Having a second pair of hands might seem like an advantage but animals born with extra limbs, because of changes in their DNA, generally do not fair well. For more than 25 years, scientists have known about the existence of a mutation in a fruit fly gene that causes just such aberrant appendages, yet the [...]
Nearly 60 years ago, Pamela Lewis, a geneticist at the California Institute of Technology in Pasadena, noticed that some of the flies she was experimenting on had tiny comb-like structures on their second and third pairs of legs, and not
just the first pair as is usual.
Lewis called these structures ‘sex-combs‘ because males use them [...]