Study of the role of sexual selection in the speciation process of the southern capuchinos (genus Sporophila)

CAMPAGNA, LEONARDO; TUBARO, PABLO L.; RODRÍGUEZ-CAJARVILLE, MARÍA J.; LIJTMAER, DARÍO A.; ESTALLES, CECILIA; LOVETTE, IRBY

Congreso; AOS Meeting 2019; 2019

The southern capuchinos constitute a recent radiation of ten sympatric South American avian species of the genus Sporophila, which differ phenotypically (color and song) but do not diverge in their neutral genetic content. Recent analyses showed that some of these species do differ in few areas of the genome related to the melanogenesis pathway, presumably as a consequence of sexual selection. Particularly, S. hypoxantha and S. ruficollis only differ in the presence of a black plumage patch on the throat of the latter, and are therefore an ideal pair of species to study the speciation process and the role of sexual selection in the group. We analyzed the complete genome for 15 S. ruficollis and 12 S. hypoxantha individuals. Only few areas of the genome differed between species. Moreover, under a strict criterion, only two areas presented significant divergence between species, showing that these are the less differentiated capuchino species. These areas include the genes HERC2 and TYRP1, which are involved in coloration. Analyses using the entire genome could not differentiate the two species, which could only be separated by their peaks of divergence. These results confirm that these two species are in an early stage of the speciation process, still lack neutral genomic differentiation and are only separated by two coloration genes that could be responsible for the different color of their throats. Behavioral experiments linking these findings with species recognition and mate choice are underway to further assess the role of sexual selection in the speciation process.