Dr. Luis Martín San José García

Evolutionary origin and maintenance of colour polymorphisms and associated alternative life-history strategies

Selection leads to evolution by filtering the extant population phenotypic variability and fixing the most successful solution to the problem of survival and reproduction. However, more than one single solution often exists to that problem and organisms can adopt different strategies that can finally coexist within the same population. Colour polymorphisms (i.e., genetically-based discrete variation in colour) often reflect such strategies either because colour is required to signal the strategy to conspecifics or because colour is at the very core of the strategy itself (e.g., alternative strategies for camouflage). Therefore, colour polymorphisms offer a unique opportunity for biologists to easily monitor within-population variation and to investigate what selective forces allow several life-history strategies to coexist and, in general, how diversity can be maintained.

My own research focuses on two main questions revolving around colour polymorphism. On one hand, I am interested in what kind of selective forces (disruptive selection, frequency-dependent selection,…) act on colour morphs and associated life-history strategies while, on the other hand, I am interested in the genetic architecture that assures a stable association between colour polymorphism and life-history strategies in the face of gene flow. Currently, I am investigating these questions in the barn owl, Tyto alba, combining different approaches. On one hand, I am using correlative and experimental approaches to test whether prey-predator relationships, and more particularly, whether prey visual system drive the evolution of colour polymorphism in this species. On the other hand, I am investigating the genetic basis of colour variation and colour-related traits using approaches such as animal models, candidate genes, and genome-wide association studies.