Proper control of genetic background with precise allele substitution: a comment on Coyne and Elwyn.

Coyne and Elwyn report that, using Drosophila stocks provided by us, they were unable to replicate our experiments measuring the effects of desaturase-2 on stress tolerance. In this note, we provide evidence that these authors did not properly control for the differences in genetic background between the lines. Their experiments are thus not meaningful replications of our previous ones. We discuss ways of circumventing this problem in studies involving induced mutations in single genes.