SRY and Hypertension: Rat SRY is significantly different to that of humans not only in terms of copy number but also in terms of the gross protein structure: human SRY lacks a polyglutamine (Q-)-rich motif present in rat SRY and the high-mobility group (HMG)-box region important for DNA binding is in a different location.28 Nevertheless, human SRY has been shown to influence expression of rat and human RAAS genes in vitro,33 suggesting potential to play a role in genetically acquired human hypertension.