Meeting Abstract

S1-1.4  Thursday, Jan. 3  Comparative expression and genomic organization of sex-differentiating genes in a bird and a reptile JANES, D.E.*; EDWARDS, S.V.; Harvard University; Harvard University djanes@oeb.harvard.edu

Although sex-determining mechanism differs between birds and some reptiles, several genes associated with sex differentiation are found in both groups. For example, American Alligators do not have heteromorphic sex chromosomes. They exhibit temperature-dependent sex determination (TSD). In contrast, Emus have minimally differentiated sex chromosomes. Like all birds, they are genotypically sex-determined (GSD). We fluorescently labeled bacterial artificial chromosomes to map avian sex-linked and sex-related genes in both species. We also analyzed cDNA from embryonic and adult tissues in both species to compare expression of sex-related genes among different stages, tissues and species. By comparing expression and chromosomal location of sex-related genes common to both species, we aim to describe similarities between TSD and GSD and the evolution of characteristically ancient avian sex chromosomes as seen in Emus from ancestral reptilian autosomes as represented in Alligators.