Pakistan is blessed with rich sheep genetic resources being a source of milk, meat and wool across the country. There has been a very limited work on sheep genetic exploration. The Leptin a 16-kDa protein has been involved milk yield, energy balance, feed intake regulation, fertility and immune functions in animals. This gene is getting importance for animal researches to find useful biomarker for identification of high performing animals with better adaptability and productivity. In the present study, the polymorphism of the leptin gene in Lohi, Kajli and Sipli famous sheep breeds of Pakistan was analyzed by PCR-RFLP technique using six restriction enzymes (BbvI, SfcI, AccI, Sty1, BsmF1, Ban II) that showed monomorphic pattern in intron 2 (position A2262T, C2256G, -2730C) and exon 2 (A3201G) while polymorphic trend was observed in intron 2 (at position C1467T and A3050-). BbvI was found monomorphic Lohi and Sipli sheep while polymorphic in Kajli sheep at position C1467T. Interestingly the Sty1 enzymes was proved polymorphic (A/-) at position 3050 in Lohi, Kajli and Sipli sheep breeds of Pakistan. The SfcI, AccI, BsmF1 and Ban II enzymes showed monomorphic results in all breeds. The different production traits can be associated with leptin genotypes in future and we recommend that polymorphisms in Leptin gene may be used to develop useful markers for selection of better animals under Maskers Assisted Selection program.

Key words: Leptin gene, Pakistan, Polymorphism, PRC-RFPL, Sheep breeds