COLLABORATIVE RESEARCH: Evolution of Sex Chromosomes in Turtles

Harvard University, Cambridge MA

Investigators

Abstract

Sex is determined by genetic constitution (GSD) in most animals, such as by the sex chromosome pairs XX or XY in humans, or ZZ or ZW in birds. In certain other animals, however, sex is determined by environmental temperature (TSD). Among turtle species, however, examples of both types of sex determination can be found. It remains unclear, however, how and why different sex determining mechanisms exist. This collaborative project will help fill this gap by comparing the chromosomes and sex-related genes of turtles using XX/XY, ZZ/ZW, or TSD mechanisms for sex determination. Particularly, this research will test whether (1) all sex chromosomes in turtles derive from a common ancestral pair of non-sex chromosomes (or "autosomes"), and whether (2) the molecular evolution of genes located on turtle sex chromosomes differs from that of the same genes in TSD turtles, in which there are no sex chromosomes- i.e., whether the sequences of genes located on sex chromosomes change differently over evolutionary time than do the sequences of the same genes when they are located on autosomes. This project will integrate undergraduate discovery-based learning for undergraduates into the field and lab modules of this project and will broaden the participation of underrepresented groups in biology by providing direct training opportunities for students and their mentors, by engaging women and minorities through outreach activities, and by providing further opportunities for both the investigators to serve as role models for minorities.