The analysis of egg hatchability in crosses between F 2 hybrids showed no apparent association between the presence or absence of the W chromosome and the level of their fertility Figure 5a. Schematic illustrations of sex chromosome constitutions in both sexes of Samia cynthia pryeri and Samia cynthia walkeri.
The consequences of this gap are particularly acute for reptiles given that they exhibit the highest prevalence of TSD known so far. If TSD permits sex-ratio compensation for environmental variability, then it may be positively selected Girondot and Pieau
Abstract Reptiles sauropsids represent the sister group to mammals, and the basal members of Reptilia may provide a good model for the condition of the common ancestor of both groups. The sexual differentiation is generally triggered by a main gene a "sex locus"with a multitude of other genes following in a domino effect.
Cambridge: University of Cambridge.
As new genomic approaches increase the pace of discovery and characterization of sex determination innon-model organisms, we anticipate that comparative phylogenetic methods will be key to examining the roles of various ecological and genetic factors that drive changes in sex determination mechanisms.
However, the genomic revolution has allowed researchers to address scientific questions and tackle novel biological systems at the molecular level. Parnell NF, Streelman JT Genetic interactions controlling sex and color establish the potential for sexual conflict in Lake Malawi cichlid fishes.
Genomic DNAs were extracted separately from females and males by standard phenol—chloroform procedure. Recently Kiuchi et al. Conflicting selection on different parts of the genome and on the two sexes may drive many of these transitions, but few systems with rapid turnover of sex determination mechanisms have been rigorously studied.