A PCR-based Method for Sex Identification in Hippopotamus amphibius

Document Type


Publication Date




Publication Title

African Zoology


hippopotamus, sex identification, zoology, polymerase chain reaction, HaeIII, field sexing, zinc finger protein, PCR, ZFX, ZFY, Hippopotamidae

Subject Categories

Biology, Zoology, Sexing--Hippopotamus, Hippopotamus amphibius


Presents a study that developed a polymerase chain reaction-based method for the identification of the sex of the Hippopotamus amphibius.

Identification of the sex of aquatic mammals such as the hippopotamus (Hippopotamus amphibius) is difficult in the field. We have developed a PCR-based method for sex identification in the hippopotamus. This method amplifies a short fragment of the ZFX [zinc finger protein, X-linked] and ZFY [zinc finger protein, Y-linked] genes from the X and Y chromosomes. The PCR products are then digested with the restriction endonuclease HaeIII. The method was verified using tissue samples taken from six captive animals in zoos. We then collected 54 tissue samples from free-ranging hippos in Kruger National Park, South Africa, using a biopsy dart and cross-bow. The PCR method correctly identified the sex of all individuals for whom the sex was known (either zoo animals, or those exhibiting clear behaviours or morphologies in the field). Field identification of the sex of other individuals was prone to error (6 of 22 misidentified, 27 %).