LTREB: Social, Environmental, and Evolutionary Dynamics of Replicated Hybrid Zones in Swordtails (Teleostei: Xiphophorus) of Mexico's Sierra Madre Oriental Grant uri icon


  • The study of natural hybridization - the exchange of genetic information between species - is fundamental to further understanding how genes function within organisms and within the environment. Hybrids - crosses between different species - can also be used to identify specific genes associated with traits of interest and how these genes interact with environmental variation, ultimately shedding light on the genetic basis of disease and adaptation to environmental change. This project studies changes in behavioral decisions, communication signals, heat and cold tolerance, and population structure over 10 years in natural and experimental populations of swordtail fish, a longstanding model in genetics, physiology, and behavior. The two parent species are found at high and low elevations, hybrids at intermediate elevations. Experimental populations will seed first-generation hybrids along an elevation gradient. The predicted response at the high elevation site is that genes associated with cold tolerance will spread along with the communication signals and behavioral biases of the high-elevation species, and vice-versa at the low elevation site. The study will identify novel genes involved with decision-making, communication, and temperature tolerance, which may lead to applications in medicine and agriculture. Further, the data will address the extent to which specific, identifiable parts of the genome are responsible for adaptation to various environments. Collection and analysis of data will be accomplished with a structured summer mentorship program between undergraduate students and local K-12 students. Because of the long-term nature of the study, K-12 trainees will have the opportunity to become mentors themselves later in the project.

date/time interval

  • 2014 - 2020