Abstract Introduction Leptin, a class I helical cytokine, regulates growth, appetite, energy homeostasis and reproductive functions in fish. The leptin gene ( lep ) is a candidate gene for growth trait influence in both farm animals and teleost fish. Material and Methods This study investigated variations in the lep gene and their associations with growth-related traits in European sea bass ( Dicentrarchus labrax ) using DNA sequencing. Results Twelve novel single-nucleotide polymorphisms (SNPs) were identified in the first and second introns and the third exon of the gene, including a non-synonymous third exon variant (g.11004767C>T) causing an arginine-to-tryptophan substitution. This locus was significantly associated with multiple growth traits, including total and fillet weights and standard, body and post-anal lengths (P-value T) suggested its potential effects on local protein conformation and receptor binding. Conclusion These findings indicate that lep gene polymorphisms, particularly the g.11004714G>A locus and specific haplotypes, are associated with growth variability in European sea bass. The identified SNPs and haplotypes may facilitate molecular marker–assisted selection in growth performance breeding programmes in economically important aquaculture species.
Emel Özcan Gökçek (Sat,) studied this question.