Abstract
Leptin hormone plays an important role in many biological processes in animals and humans such as appetite, immune system and reproduction. We evaluated the genetic variability in the leptin (LEP) exon 3 gene in Saudi indigenous Najdi (n=41) and Naeimi (n=40) sheep. A 1041-1058 bp fragment was amplified, sequenced and three non-synonymous single nucleotide polymorphisms (two transition and one-transversion) were found at positions 170, 286 and 332 of the exon 3 coding region. In addition, two insertion-deletion (indel) mutations were detected in the 3' UTR of LEP exon 3; the first indel was 16 nucleotides in length and the second indel was only a single nucleotide. Four out of the five detected mutations have been found in other international sheep breeds. The most frequent LEP genotypes (01 and 02) in Najdi and Naeimi sheep were also found to be the most common genotypes in GenBank database. However, the data revealed that the single base indel in the 3' UTR was unique to the Najdi breed. On the other hand, 42% of the total studied individuals were heterozygous at LEP locus.