Analyzing the genetic variation of dairy sarda and spanish meat ovine breeds

The aims of this thesis were to investigate if variation at regulatory sites of the milk protein genes is associated with traits of economic interest in dairy Sarda sheep, as well as the genetic characterization of Spanish meat ovine breeds. Seven hundred and sixty Sarda sheep were genotyped with a multiplex TaqMan® assay of 29 SNPs found by us in the four casein genes and three previously reported SNPs in the LALBA and BLG genes. A high level of polymorphism (1 SNP every 200bp) was revealed and significant associations between CSN1S2 and CSN3 genotypes and milk protein and casein contents, while CSN1S1 and CSN2 genotypes were significantly associated with curd firming time. A total of 140 individuals belonging to the Xisqueta, Ripollesa, Segureña, Gallega, Roja Mallorquina and Canaria de Pelo breeds were genotyped with the Infinium 50K Ovine SNP BeadChip (Illumina). This dataset was merged with 50K genotypes of other five Spanish breeds (Churra, Ojalada, Castellana, Latxa and Rasa Aragonesa). Population genetics analyses revealed that Canaria de Pelo, Roja Mallorquina, Latxa and Churra were clearly differentiated populations. We performed a second experiment aiming to estimate the amount of shared vs breed-specific variation in five Spanish breeds through a RNA-seq approach. Our results showed a similar amount of shared vs pool-specific variants. Moreover, the number of pool-specific SNPs in Canaria de Pelo and Xisqueta was 2-5 fold higher than in the others breeds