Comparison of goat, sheep, cattle and water buffalo leptin (LEP) genes and effects of the Intron 1 microsatellite polymorphism in goats

We report and compare the partial genomic sequence (from part of Intron 1 to part of Exon 3) of goat, sheep, cattle and water buffalo leptin (LEP) genes. Genomic DNA was obtained from leukocytes of 117 goats belonging to six breeds (Angora, Alpine, Garganica, Girgentana, Maltese and Red Syrian); 30 sheep belonging to five breeds (Altamura, Sarda, Apulian Merino, Leccese, Apennine) 50 water buffaloes and 43 Italian Friesian cattle. All the four species had a microsatellite region in Intron 1. According to the results of a population analysis, we observed 10, 5, and 2 alleles, in cattle, water buffalo and goats, respectively, in this region. No nucleotide variation was observed in sheep. The results of this study show that in Red Syrian goats the two alleles are associated with significantly different effects on beta-hydroxybutyric acid (P = 0.04) and free thyroxine (P = 0.018) levels, and milk somatic cell counts (P = 0.034). The same microsatellite region was tendentially associated with variation in insulin-like growth factor-1 (P = 0.082) and triglycerides (P = 0.072) levels. The results of this study are further evidence for the role of leptin as an indicator of metabolism and mammary gland health in dairy ruminants.