Determination of gender in cetaceans by the polymerase chain reaction

Abstract

We determined the gender of a variety of cet can species, including both ondotocetes and mysticetes, using the polymerase chain reaction for amplification of the sex chromosome specific regions ZFY/ZFX and SRY. This quick and simple method requires extremely small amounts of tissue, and therefore allows gender to be determined from skin biopsies taken from free-ranging specimens. In the fin whale, Balaenoptera physalus, no gender-specific bands were observed when the ZFY/ZFX system was used, but when the SRY system was used, sex was accurately determined. Previous studies in other mammals have also shown the SRY system to be more reliable in sex determination. We therefore recommend amplification of the SRY region alone or in parallel with the ZFY/ZFX regions, as described here, as a test for gender in cetaceans and other mammals.