Meeting Abstract
P1.153 Friday, Jan. 4 Characterization of the Poecilia mexicana transcriptome: a model for adaptation and speciation research PASSOW, C.N.**; KELLEY, J.L.; TOBLER, M.; Oklahoma State University ; Stanford University; Oklahoma State University Courtney.passow@okstate.edu
Adaptation and speciation are key processes in evolution and elucidating the genomic basis of traits involved in these processes remains a major task for the field. Poecilia mexicana (Poeciliidae) is a livebearing fish that lives in normal streams as well as in toxic, hydrogen sulfide springs throughout southern Mexico. Sulfide springs were colonized by evolutionarily independent lineages that exhibit strong patterns of convergent, adaptive trait divergence and are reproductively isolated from adjacent stream populations. Due to the recent divergence of ecotypes inhabiting different habitats, this system is ideal to study the potential underlying genetic basis of adaptation and speciation. Identifying genetic changes involved in adaptive trait divergence involves quantifying coding changes in the genome and changes in gene regulation. We used RNA-sequencing on an Illumina HiSeq platform to assemble and annotate a reference transcriptome for P. mexicana based on transcripts from 36 wild-caught females. The assembled transcriptome showed high congruence with other published fish transcriptomes, such as medaka, zebrafish, and stickleback. Using BLAST, we focused on identifying candidate genes that are potentially under positive selection between populations from non-sulfidic and sulfidic populations, and identified genes involved in general and oxidative stress responses, as well as in sulfide metabolism and hypoxia tolerance. We validated several candidate gene sequences with RT-PCR and sequencing. The P. mexicana transcriptome provides a valuable genomic resource for studying the underlying genetics of adaption and speciation, and contributes to the growing number of genomic resources in the family Poeciliidae, which is used in a wide range of behavioral, ecological, evolutionary, and medical genetic studies.
