Association of insulin-like growth factor-1 gene with maternal growth, reproduction and conformation traits in Harnali sheep

The present study explored the association between a point mutation (g.857G>A) in the IGF-1 gene and performance traits in Harnali Sheep. Genomic DNA was extracted from 110 Harnali sheep using an Automated Maxell RSC DNA/RNA purification system. A 294 bp fragment, covering the 5' flanking region of the IGF-1 gene, was amplified with specific primers. The resulting PCR product, harboring the g.857G>A mutation, was digested with the Hae II enzyme to determine genotypes. The frequency of the A allele of the IGF-1 gene was higher (0.59) in the studied Harnali sheep population, with the GA genotype being the most prevalent (0.64). The presence of the A allele was associated with higher body weights, suggesting its potential as a selection criterion for improving flock performance. Furthermore, the GA genotype was linked to a lower average age at first lambing (727.93 days) compared to the GG genotype (753.08 days). The A allele was linked to higher body weights, while the GA genotype was associated with a lower age at first lambing. These findings highlight the potential of these genetic markers for improving breeding strategies and enhancing flock performance. However, validation on larger samples is warranted.