Friday, October 12, 2012: 9:20 PM
Hall 4E/F (WSCC)
Natural hybrid systems allow for the study of sexual and natural section as they may be responsible for populations that are free to evolve in novel directions. The hybrid system of Xiphophorus fish has been shown to be replicated in seven streams along an elevation gradient. The two parental species, Xiphophorus birchmanni and X. malinche, are found in different habitats, a factor that may explain the significant differences in morphology between the two species. To determine if these replicated hybrid zones have unique divergence, morphometric data of the parental species and hybrids was collected. Landmarks were digitized for the upper lip, the end of the caudal peduncle, the frontal tip of the dorsal fin, the pectoral fin, the latter tip of the dorsal fin, the end of the pectoral fin, the top and bottom edge of the tail, the end of the tail, and the tip of the sword on images of fish taken from multiple populations. Morphometric measurements were taken from the landmarks using R. This data was also used to elucidate the relationship between sexual and non-sexual traits and whether they diverge in alternate directions relative to each other. We expect hybrids to display greater morphological variation than parentals, in addition to greater among population variance relative to parentals. Given that the hybridization events occurred seven independent times, each hybrid zone is likely to have independent patterns of phenotypic variation.