title: Signatures of selection identify loci associated with milk yield in sheep.
abstract: BACKGROUND
  Identification of genomic regions that have been targets of selection for phenotypic traits is one of the most challenging areas of research in animal genetics, particularly in livestock where few annotated genes are available. In this study a genome-wide scan using the Illumina SNP50K Beadchip was performed in the attempt to identify genomic regions associated with milk productivity in sheep. The ovine genomic regions encoding putative candidate genes were compared with the corresponding areas in Bos taurus, as the taurine genome is better annotated.
  
  
  RESULTS
  A total of 100 dairy sheep were genotyped on the Illumina OvineSNP50K Beadchip. The Fisher's exact test of significance of differences of allele frequency between each pair of the two tails of the distribution of top/worse milk yielders was performed for each marker. The genomic regions where highly divergent milk yielders showed different allele frequencies at consecutive markers was extracted from the OAR v3.1 Ovine (Texel) Genome Assembly, and was compared to the corresponding areas in Bos taurus, allowing the detection of two genes, the Palmdelphin and the Ring finger protein 145. These genes encoded non-synonymous mutations correlated with the marker alleles.
  
  
  CONCLUSIONS
  The innovation of this study was to show that the DNA genotyping with the Illumina SNP50K Beadchip allowed to detect genes, and mutations in the genes, which have not yet been annotated in the livestock under investigation.
authors.affiliation: Consiglio per la Ricerca e la sperimentazione in Agricoltura, via Salaria 31, Monterotondo 00015, Italy. bianca.moioli@entecra.it.
authors.forename: Bianca
authors.initials: B
authors.lastname: Moioli
authors.forename: Maria Carmela
authors.initials: MC
authors.lastname: Scatà
authors.forename: Roberto
authors.initials: R
authors.lastname: Steri
authors.forename: Francesco
authors.initials: F
authors.lastname: Napolitano
authors.forename: Gennaro
authors.initials: G
authors.lastname: Catillo
mesh_terms: D000483:Alleles; D000818:Animals; D004268:DNA-Binding Proteins / Q000235:genetics; D005091:Exons; D005260:Female; D005787:Gene Frequency; D056426:Genetic Loci; D016678:Genome; D005838:Genotype; D007774:Lactation / Q000235:genetics*; D008565:Membrane Proteins / Q000235:genetics; D008892:Milk / Q000378:metabolism*; D020641:Polymorphism, Single Nucleotide; D012641:Selection, Genetic; D012756:Sheep / Q000235:genetics*; D034561:Sheep, Domestic / Q000235:genetics
chemical_list: D004268:DNA-Binding Proteins; D008565:Membrane Proteins; C434124:Palmd protein, mouse