Genetics of Rapid and Extreme Size Evolution in Island Mice

House mice on Gough Island have evolved the largest body size among wild populations within just a few hundred generations, primarily through accelerated growth during the first six weeks of life. Researchers identified 19 quantitative trait loci (QTL) linked to body weight and growth rate by comparing these mice with a smaller-bodied subspecies using genetic mapping in F2 intercrosses. While the effects of these QTL are modest and additive, this study reveals that rapid size evolution can be genetically complex, even under natural conditions. Comparisons with laboratory-selected mouse strains suggest parallels between natural and artificial selection for body size, though distinct loci contribute to the trait in each context. This work advances our understanding of the genetic basis of extreme body size evolution in island ecosystems.

Gray, M. M., Parmenter, M. D., Hogan, C. A., Ford, I., Cuthbert, R. J., Ryan, P. G., Broman, K. W., & Payseur, B. A. (2015). Genetics of Rapid and Extreme Size Evolution in Island Mice. Genetics, 201(1), 213–228. https://doi.org/10.1534/genetics.115.177790