Abstract: This experiment was to study the effect of the polymorphisms in the Leptin gene and SCD1 gene. By direct sequencing of PCR products, 7 SNPs were found in the Leptin gene exons 2 and 3, of which four were non-synonymous mutations; 1 SNP was found in the SCD1 gene exon 5, which was a non-synonymous mutation. Allelic substitution effect of all the SNPs on 25 single fatty acids, monounsaturated and polyunsaturated and desaturation indexes were tested. The results showed that both the SCD1 SNP and 3 SNPs of the Leptin gene affected the desaturation of FA into MUFA to different extents. It was reported that one of the roles of Leptin in the metabolism was to down regulate the transcription level of SCD1 gene, so, it possible that the non-synonymous mutations in the Leptin gene also contributed to the variability of FA composition in muscle fat except for the mere additive effect of SCD1 gene on FA desaturation.

Key words: Leptin gene; SCD1 gene; desaturation; fatty acid; SNP