There is another interpretation of the mitochondrial DNA data presented in this article. The data make it clear that the more advanced Cro-Magnon males only mated with Cro-Magnon females; however, there is no evidence that the Cro-Magnon females didn’t mate with the more muscular Neandertal males.

Jeff Nicoll and Joan Cartier
Washington, D.C.

Much mixing between Neandertals and Homo sapiens could have occurred without leaving any evidence in mitochondrial DNA, which is inherited only from mother to daughter. This would happen if the women stayed with the groups they were born in while the men wandered about and interbred.

Bruce R. Mehlman
Richmond, Calif.