Searching for the genomic basis of differentiation in plumage patterning within the Rufous-collared Sparrow (Zonotrichia capensis).

LAVINIA OBLANCA PABLO DAMIÁN; CAMPAGNA LEONARDO; BARREIRA ANA S.; LOUGHEED, STEPHEN C.; TUBARO PABLO LUIS; LIJTMAER DARÍO A.

Virtual (Covid-19)

Congreso; VII North American Ornithological Conference; 2020

High-throughput sequencing is allowing researchers to unveil the genomic basis behind plumage color differentiation. The Rufous-collared Sparrow (Zonotrichia capensis) shows phenotypic variation throughout its distribution. In particular, Z. c. australis from southern Chile and Argentina differentiates from other subspecies by lacking the characteristic black lateral crownstripes (i.e., head uniformly grey or with only subtle traces of black). We sequenced whole genomes of 18 individuals (9 representing Z. c. australis and 9 from northcentral Argentina possessing the black crownstripes) to investigate the genomic changes behind this phenotypic differentiation. Based on the analysis of ~ 11 million SNPs, we detected three divergence peaks that contrast with a background of low genomic differentiation (FST = 0.015  0.018) between Z. c. australis and the other individuals. Differentiation at these three peaks combined (1,350 SNPs) was remarkably higher (FST = 0.29  0.09). However, 90% of outlier SNPs (211/235 SNPs with an FST  0.8) and virtually all fixed differences (51/53 SNPs with an FST = 1) were located within a single ~200-kb region mapped to chromosome 5. Outlier SNPs were concentrated within and downstream the Suppression of tumorigenicity 5 gene (ST5), which is involved in cytoskeletal organization and tumorigenicity in humans but has no characterized function in birds. Our results point out to ST5 as a gene of large effect controlling phenotypic differences between Z. c. australis and other subspecies, proposing this region with no previous association with pigmentation as a candidate gene for plumage color patterning.