PCR-SSCP analysis of GH gene in Sarda goats: a high variability and its preliminary effects on dairy performances

The growth hormone (GH) gene can be utilized as a major gene because in various domestic livestock its polymorphisms have been associated to milk traits. The aim of this research was to investigate single-strand conformation polymorphism (SSCP) in the exon 3 of gGH (goat GH) gene and to evaluate the possible association with milk traits in Sarda goat breed. Forty-four primiparous lactating goats were randomly chosen, and the productive parameters (milk yield, fat, protein, and lactose percentage) of three consecutive lactations were monitored. The exon 3 of the gGH gene was PCR amplified and the resulting products were analysed by SSCP. Six conformational patterns were detected. The sequencing of SSCP patterns revealed the occurrence of six nucleotide changes, two of which determined amino acid changes in the deduced protein sequence. A preliminary comparative analysis of the productive traits related to three lactations with the genomic profiles derived from the SSCP analysis was performed with the ANOVA statistical method. SSCP polymorphic patterns in exon 3 were associated (P<0.01) with milk yield, fat and protein percentages, and with lactose content (P<0.05). These findings may be used for marker assisted selection in Sarda goat, in order to improve dairy production, preserving genetic diversity of the population.