The evolution of sex ratios and sex-determining systems.
Sex determination is a fundamental process governed by diverse mechanisms. Sex ratio selection is commonly implicated in the evolution of sex-determining systems, although formal models are rare. Here, we argue that, although sex ratio selection can induce shifts in sex determination, genomic conflicts between parents and offspring can explain why single-factor systems (e.g. XY/XX or ZW/ZZ) are common even in species that experience selection for biased sex ratios. Importantly, evolutionary shifts in sex determination do not always result in the biased production of sons and daughters sensu sex ratio theory. Thus, equal sex ratios might be an emergent character of sex-determining systems even when biased sex ratios are favored by selection.
Uller
Tobias
T
School of Biological Sciences, University of Wollongong, Wollongong, NSW 2522, Australia.
Pen
Ido
I
Wapstra
Erik
E
Beukeboom
Leo W
LW
Komdeur
Jan
J
D000818:Animals; D005075:Biological Evolution; D017753:Ecosystem; D005838:Genotype; D008954:Models, Biological; D012641:Selection, Genetic; D019849:Sex Determination Processes; D012744:Sex Ratio