Experimental animal models are extremely valuable for the study of human diseases, especially those with underlying genetic components. The exploitation of various animal models, from fruitflies to mice, has led to major advances in our understanding of the etiologies of many diseases, including cancer. Cutaneous malignant melanoma is a form of cancer for which both environmental insult (i.e., ...

The X and Y chromosomes of the platyfish (Xiphophorus maculatus) contain a region that encodes several important traits, including the determination of sex, pigment pattern formation, and predisposition to develop malignant melanoma. Several sex-chromosomal crossovers were identified in this region. As the melanoma-inducing oncogene Xmrk is the only molecularly identified constituent, its genom...

ent sword as a control. Because swordlessness is the ancestral state of the Xiphophorus clade, Basolo argues that the results of her experiment indicate that female preference for swords predates the evolution of the sword and concludes that coevolutionary models of sexual selection are inadequate. Basolo provides no direct evidence in support of a preexisting female sensory bias, but rejects t...