Association analyses of single nucleotide polymorphisms in the leptin and leptin receptor genes on milk and morphological traits in Holstein cows

To date, only a few SNP in the leptin receptor gene have been detected and analyzed while the leptin gene has been extensively characterized and several polymorphisms were detected and associated to functional and productive traits in cattle. In this work, for the first time, the bovine leptin receptor gene was fully characterized by sequencing the whole coding region and part of the 5’ flanking region. A group of 95 Holstein cows was genotyped in order to search for SNP at both the LEPR and LEP genes, and to associate them with milk and morphological traits. Nine novel SNP in the leptin receptor gene and one novel SNP in the leptin gene were detected. Four SNP of the leptin receptor gene and one SNP of leptin gene showed a significant effect on one or more analyzed traits, and, in all cases, the greatest effect was observed on fat content. This study provided knowledge of the existence of further polymorphisms in the leptin receptor and leptin genes that have an influence on some important economic traits.