Single nucleotide polymorphisms at the imprinted bovine insulin-like growth factor 2 (IGF2) locus are associated with dairy performance in Irish Holstein-Friesian cattle

Abstract

The imprinted insulin-like growth factor 2 gene (IGF2) encodes a fetal mitogenic hormone protein (IGF-II) and has previously been shown to be associated with performance in dairy cattle. In this study we assessed genotype-phenotype associations between four single nucleotide polymorphisms (SNPs) located within the bovine IGF2 locus on chromosome 29 and a range of performance traits related to milk production, animal growth and body size, fertility and progeny survival in 848 progeny-tested Irish Holstein-Friesian sires. Two of the four SNPs (rs42196909 and IGF2.g-3815A> G), which were in strong linkage disequilibrium (r 2 =0 . 995), were associated with milk yield (Pf0 . 01) and milk protein yield (Pf0 . 05); the rs42196901 SNP was also associated (Pf0 . 05) with milk fat yield. Associations (Pf0 . 05) with milk fat percentage and milk protein percentage were observed at the rs42196901 and IGF2.g-3815A> G SNPs, respectively. The rs42196909 and IGF2.g-3815A> G SNPs were also associated with progeny carcass conformation (Pf0 . 05), while an association (Pf0 . 01) with progeny carcass weight was observed at the rs42194733 SNP locus. None of the four SNPs were associated with body size, fertility and progeny survival. These findings support previous work which suggests that the IGF2 locus is an important biological regulator of milk production in dairy cattle and add to an accumulating body of research showing that imprinted genes influence many complex performance traits in cattle.Keywords: Bos, cattle, genetic imprinting, IGF2, performance traits, single nucleotide polymorphism.Genetic studies have shown that the paternally inherited and maternally inherited genomes in eutherian mammals are not functionally equivalent. This is most aptly illustrated by genetic (or ' genomic') imprinting, a form of epigenetic regulation that results in the preferential expression of an allele from one of the two parentally inherited chromosomes in a parent-of-origin manner (McGrath & Solter, 1984;Surani et al. 1984). To date, nearly 100 imprinted mammalian genes have been identified, many of which play important roles in fetal growth and development (Bartolomei, 2009;Feil, 2009).The insulin-like growth factor 2 gene (IGF2), which encodes a fetal mitogenic protein (IGF-II) structurally related to insulin (O'Dell & Day, 1998), has been the most extensively studied imprinted mammalian gene owing to its pivotal role in the regulation of embryonic development and relationship to disease (Reik et al. 2000;Rodriguez et al. 2007). In mammals, IGF2 is expressed preferentially from the paternally inherited allele in most embryonic tissues and forms a conserved imprinted gene cluster with the reciprocally imprinted, non-protein coding H19 gene, which is highly expressed in embryonic and fetal tissue but whose function remains unclear (Bartolomei et al. 1991; Rachmilewitz et al. 1992; Giannoukakis et al. 1993; *For correspondence; e-mail : david.magee@ucd.ie Feil et al. 1998;McLaren & Montgomery, 1999;Dindot et al. 2004a ;Dindot et al. 200...

Epigenetics and developmental programming of welfare and production traits in farm animals

“…protein percentage, somatic cell counts) and growth (e.g. carcass weight, conformation, rump depth; Magee et al 2010;Berkowicz et al 2011). There is also some evidence of allelic switching of imprinted IGF2R in SCNT cloned bovine fetuses where the paternal allele is imprinted in one tissue whereas the maternal allele is imprinted in another tissue (SuteevunPhermthai et al 2009).…”

Association between IGF2 and CYP21 gene polymorphisms and characteristics of economic interest in Nellore cattle

“…The SNP RFLP/MboII analyzed in this study is present in exon 6 of the IGF2 gene, which is considered a regulatory region due to its location in the 5'UTR; these regions can be targeted by regulatory proteins with a substantial number of mRNA structural motifs, which have been identified in transcriptional and post-transcription regulation of gene expression (Martins da Silva et al, 2008). The IGF2 gene encodes a fetal mitogenic protein (IGF-II) structurally related to insulin, and has been the most extensively studied imprinted mammalian gene owing to its pivotal role in the regulation of embryonic development and relationship to disease (Berkowicz et al, 2010). The effect of the T/C allele replacement for IGF2 was considered to be statistically significant (3%) in Bonferroni test results.…”

Plasma exosome profiles from dairy cows with divergent fertility phenotypes

“…The same methods could be used to predict desirable traits in animals, such as likelihood of pregnancy success. The use of epigenetic biomarkers is still in its infancy but already some positive results have been obtained (Magee et al, 2010;Berkowicz et al, 2011). We believe that pregnancy rates can be improved by use of protein and epigenetic biomarkers that can be delineated and then used prognostically for positive reproductive performance and, potentially, to monitor the effectiveness of intervention strategies, such as nutritional or anti-inflammatory approaches.…”