Sex differentiation begins with differential expression of Sry and then Sox9 in the genital ridges at E10.5.
The majority of chelonians don't rely on chromosomes for sex differentiation but on incubating temperature.
A new book, Brainstorm, by Rebecca Jordan-Young exhaustively analyses every relevant study on hormonal sex differentiation of the human brain, and argues that they are riddled with weaknesses, inconsistencies and ambiguity.
Objective: To analyze male and female sex differentiation in monozygotic twins.
Sex differentiation begins in the embryo under genetic and hormonal control.
Both genes were expressed in gonads, and their expression level increased before gonadal sex differentiation.
SF-1 is involved in gonadal and adrenal development, sex differentiation and steroidogenesis.
Overall, these results suggest that these two genes play a key role in the sex differentiation of willow minnow.
This study was designed as an attempt to understand the sex differentiation mechanism of willow minnow at the molecular level.
Differently, in Holstein cattle, the piebald effect seems to be due to inheritance of a single piebald spotting gene, with no sex differentiation (Pape 1990), unlike in camels.
The unique plasticity of sex differentiation in fish suggests that these animals may be very susceptible to disruption of sexual characteristics by pollutants.
