Association between KISS1 gene and growth traits in two Middle Eastern sheep breeds: the Iranian Karakul and the Iraqi Awassi

The KISS1 gene, also known as the KiSS-1 metastasis suppressor gene, is recognized in humans for its ability to suppress metastasis of various carcinomas. It encodes a protein that has emerged as a promising molecular target for the management of metastatic disease and has shown potential for clinical utility. However, studies investigating the association between this gene and growth traits in sheep are lacking. This study aimed to assess the possible biomarker capacity of KISS1 by evaluating its association with growth traits in two economically important sheep in the Middle East, the Iranian Karakul and the Iraqi Awassi. Genotyping was conducted using PCR-single-stranded conformation polymorphism (SSCP), and the variation of the KISS1 gene was linked with several growth traits at three-month intervals starting from birth until one year of age. In a total of 180 Karakul sheep and 200 Awassi sheep, only one SNP (72G > C) was detected, which had not been previously reported in sheep. The identified novel SNP showed significant associations with the majority of growth traits measured at the ages of three, six, nine, and twelve months. At the age of three months onward, lambs with GG genotypes showed higher growth trait values compared with those with the GC and CC genotypes, respectively. Due to these remarkable associations, the 72G > C SNP is suggested as a promising marker for growth traits in both breeds. This is the first study that demonstrated the importance of KISS1 as a possible tool for evaluating growth traits in Awassi and Karakul breeds with the possibility of being applied to other breeds via large-scale investigations.