A genome scan for milk production traits in dairy goats reveals two new mutations in Dgat1 reducing milk fat content

Abstract

The quantity of milk and milk fat and proteins are particularly important traits in dairy livestock. However, little is known about the regions of the genome that influence these traits in goats. We conducted a genome wide association study in French goats and identified 109 regions associated with dairy traits. For a major region on chromosome 14 closely associated with fat content, the Diacylglycerol O-Acyltransferase 1 (DGAT1) gene turned out to be a functional and positional candidate gene. The caprine reference sequence of this gene was completed and 29 polymorphisms were found in the gene sequence, including two novel exonic mutations: R251L and R396W, leading to substitutions in the protein sequence. The R251L mutation was found in the Saanen breed at a frequency of 3.5% and the R396W mutation both in the Saanen and Alpine breeds at a frequencies of 13% and 7% respectively. The R396W mutation explained 46% of the genetic variance of the trait, and the R251L mutation 6%. Both mutations were associated with a notable decrease in milk fat content. Their causality was then demonstrated by a functional test. These results provide new knowledge on the genetic basis of milk synthesis and will help improve the management of the French dairy goat breeding program.

Goat domestication and breeding: a jigsaw of historical, biological and molecular data with missing pieces

“…) and milk fat content (Martin et al . ). Whole‐genome sequences of 15 native goats and 11 crossbred Korean goats and selection analysis based on linkage disequilibrium (LD) and allele frequency spectrum statistics (Lee et al .…”

Genome wide association analysis on semen volume and milk yield using different strategies of imputation to whole genome sequence in French dairy goats

“…Milk yield (MY) in kg was also measured as detailed by Martin et al [5,6] and analyzed. Daughter Yield Deviations (DYD) were computed for males with at least 10 daughters with records (Table 1).…”

“…Genome-wide association studies (GWAS) are commonly used to unravel the genetic architecture of complex traits. The GoatSNP50 BeadChip has led to the detection of a few Quantitative Trait Loci (QTL) regions for milk and type traits in French Alpine and Saanen breeds [5][6][7][8]. One causal mutation has been identified [5] and a large zone on chromosome 19 needs to be refined in Saanen goats given the width of the confidence interval, the multiplicity of traits associated with the same region of the chromosome and as no straightforward functional candidate gene was identified [6].…”

“…The GoatSNP50 BeadChip has led to the detection of a few Quantitative Trait Loci (QTL) regions for milk and type traits in French Alpine and Saanen breeds [5][6][7][8]. One causal mutation has been identified [5] and a large zone on chromosome 19 needs to be refined in Saanen goats given the width of the confidence interval, the multiplicity of traits associated with the same region of the chromosome and as no straightforward functional candidate gene was identified [6]. The use of sequence data, rather than chip data, for fine QTL mapping has proved more accurate in various species, such as cattle [9,10] and poultry [11].…”

A mini-atlas of gene expression for the domestic goat (Capra hircus) reveals transcriptional differences in immune signatures between sheep and goats

“…expressed. The expression level of Diacylglycerol O-Acyltransferase 1 (DGAT1) which is 516 associated with milk fat content in dairy goats (Martin et al, 2017) did not vary hugely across 517 the tissues sampled ( Fig 4F), although there was slightly higher expression in some tissues 518 (e.g. colon and liver) relative to immune tissues (e.g.…”