Genetic sex identification in orangutans.

To date, no established protocol for genetic sex identification in orangutans (Pongo pygmaeus) exists. In nearly all apes (gibbons, gorillas, chimpanzees, and humans), genetic sex identification is possible using the amelogenin gene because copies located on X and Y chromosomes have different sizes. Here we report that orangutan sex identification can be resolved through multiplex polymerase chain reaction (PCR) of the Y-linked SRY locus and the amelogenin locus. PCR amplifications of orangutan amelogenin produces one fragment size in both sexes, while SRY amplifies only in males. This protocol will allow primatologists to identify the sex of orangutans through genetic analysis.