Genome-wide patterns of ancestry in semi-natural hybrid populations of the fish Xiphophorus malinche x Xiphophorus birchmanni (family: Poeciliidae) across an elevational gradient

Hybridization is a widespread natural phenomenon, yet many aspects of it remain poorly understood. Climate change and anthropogenic activities are increasing species displacement and altering reproductive barriers, potentially increasing the frequency of hybridization events. Especially in current times, species are required to quickly adapt to changes, and hybridization, despite having some clear disadvantages, has been shown to be a common way for species to acquire adaptive traits from neighbouring species. Understanding the adaptive potential of hybrids will therefore be relevant for both evolutionary and conservation studies. This thesis explores how semi-natural populations of Xiphophorus birchmanni x Xiphophorus malinche hybrids living at different elevations are adapting to their environment using ancestry informative markers from whole-genome sequencing.