Analysis of polymorphism within POU1F1 gene in relation to milk production traits in dairy Sarda sheep breed.

The ovine POU1F1 gene is localized on chromosome 1 and it contains five introns and six exons. In different mammalian species some mutations in different exons are associated with different production traits. The aim of our research was to study the POU1F1 gene nucleotide sequence to detect possible polymorphisms and their relationships with milk productive traits in Sarda breed sheep. The study had been conducted on 140 ewes, 4 or 5 years old coming from a farm located in Sardinia. All the animals were multiparous, lactating and in their third to fifth lactation. Individual milk yield had been recorded monthly and for each sample fat, protein, casein, lactose, and somatic cell count values were analysed. A jugular blood sample was collected from each ewe to perform genomic DNA extraction. PCR, SSCP and sequencing analysis were carried out to examine the six exons to highlight possible SNPs. One-way ANOVA was used to analyse association of variants with milk yield and/or its composition. Two novel SNP were found: 121 C>T in the 5'UTR of the fourth intron fragment and 249 G>A in the 3'UTR of the sixth exon fragment. The statistical analysis did not shown association between milk productive traits and the found polymorphisms. However, further investigations about the promoter region or the prophet genes, like the PROP-1, could clarify its exact role in regulating the productive traits in sheep.