Heterogeneity of genetic architecture of body size traits in a free‐living population

A groundbreaking study on St Kilda's Soay sheep reveals stark differences in the genetic architecture of body size traits. While jaw and weight exhibit polygenic inheritance—with multiple chromosomes contributing to variance without specific SNPs driving significant phenotypic changes—leg length traits (foreleg, hindleg, metacarpal) are dominated by two key SNPs on chromosomes 16 and 19, each explaining over 10% of additive genetic variance. Heterozygous females for one SNP (s74894.1) outperform homozygous counterparts in lamb production and recruitment, hinting at fitness advantages. The research also traces shorter leg alleles to historic admixture with Dunface sheep, underscoring how dense SNP panels can unravel selection pressures and evolutionary history in wild populations.

Bérénos, C., Ellis, P. A., Pilkington, J. G., Lee, S. H., Gratten, J., & Pemberton, J. M. (2015). Heterogeneity of genetic architecture of body size traits in a free‐living population. Molecular Ecology, 24(8), 1810–1830. Portico. https://doi.org/10.1111/mec.13146