The Little Difference that Made Sauria Roam the Sea

摘要

Whereas sex chromosomes are a way to determine the sex of an organism genotypically, the sex of certain reptiles can instead be determined by exposing the developing embryo to a higher or lower temperature. A recent paper by Organ et al. (2009) suggests an interesting correlation between genotypic sex determination, live birth (viviparity), and the adaptive radiation of species. By looking at the sex-determining mechanism and the mode of reproduction in 94 amniote species, such as mammals, birds, and reptiles, the authors developed an algorithm that let them accurately predict the correlation between the mechanism of sex determination and mode of reproduction.