Studies of hybridization between model organisms have been extremely important to our understanding of the formation of new species, but are unlikely to fully capture how speciation and hybridization proceed in natural systems. In the proposed project, the researchers investigate the genetic basis of reproductive isolation between Indigo (Passerina cyanea) and Lazuli (P. amoena) buntings (Aves: Cardinalidae), which form a hybrid zone where their breeding ranges overlap. Preliminary data suggest that different genetic loci (mitochondrial, nuclear autosomal, nuclear Z-linked) exhibit differential introgression across the hybrid zone and implicate the Z-chromosome as having a relatively large impact on avian speciation. Here, patterns of genetic introgression of multiple Z-linked loci will be combined with theoretical predictions to test hypotheses aimed at identifying genes contributing to reproductive isolation between these species.
Beyond the impact the research will have on our understanding of the evolution of reproductive isolation between closely related species, the data collected will also allow for assessments of range expansion in P. cyanea. Observational data suggests the breeding range of P. cyanea is expanding westward, perhaps at the expense of P. amoena, such that an accurate knowledge of the patterns of hybridization between them may be important for conservation purposes.
