Shahid Bahonar University of Kerman and Iranian Biotechnology Society Agricultural Biotechnology Journal 2228-6705 17 4 2025 10 23 Association of Single Nucleotide Polymorphisms in Exon Two of the Leptin Gene with Growth Traits in Lori-Bakhtiari and Zel Sheep Association of Single Nucleotide Polymorphisms in Exon Two of the Leptin Gene with Growth Traits in Lori-Bakhtiari and Zel Sheep 27 50 5053 10.22103/jab.2025.24374.1630 FA Parviz Azizi Department of Animal Science, Faculty of Agriculture, University of Tehran, Karaj, Iran. 0009-0005-0883-3677 Hossein Moradi Shahrbabak Department of Animal Science, Faculty of Agriculture, University of Tehran, Karaj, Iran. 0000-0002-6680-7662 Mohammad Moradi Shahrbabak Department of Animal Science, Faculty of Agriculture, University of Tehran, Karaj, Iran. 0000-0002-5255-609X Sara Nezhadi Department of Animal Science, Faculty of Agriculture, University of Tehran, Karaj, Iran. 0009-0006-5988-1617 Journal Article 2024 11 18 Objective Leptin is a product of the obesity gene expression and is mainly produced in adipose tissue. It is also associated with feed intake, growth, and lipid metabolism. The aim of this study was to investigate the polymorphism of the 271 base pair locus, including the entire exon 2 and part of intron 2 of the leptin gene in two sheep breeds, Lori-Bakhtiari and Zel, and to determine the relationship of this locus with growth traits and identify desirable genotypes for these traits in the studied sheep. Materials and methods In this study, blood samples were collected from 373 sheep, including 169 Lori-Bakhtiari lambs from the Sholi Breeding Station in Shahrekord, 74 Lori-Bakhtiari lambs from the industrial slaughterhouse of Farsan County, and 130 Zel sheep from the Shirang Breeding Station in Gorgan County. DNA extraction was performed using an optimized salting-out method. A 271-base pair (bp) fragment encompassing exon 2 and a portion of intron 2 of the leptin gene was amplified via polymerase chain reaction (PCR). Results Analysis of the 271-bp fragment (covering exon 2 and part of intron 2 of the leptin gene) using single-strand conformation polymorphism (SSCP) revealed nine distinct banding patterns. Sequencing of these patterns identified three mutations in this region. The first mutation (A/G 1416) has been previously reported in Iranian sheep breeds. The second mutation, located in the coding region, involves the insertion of a cytosine base (+C 1328), resulting in a truncated protein. The third mutation was found in intron 2, where a thymine-to-guanine substitution occurred at nucleotide 1566 (T/C 1566). The allele frequencies for the first mutation (+C 1328) were 0.552 and 0.935 in Lori-Bakhtiari and Zel sheep, respectively; for the second mutation (A/G 1416), 0.359 and 0.039; and for the third mutation (T/C 1566), 0.179 and 0.065. Comparison of the obtained sequences with those in the NCBI database identified six distinct genotypes. Conclusions Evaluations conducted in this study indicate a significant relationship between the identified genotypes in Lori-Bakhtiari sheep and traits such as birth weight, daily weight gain, cholesterol (p<0.05), and rump width (p<0.01). Objective Leptin is a product of the obesity gene expression and is mainly produced in adipose tissue. It is also associated with feed intake, growth, and lipid metabolism. The aim of this study was to investigate the polymorphism of the 271 base pair locus, including the entire exon 2 and part of intron 2 of the leptin gene in two sheep breeds, Lori-Bakhtiari and Zel, and to determine the relationship of this locus with growth traits and identify desirable genotypes for these traits in the studied sheep. Materials and methods In this study, blood samples were collected from 373 sheep, including 169 Lori-Bakhtiari lambs from the Sholi Breeding Station in Shahrekord, 74 Lori-Bakhtiari lambs from the industrial slaughterhouse of Farsan County, and 130 Zel sheep from the Shirang Breeding Station in Gorgan County. DNA extraction was performed using an optimized salting-out method. A 271-base pair (bp) fragment encompassing exon 2 and a portion of intron 2 of the leptin gene was amplified via polymerase chain reaction (PCR). Results Analysis of the 271-bp fragment (covering exon 2 and part of intron 2 of the leptin gene) using single-strand conformation polymorphism (SSCP) revealed nine distinct banding patterns. Sequencing of these patterns identified three mutations in this region. The first mutation (A/G 1416) has been previously reported in Iranian sheep breeds. The second mutation, located in the coding region, involves the insertion of a cytosine base (+C 1328), resulting in a truncated protein. The third mutation was found in intron 2, where a thymine-to-guanine substitution occurred at nucleotide 1566 (T/C 1566). The allele frequencies for the first mutation (+C 1328) were 0.552 and 0.935 in Lori-Bakhtiari and Zel sheep, respectively; for the second mutation (A/G 1416), 0.359 and 0.039; and for the third mutation (T/C 1566), 0.179 and 0.065. Comparison of the obtained sequences with those in the NCBI database identified six distinct genotypes. Conclusions Evaluations conducted in this study indicate a significant relationship between the identified genotypes in Lori-Bakhtiari sheep and traits such as birth weight, daily weight gain, cholesterol (p<0.05), and rump width (p<0.01).

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