Genetics of stable polymorphisms

The Anolis genus of lizards are one of the most speciose group of vertebrates.  Distributed throughout the new world tropics this diverse group of lizards are easiy identifiable through the incredible variety of colours and patterns, particularly in their dewlaps (an extensible flap of skin on their throat).  In most cases the dewlap varies in colour and/or pattern between species, but in a few species there is also a colour/patttern polymorphism between populations of the same species.

One such species, Anolis apletophallus, occurs in central Panama in the rainforest surrounding the Panama canal.  Populations on the eastern side of the canal have a white dewlap with an orange spot, while populations to the west of the canal have an almost entirely orange dewlap.  In some populations both morphs occur together, and this project investigates the genetic basis of the colour polymorphism and the role of different forms of selection on its maintenance.

The project is led by Jessica Stapley, and much more detail about the project can be found on her webpage.  Jess has done a mountain of work in captive breeding and mate choice experimentation and has begun to disentangle what is going on.  My role in the project is to perform the bioinformatics.  As part of a consortium, Jess has sequenced the genome of A. apletophallus, and we have also generated RADtags (Restriction site associated DNA – the DNA gets fragmented at particular sequence sites across the genome) from wild animals from several populations as well as offspring from controlled laboratory crosses.  We are using this data to identify SNPs (Single Nucleotide Polymophism – genetic differences) and perform several tests (e.g. Genome Wide Association Scan – GWAS, identify outlier loci) to identify which regions of the genome are associated with differences in dewlap pattern and to construct a genetic linkage map.