PCR-based sex determination of cetaceans and dugong from the Indian seas

Abstract

A sex-determination technique based on PCR amplifi- cation of genomic DNA extracted from the skin tissue has been standardized in cetaceans and dugong sam-pled from the Indian seas. A Y-chromosome-specific region (SRY or Sex-determining Y-chromosome gene) of 210–224 bp size in the genome has been amplified (only in males) using specific PCR primers. A fragment of the ZFX/ZFY (zinc finger protein genes located both on the X and Y chromosomes respectively) re-gion in the size range 442–445 bp is also amplified (in both sexes) using another pair of primers simultaneously as positive controls for confirmation of sex. Molecular sexing was standardized in spinner dolphin (Stenella longirostris), bridled dolphin (Stenella attenuata), bottlenose dolphin (Tursiops aduncus), Indo-Pacific humpbacked dolphin (Sousa chinensis), Risso’s dolphin (Grampus griseus), finless porpoise (Neopho-caena phocaenoides), sperm whale (Physeter macro-cephalus), blue whale (Balaenoptera musculus), Bryde’s whale (Balaenoptera edeni) and dugong (Dugong du-gon), which are all vulnerable/endangered species pro- tected under the Indian Wildlife Act.