Until recently, it was commonly held that the morphologic differences between male and female brains arise due to secretion of sex-specific gonadal hormones during fetal development. However, recent studies have shown that there are sex differences in genetic expression before the development of sex gonads. In mammals, sex is determined at conception by a set of sex-specific genes. Expression of these sex-specific genes influences the developing brain by regulating the neuroanatomy and its function.

Sex-determining Region Y (SRY) is a gene located on the Y chromosome that specifies and directs male development. SRY expression is found in a specific subset of tyrosine hydroxylase-expressing neurons in the substantia nigra of males. Tyrosine hydroxylase affects synthesis of dopamine, a stimulatory neurotransmitter that influences motor function. In studies conducted on male rats, knock down of SRY resulted in dopamine deficiency causing abnormal motor function. Reversal of the knock down led to normal SRY levels with, resumption of normal dopamine production and motor function (1).

Log in or create a free account to read this content

Gain free access to this article, as well as selected content from this journal and more on nature.com

Access through your institution

or

Sign in or create an account
Continue with Google
Continue with ORCiD