Research Information System
The Plant and Animal Genome XXVI Conference (PAG), San Diego, United States Of America, 13 - 17 January 2018, pp.1
Sheep are economically important with worldwide distribution of approximately 1 billion animals. Growth-associated genetic variants, such as a TNXB charged amino acid substitution E2004G and a silent DGAT1 single nucleotide polymorphism (rs409119650), could improve profitability of sheep production. However, both were identified in single research reports utilizing small groups of sheep. We evaluated 896 U.S. sheep to investigate association of TNXB E2004G and DGAT1 rs409119650 with growth and lifetime production. For TNXB E2004G, glutamic acid homozygotes had greater live body weights in spring and fall at ages 3 and 4 (all P ≤ 0.05) and greater milk scores at ages 3 and 4 (P < 0.05). The milk scoring system used was economically relevant since it had previously been shown to correlate with lamb growth. Thus, these data provide the first report of an association with an economically important milk measure for TNXB E2004G, as well as confirming a prior association of the ancestral glutamic acid allele with increased growth. While DGAT1 rs409119650 was associated with increased 4-year-old live body weight and lifetime greasy fleece weight (P < 0.05), these results should be interpreted with caution given the low observed minor allele frequency (4.9%) and additional datasets are needed to fully evaluate utility of DGAT1 rs409119650. Overall, the observed TNXB E2004G association with increased live weight in divergent breeds and multiple countries may suggest a useful role in selective breeding programs, but careful optimization of breeding strategies may be valuable to balance growth rates and mature body size appropriately.