Mate choice, genetic variation, and population structure in hybrid zones
My current research is focused around population genetics in swordtail hybrid zones that are located on the slopes of the Sierra Madre Oriental of Hidalgo, Mexico (CICHAZ Link). I’m interested in the evolutionary genetics of mate choice and sexual selection, ecological genetics and phylogeography more broadly. At present, I’m studying population genetic patterns of live bearing fish in replicated hybrid zones (see Culumber et al. 2010). Natural hybridization provides a means to study evolutionary phenomena such as the mechanisms of reproductive isolation, but can also provide a window on larger environmental problems.
The hybrid zones between the species with which I currently work are thought to have formed due to interruption of olfactory communication due to anthropogenic disturbance. In other words, people directly and indirectly contaminate the water such that the fish can no longer smell their own species from the other and “accidentally” mate with the wrong species. The people rely on the rivers as a source of water, to flush away waste water (which is often not treated), and to bathe and wash dishes and clothes. Other times, poor infrastructure results in damaged drains and waste water systems which allows dirty drain water to seep directly into the rivers (see photos below).
Above I said “accidentally” mate with the wrong species, because research shows that females of one species have greater fidelity to males of their own species than do females of the other species. Xiphophorus malinche females are less choosy and, as you can see in this CSI:Calnali special, this can have important consequences.
Ultimately, the goal of my research is two-fold: 1) to better understand what mechanisms contribute to variation in population structure in the hybrid zone and 2) to have data that can be used and combined with other sources of data to help local policy makers form decisions regarding water management. Clean water is not only essential to wildlife but for the people themselves. Population genetic data clearly show that hybridization, and potentially contamination of water, is widespread. Together with upcoming water quality data, we should have a solid foundation of data that can be used for local water policy decisions.
The ABS program has been important for helping forge connections and collaborations with scientists in other fields and to broaden my own expertise by exposing me to areas I would otherwise not experience in a traditional PhD in biology through ABS classes and seminars. As stated above, through collaborations both at TAMU and a university in Mexico, I hope to better understand how water quality affects swordtail genetics and how these data, in turn, relate to municipal water policy and local perspectives on the state of water quality. The goal being that this may help local governments make more informed decisions that can help both wildlife and human populations that rely on clean water.
Click here to see more pictures of my field work.