Ana-Marija Sulic: Sex determination in some cetacean species by amplification of a part of the sty gene. Diploma Thesis. Faculty of Science. Zagreb, 2004.




Investigations of cetacean biology often encounter problems in obtaining information. Determining the gender of living cetaceans is very difficult since in most species sexually-dimorphic characters are poorly marked. Sometimes it is not even possible to morphologically determine sex of a dead animal due to its advanced state of decomposition. The purpose of this study was to introduce a reliable, fast and simple method for molecular sexing of cetaceans that could be used on tissue samples from carcasses, as well as on skin biopsies from living animals. Total DNA was extracted from tissues of 48 cetacean carcasses; 29 bottlenose dolphins (Tursiops truncates), 9 striped dolphins (Stenella coeruleoalba), 6 Risso's dolphins (Grampus griseus), 2 Cuvier's beaked whales (Ziphius caxirosths) and 2 fin whales {Balaenoptera physalus). One sample was a skin biopsie from a living bottlenose dolphin. The introduced method uses polymerase chain reaction (PCR) and four oligonucleotide primers to simultaneously amplify a part of the sry gene located on the Y chromosome and regions of ZFX/ZFY, gene located on Y and X chromosomes, respectively. Amplification products differed in length and therefore gave distinct, sex-specific bands on 1% agarose gel after electrophoresis. The sex of 37 cetacean specimens was successfully determined. Method was shown to be reliable and efficient when applied on fresh or relatively well preserved samples, but failed incases of strongly decomposed tissues.