 AM
Replicate hybrid populations reveal shared genome evolution across multiple species
Authors: Quinn Langdon 1,2; Daniel Powell 1,2; Molly Schumer 1,2,3
Affiliations: 1) Stanford University, Stanford, California; 2) Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C., Calnali, Mexico; 3) Hanna H. Gray Fellow, Howard Hughes Medical Institutes, Chevy Chase, Maryland, United States of America
Keywords: Comparative genomics & genome evolution
Hybridization is ubiquitous across the tree of life. With whole-genome sequencing we have revealed evidence for hybridization across scales; from ancient to recent and between closely and distantly related species. Our own species harbors genomic regions that are derived from hybridization. We are now entering an era where we can determine the mechanisms underlying hybrid genome stabilization and how these are shared across hybridization events. A powerful system to address these questions is in the swordtail fish genus Xiphophorus, where replicate hybrid populations of two species pairs (X. birchmanni × X. cortezi and X. birchmanni × X. malinche) have allowed us to identify predictable factors driving genome stabilization in hybrids. We find high levels of repeatability in ancestry across the genomes of these populations despite their independent origins. This can be attributed in part to shared broad scale genomic organization. This includes a shared recombination landscape and shared locations of coding and conserved basepairs. With the discovery of additional hybrid populations between X. birchmanni × X. cortezi, we are beginning to disentangle the relative roles of different sources of selection in shaping ancestry across the genome. Our results highlight an important role for adaptively introgressed elements and hybrid incompatibilities that are shared across multiple species. Together these findings of parallel evolution after hybridization have important implications for mechanisms shaping hybrid genomes across the tree of life.