摘要
Background： Recent technological advances in genomics have allowed the genotyping of cattle through single nucleotide polymorphism（SNP） panels. High-density SNP panels possess greater genome coverage and are useful for the identification of conserved regions of the genome due to selection, known as selection signatures（SS）. The SS are detectable by different methods, such as the extended haplotype homozygosity（EHH）; and the integrated haplotype score（i HS）, which is derived from the EHH. The aim of this study was to identify SS regions in Canchim cattle（composite breed）, genotyped with high-density SNP panel.Results： A total of 687,655 SNP markers and 396 samples remained for SS analysis after the genotype quality control. The i HS statistic for each marker was transformed into pi HS for better interpretation of the results.Chromosomes BTA5 and BTA14 showed pi HS 〉 5, with 39 and nine statistically significant SNPs（P 〈 0.00001）,respectively. For the candidate selection regions, i HS values were computed across the genome and averaged within non-overlapping windows of 500 Kb. We have identified genes that play an important role in metabolism,melanin biosynthesis（pigmentation）, and embryonic and bone development.Conclusions： The observation of SS indicates that the selection processes performed in Canchim, as well as in the founder breeds（i.e. Charolais）, are maintaining specific genomic regions, particularly on BTA5 and BTA14. These selection signatures regions could be associated with Canchim characterization.
Background： Recent technological advances in genomics have allowed the genotyping of cattle through single nucleotide polymorphism（SNP） panels. High-density SNP panels possess greater genome coverage and are useful for the identification of conserved regions of the genome due to selection, known as selection signatures（SS）. The SS are detectable by different methods, such as the extended haplotype homozygosity（EHH）; and the integrated haplotype score（i HS）, which is derived from the EHH. The aim of this study was to identify SS regions in Canchim cattle（composite breed）, genotyped with high-density SNP panel.Results： A total of 687,655 SNP markers and 396 samples remained for SS analysis after the genotype quality control. The i HS statistic for each marker was transformed into pi HS for better interpretation of the results.Chromosomes BTA5 and BTA14 showed pi HS 〉 5, with 39 and nine statistically significant SNPs（P 〈 0.00001）,respectively. For the candidate selection regions, i HS values were computed across the genome and averaged within non-overlapping windows of 500 Kb. We have identified genes that play an important role in metabolism,melanin biosynthesis（pigmentation）, and embryonic and bone development.Conclusions： The observation of SS indicates that the selection processes performed in Canchim, as well as in the founder breeds（i.e. Charolais）, are maintaining specific genomic regions, particularly on BTA5 and BTA14. These selection signatures regions could be associated with Canchim characterization.
基金
the Brazilian Agricultural Research Corporation(EMBRAPA)for providing the data used in this study
the Sao Paulo Research Foundation(FAPESP)(grant 2013/09050-0,2014/02253-6,2015/08939-0,and 2013/19335-2,respectively)
supported by a fellowship from the National Council of Technological and Scientific Development(CNPq)
