Olsson Lab

Research Focus

Sex Allocation and Sex Determination

 

Reptiles have a diversity of modes for sex determination. Some reptile species have a strong genetic basis for sex determination (GSD) with either heteromorphic sex chromosomes (XX/XY and ZZ/ZW systems) or micro-sex chromosomes.

In other species, the environmental conditions that the embryo experiences in the egg during development determine the sex (e.g. temperature-dependent sex determination: TSD). This diversity of sex determining modes begs for studies to determine the selective forces that could be driving these systems.

 

 

Furthermore, in species that have TSD the mother may have more control over the sex of her offspring by carefully choosing a particular site to make her nest. In this way, she may be able to adjust the sex ratio of her clutch to favour the sex that would benefit the most from that particular environment or her (or the father’s) genes.