Single strand conformation polymorphism analysis in the Sarda breed sheep POU1F1 gene

The ovine POU1F1 gene, localized in chromosome 1, contains 6 exons and 5 introns and in several mammals species its association with different productive traits has been shown. The aim of the study was to study the POU1F1 gene nucleotide sequence to highlight possible polymorphisms and, if present, their relationships with milk productive traits in Sarda sheep breed. The study has been conducted on 140 Sarda lactating ewes, in their third to fifth lactation. A blood sample was collected from each ewe for DNA extraction. Genomic DNA (100 ng) has been used for the amplification of the exons 1, 2, 3 and 6. For each exon, 10 amplicons random selected were sequenced and compared with those present in Data bases. Then all the PCR products were denatured and analyzed using Single Strand Conformation Polymorphism (SSCP) method. SSCP analysis of exons 1, 2 and 3 did not shown any variation. Instead a G to an A substitution in the 3’ UTR region of exon 6 was found in one animal. The POU1F1 gene sequence showed a high variability in the “Churra da terra Quente” sheep, a recent Portuguese breed with a great genetic and productive variability. This productive variability in the daily milk production, that ranges from 0.25 to 1.5 l, is not associated with management differences but may be linked to a high genetic variability. However no relationship between POU1F1 polymorphism and milk productive traits was found in this breed. Conversely in Sarda sheep the individual milk production levels are very comparable, due to genetic selection for increased milk yield. This fact could have led to an indirect selection of the POU1F1 gene causing its lack of variability. However, it would be necessary to extend the study to the remaining exons and to other gene fragments (introns, promoter) to expanding knowledge about this gene in Sarda breed sheep.