The aim of this study was to analyze variability within casein genes in dairy and non-dairy sheep breeds. In total, 30 single nucleotide polymorphisms (SNPs), one indel, and one microsatellite, all located in milk protein genes (CSN1S1, CSN1S2, CSN2, CSN3) were genotyped. The analysis included 478 samples derived from 14 different European (Italy and Germany) and African (Nigeria and Cameroon) sheep breeds, and 32 European Mou on (EM) samples. Allele and genotype frequencies were calculated using PopGene V 1.31. Intragenic haplotypes were calculated for each casein gene using the expectation and maximization (EM) algorithm of the HAPLOTYPE procedures of SAS® 9.3. Frequencies of casein haplotypes between dairy and non-dairy breeds were compared using a principal component analysis (PCA) with the PRINCOMP procedure of SAS® 9.3. Out of 30 SNP analysed 3 were found monomorphic in all breeds. Moreover in a further SNP T allele could be considered rare as it occurred only in Sopravissana breed at a very low frequency (0.0161). Considering the casein genes it was not possible to nd clear differences in haplotype distribution between dairy and non-dairy breeds. Some haplotypes of one of the four genes were xed or rare in some breeds, whereas in the same breeds different haplotype distribution was found within the other genes. Only 2 haplotypes were found in EM and at least 4 breeds showed more than 7 haplotypes. The most frequent haplotype occurred in all breeds including EM. The lowest Ho values were observed for the three African breeds. In the future, association studies should be made including milk performance traits by phenotyping the animal material.
Genetic diversity within casein genes in European and African sheep breeds
S Chessa;
2015
Abstract
The aim of this study was to analyze variability within casein genes in dairy and non-dairy sheep breeds. In total, 30 single nucleotide polymorphisms (SNPs), one indel, and one microsatellite, all located in milk protein genes (CSN1S1, CSN1S2, CSN2, CSN3) were genotyped. The analysis included 478 samples derived from 14 different European (Italy and Germany) and African (Nigeria and Cameroon) sheep breeds, and 32 European Mou on (EM) samples. Allele and genotype frequencies were calculated using PopGene V 1.31. Intragenic haplotypes were calculated for each casein gene using the expectation and maximization (EM) algorithm of the HAPLOTYPE procedures of SAS® 9.3. Frequencies of casein haplotypes between dairy and non-dairy breeds were compared using a principal component analysis (PCA) with the PRINCOMP procedure of SAS® 9.3. Out of 30 SNP analysed 3 were found monomorphic in all breeds. Moreover in a further SNP T allele could be considered rare as it occurred only in Sopravissana breed at a very low frequency (0.0161). Considering the casein genes it was not possible to nd clear differences in haplotype distribution between dairy and non-dairy breeds. Some haplotypes of one of the four genes were xed or rare in some breeds, whereas in the same breeds different haplotype distribution was found within the other genes. Only 2 haplotypes were found in EM and at least 4 breeds showed more than 7 haplotypes. The most frequent haplotype occurred in all breeds including EM. The lowest Ho values were observed for the three African breeds. In the future, association studies should be made including milk performance traits by phenotyping the animal material.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
