Genetic variation of goat Y chromosome in the Sardinian population

Sardinian goat population is commonly considered a crossbred of autochthonous animals with improved Mediterranean breeds, mainly the Maltese. It has been demonstrated by using autosomal microsatellites that the Sardinian goats can be divided into three subpopulations: Sardinian, crossbred with Maltese, and Maltese. The aim of this study was to evaluate sequence variation at Y chromosome in Sardinian bucks and to integrate autosomal microsatellites data. Blood from 190 bucks from 68 farms spread in the main Sardinian goat farming areas was sampled. Three ECONOGENE project primer pairs plus an additional one corresponding to a total of 7 SNPs were used. For all common SNPs, the most frequent allele corresponded to the ECONOGENE one. The additional analysed SNP showed allelic frequencies similar to the other markers. The comparison with haplotypes based on the 6 common SNPs showed that the Sardinian most frequent haplotype corresponded to the predominant one in Central Europe. Results of this study showed that the Sardinian goat population has 8 haplotypes resulting in a large diversity of paternal lineages. The next step will be linking autosomal information to Y chromosome data. In fact, up to date, it seems unfeasible to detect recent upgrading breeds by using Y chromosome variation only

One polymorphism at the Stearoyl CoA Desaturase (SCD) gene is associated to CLA content of sheep milk fat

On OAR 22 a highly significant QTL affecting the rate of desaturation of vaccenic acid (VA) to conjugated linoleic acid (CLA) in the mammary gland of sheep was found segregating on four dairy sheep families of a Sardinian x Lacaune back-cross population. The most likely location of the QTL was 35 cM corresponding to Stearoyl CoA Desaturase (SCD) gene location on the Australian Sheep Gene Map. The aim of this work was finding mutations along the SCD gene associated with the CLA/VA variability in sheep milk. The sequencing of a large part of the gene in the four informative sires allowed identifying one SNP in intron 4 (3295 C>T relative to Capra hircus SCD gene, GenBank Acc. no. AH011188). The sequencing of high and low phenotypic tails’ progeny from the most significant family showed a strong association of the found mutation with the CLA/VA variability

Association between ovine Stearoyl-CoA desaturase gene polymorphism and the conjugated linoleic acid content in sheep milk fat: results of a positional candidate gene study

The aims of the study were the fine mapping of one QTL found for Conjugated Linoleic Acid (CLA) and Vaccenic Acid (VA) ratio on OAR 22 in a Sardinian x Lacaune backcross population and validating the QTL in the Sardinian pure breed. Fine-mapping was performed adding 7 microsatellites to the three previously used. The new QTL detection analysis highlighted the presence of one highly significant (p<0.00001) QTL with the most probable location at 35 cM corresponding to the position of the stearoyl coenzyme A desaturase (SCD) gene on the available maps. SCD represents a strong positional candidate gene since is a key enzyme responsible for ∆9-desaturation of fatty acids. The sire and twenty-eight ewes of the most significant family were selected to sequence the Scd gene: fourteen from the low and fourteen from the high tails of CLA and VA ratio. The sire resulted heterozygous C/T at intron 4 (3295 C>T on GenBank AH011188 Capra hircus SCD gene). Among the 14 animals of the high tail 13 inherited the T allele. Among the 14 animals of the low tail 13 inherited the C allele. The 3 other informative sires resulted homozygous C/C. The found QTL resulted segregating in three 7/8 families. All the 7/8 sires resulted homozygous C/C at the SNP found. Even if one significant polymorphism has been found, it does not allow the immediate application of MAS or GAS. However, the high significance of the QTL suggests that the undergoing studies will be successful to detect the causative mutations

Additional file 1 of Advances in understanding the genetic architecture of antibody response to paratuberculosis in sheep by heritability estimate and LDLA mapping analyses and investigation of candidate regions using sequence-based data

Additional file 1: Figure S1. Quantile–quantile (Q–Q) plot corresponding to the LDLA mapping that was carried out based on CAR. The plot contains the observed − log10(p-value) obtained by the LDLA analysis (y axis) plotted against the expected − log10(p-value) (x axis). Figure S2. Quantile–quantile (Q–Q) plot corresponding to the LDLA mapping that was carried out based on SP. The plot contains the observed − log10(p-value) obtained by the LDLA analysis (y axis) plotted against the expected − log10(P-value) (x axis)