Molecular and bioinformatics analysis of regulatory upstream region of leptin and SIGLEC5 genes in association with production and reproduction traits in Holstein cattle

The aim of this study was the molecular and bioinformatics analysis of regulatory upstream region of leptin and SIGLEC5 genes in association with production and reproduction traits in Holstein cattle. For this purpose, 300 blood samples were collected randomly and DNA was extracted. Two fragments of 251 and 406 bp from regulatory upstream regions of leptin and SIGLEC5 genes were amplified by PCR and genotyping was done by SSCP method. One sample from each banding pattern was sequenced and bioinformatics analysis were done by BioEdit and DNASIS MAX softwares. The SIGLEC5 locus was monomorphic, whereas, four banding patterns of A, B, C and D with frequencies of 0.25, 0.36, 0.22 and 0.17 were observed in leptin locus, respectively. Statistical analysis showed that leptin gene polymorphism was significantly (P<0.05) associated with milk lipid and status of parturition, so that cows with banding pattern A had the highest milk fat and cows with banding pattern D showed lowest milk fat. Also, cows with banding pattern D had the best status of parturition (easy birth) (P<0.05). The bioinformatics analysis showed 14 and nine motifs in SIGLEC5 and leptin genes, respectively. Therefore, according to the results of this study, leptin gene can be suggested to improve production and reproduction traits. In addition, complementary studies on other regions of SIGLEC5 gene to find relations between production and reproduction traits in Holstein cattle are highly recommended.