Background Matters

See allHide authors and affiliations

Science  02 Oct 2009:
Vol. 326, Issue 5949, pp. 19
DOI: 10.1126/science.326_19c

Species boundaries are often maintained because of reinforcement—where the male offspring of individuals of two different species are sterile. Although several candidate genes contributing to this reproductive barrier have been identified, the mechanisms by which sterility is conferred are still generally unknown. The dominance theory suggests that sterility is caused by interactions of X-linked loci from one species with dominant autosomal loci in the other species. Chang and Noor have investigated this phenomenon by introgressing putative sterility quantitative trait loci (QTLs) from one fruit fly species into another, individually and in combination. They found that no single allele of any of the QTLs resulted in hybrid sterility but that sterility increased in the presence of other QTLs, even when all genes were heterozygous. These data suggest that the genetic background is responsible for modifying the degree of dominance and demonstrate that epistasis is an important component of hybrid male sterility.

Evolution 63, 10.1111/j.1558-5646.2009.00823.x (2009).

Navigate This Article