Example of a swordtail field site - San Luis Potosí, MX
Evolution of small body size in Xiphophorus
How does evolution orchestrate the repeated emergence or loss of sexually selected phenotypes? Swordtails (genus Xiphophorus) exhibit a vast amount of morphological diversity, including pigmentation patterns, sexually selected ornaments, and body size. Within the Northern swordtail clade, there are several species with dramatically smaller body sizes than the others. Using new whole-genome sequence data, I constructed an updated phylogeny for Xiphophorus and investigated the evolutionary history of sexually selected traits that coevolve with body size across the genus. The results of this work were published in Evolution.
Skills: phylogenomics | phylogenetic comparative methods | global ancestry inference | sequence alignment | variant calling | R | bash
Genomic architecture of a body size polymorphism
Several swordtail species exhibit stable polymorphisms in male body size, where males are either large and develop sexual ornamentation to attract mates or small and lack sexual ornamentation to engage in coercive mating tactics. Candidate gene studies have shown that much of the variation underlying this polymorphism is attributed to copy number variation of the melanocortin-4 receptor gene on the Y-chromosome, but to fully characterize the variation, a whole-genome approach is required. Therefore, I generated PacBio genome assemblies for each male morph and am currently using GWAS and RNA-seq to to explore the genomic architecture and functional drivers underlying this polymorphism.
Skills: GWAS | PLINK | RNA-seq | differential expression analysis | PacBio genome assembly | Python | R | bash
Undergraduate research
Prior to graduate school, I studied the neural gene expression patterns of mouthbrooding (an extreme form of parental care behavior) in African cichlids. I also evaluated methods for detecting inter-species copy number differences.
Skills: qRT-PCR | RNA-seq | differential expression analysis | cryosectioning | histology | Python | R | bash | sequence alignment | protein-protein interaction networks