A copy number variant is associated with a spectrum of pigmentation patterns in the rock pigeon ( < i > Columba livia < /i > )

by Rebecca Bruders, Hannah Van Hollebeke, Edward J. Osborne, Zev Kronenberg, Emily Maclary, Mark Yandell, Michael D. Shapiro

Rock pigeons (Columba livia) display an extraordinary array of pigment pattern variation. One such pattern, Almond, is characterized by a variegated patchwork of plumage colors that are distributed in an apparently random manner. Almond is a sex-linked, semi-dominant trait controlled by the classicalStipper (St) locus. Heterozygous males (ZStZ+ sex chromosomes) and hemizygous Almond females (ZStW) are favored by breeders for their attractive plumage. In contrast, homozygous Almond males (ZStZSt) develop severe eye defects and often lack plumage pigmentation, suggesting that higher dosage of the mutant allele is deleterious. To determine the molecular basis of Almond, we compared the genomes of Almond pigeons to non-Almond pigeons and identified a candidateSt locus on the Z chromosome. We found a copy number variant (CNV) within the differentiated region that captures complete or partial coding sequences of four genes, including the melanosome maturation geneMlana. We did not find fixed coding changes in genes within the CNV, but all genes are misexpressed in regenerating feather bud collar cells of Almond birds. Notably, six other alleles at theSt locus are associated with depigmentation phenotypes, and all exhibit expansion of the same CNV. Structural variation atSt is linked to diversity in plumage pigmentation and gene expression, and thus provides ...

Source: PLoS Genetics - May 19, 2020 Category: Genetics & Stem Cells Authors: Rebecca Bruders Source Type: research