Problem:
We have previously examined how sex chromosomes influence sex differences by determining gonadal development and synthesis of steroid hormones such as testosterone and estrogen. We also touched upon the fact that in mammalian cells, the XY or XX chromosomal complement alone can drive sex-specific cellular physiology. This process applies to the brain as well. For example, a group of researchers found that in male rats, Sry is highly expressed in brain areas with an abundance of dopamine-producing neurons, such as the substantia nigra and the ventral tegmental area. As you may recall, SRY is the protein encoded by the Y chromosome-linked Sry gene, which was primarily known as the key orchestrator of male sexual determination by acting within the gonadal tissue, so this finding was quite surprising. Interestingly, the researchers further discovered that inhibiting SRY expression-by directly injecting compounds that prevent the synthesis of the SRY protein-led to a decrease in tyrosine hydroxylase levels, an enzyme critical for the production of dopamine. Dopamine is crucial for motor movement, so this inhibition also resulted in motor deficits (Dewing et al. 2006). These results suggest that the production of dopamine in certain neurons is distinctly regulated in males versus females simply by the presence of the Y chromosome in males, without any mediation by gonadal hormones. Remarkably, this group recently discovered that overexpression of SRY in dopamine neurons may explain. Need Assignment Help?