Multiple (but few) genes are associated with differences in a color trait in the rapid capuchino radiation

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

Congreso; VII North American Ornithological Conference (virtual); 2020

American Ornithological Society y otras 6 sociedades de ornitología de América

New sequencing technologies have revolutionized our understanding of the genetic basis of avian plumage coloration and its role in the speciation process. The southern capuchinos (genus Sporophila) are an ideal study system to explore this connection. This group consists of ten species that have very low genetic differentiation and vary almost exclusively in plumage coloration. The few divergent areas of their genomes are associated with pigmentation genes. However, because many plumage patches vary at the same time in this group, direct associations between genes and specific coloration patches have not yet been established. S. hypoxantha, S. palustris and S. ruficollis differ in a single coloration patch, the throat (cinnamon, white and black, respectively), while S. iberaensis differs in other coloration patches but shares a black throat with S. ruficollis. Here we compared whole-genome sequences of 58 individuals from these four capuchino species with the objective of elucidating the genetic underpinnings of throat coloration. We found a strikingly low level of genomic differentiation, restricted to three genomic regions, among S. hypoxantha, S. palustris and S. ruficollis. These regions included genes associated with coloration and are therefore candidates for determining throat color in the group. S. iberaensis differed from S. hypoxantha and S. palustris, but not S. ruficollis, in the same genomic regions associated with throat coloration. Taken together, our results are consistent with the idea that throat coloration is a polygenic trait that has contributed through sexual selection to the rapid capuchino radiation in the grasslands of South America.