Abstract #370
Section: Breeding and Genetics (orals)
Session: Breeding and Genetics - Breeding Strategies and Male Fertility
Format: Oral
Day/Time: Tuesday 4:30 PM–4:45 PM
Location: Room 207/208
Session: Breeding and Genetics - Breeding Strategies and Male Fertility
Format: Oral
Day/Time: Tuesday 4:30 PM–4:45 PM
Location: Room 207/208
# 370
Investigation of genetic variation in global DNA methylation in bull semen and its relationship with semen quality and fertility parameters.
Y. He*1, C. Maltecca1, F. Tiezzi1, A. Canovas2, S. Bhattarai3, S. McKay3, 1Department of Animal Science, North Carolina State University, Raleigh, NC, 2Department of Animal Biosciences, University of Guelph, Guelph, ON, Canada, 3Department of Animal and Veterinary Sciences, University of Vermont, Burlington, VT.
Key Words: DNA methylation, semen quality, genetic variation
Investigation of genetic variation in global DNA methylation in bull semen and its relationship with semen quality and fertility parameters.
Y. He*1, C. Maltecca1, F. Tiezzi1, A. Canovas2, S. Bhattarai3, S. McKay3, 1Department of Animal Science, North Carolina State University, Raleigh, NC, 2Department of Animal Biosciences, University of Guelph, Guelph, ON, Canada, 3Department of Animal and Veterinary Sciences, University of Vermont, Burlington, VT.
As an important mediator of gene expression, epigenetic modifications, such as DNA methylation, affect transcription and cause variation among phenotypes. DNA methylation has received much attention in studies of male fertility in human and livestock. In bulls, although epigenetic modifications have been found to significantly influence semen quality, the mechanisms and patterns underlying these modifications are not fully understood. Therefore, the objectives of the study were to determine the effects of global methylation on sperm quality parameters and to investigate genetic variability in semen DNA methylation among sire families (n = 27) and paternal lines (n = 4). Semen samples and semen quality parameters were obtained from bulls (n = 402) selected based on pedigree and relevance of phenotypic information. From each sample, DNA extraction was performed and global methylation was measured on 50–200 ng of DNA using the MethylFlash Methylated DNA Quantification Kit (Colorimetric) with absorbance readings measured at 450 nm. A linear mixed model was utilized to predict traits related to sperm morphology, motility, and viability, using global sperm methylation and sires as fixed effects. Additionally, variance components and heritability (h2) were estimated for global methylation of overall sire families and paternal lines respectively. Mean methylation of the sampled bulls ranged from 0.383 to 1.994%-5mC, and from 0.982 to 1.204%-5mC across sire families and paternal lines respectively. For the analyzed semen parameters, methylation was a significant effect for motility and normal spermatozoa (P < 0.10), while sire was a significant effect for viability (P < 0.10). Estimated variance for sire family and paternal line was 0.065 and 0.018 respectively. Heritability estimates for global methylation were 0.179 for sire family variance and 0.053 for paternal line variance. The current study has established the first association between overall methylation and semen quality parameters, contributing to the selection of a new criterion for fertility in dairy bulls.
Key Words: DNA methylation, semen quality, genetic variation
