ROLE OF GENE INTERACTIONS IN HYBRID SPECIATION - EVIDENCE FROM ANCIENT AND EXPERIMENTAL HYBRIDS

The origin of a new diploid species by means of hybridization requires the successful merger of differentiated parental species' genomes. To study this process, the genomic composition of three experimentally s ynthesized hybrid lineages was compared with that of an ancient hybrid species. The genomic composition of the synthesized and ancient hybri ds was concordant (r(s) = 0.68, P < 0.0001), indicating that selection to a large extent governs hybrid species formation. Further, nonrando m rates of introgression and significant associations among unlinked m arkers in each of the three synthesized hybrid lineages imply that int eractions between coadapted parental species' genes constrain the geno mic composition of hybrid species.