Partitioning Phenotypic Variance Due to Parent-of-Origin Effects Using Genomic Relatedness Matrices

Despite the health-related benefits of exercise, many people do not engage in enough activity to realize the rewards, and little is known regarding the genetic or environmental components that account for this individual variation. We created and phenotyped a large G4 advanced intercross line originating from reciprocal crosses between mice with genetic propensity for increased voluntary exercise (HR line) and the inbred strain C57BL/6J. G4 females (compared to males) ran significantly more when provided access to a running wheel and were smaller with a greater percentage of body fat pre- and postwheel access. Change in body composition resulting from a 6-day exposure to wheels varied between the sexes with females generally regulating energy balance more precisely in the presence of exercise. We observed parent-of-origin effects on most voluntary wheel running and body composition traits, which accounted for 3–13% of the total phenotypic variance pooled across sexes. G4 individuals descended from progenitor (F0) crosses of HR♀ and C57BL/6J♂ ran greater distances, spent more time running, ran at higher maximum speeds/day, and had lower percent body fat and higher percent lean mass than mice descended from reciprocal progenitor crosses (C57BL/6J♀ × HR♂). For some traits, significant interactions between parent of origin and sex were observed. We discuss these results in the context of sex dependent activity and weight loss patterns, the contribution of parent-of-origin effects to predisposition for voluntary exercise, and the genetic (i.e., X-linked or mtDNA variations), epigenetic (i.e., genomic imprinting), and environmental (i.e., in utero environment or maternal care) phenomena potentially modulating these effects.

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Estimates of variances due to parent of origin effects for weights of Australian beef cattle

Animal Production Science ◽

10.1071/an11195 ◽

2012 ◽

Vol 52 (4) ◽

pp. 215 ◽

Cited By ~ 8

Author(s):

Karin Meyer ◽

Bruce Tier

Keyword(s):

Animal Model ◽

Large Scale ◽

Relationship Matrix ◽

Phenotypic Variance ◽

Maternal Parent ◽

Hereford Cattle ◽

Paternal Parent ◽

Parent Of Origin ◽

Origin Effects ◽

Set Up

Estimates of variances due to differential expression of paternally and maternally derived genes can be obtained from animal model type analyses by fitting appropriate gametic effects. This is feasible for large-scale analyses, because the inverse of the gametic relationship matrix can be set up directly from a list of pedigrees. We present a series of analyses applying such a model to large sets of records for birth, weaning, yearling and final weights of Australian Angus and Hereford cattle. On one hand, results show that maternal genetic effects on these traits are largely confounded with maternal parent of origin effects, so that it is difficult to reliably separate the respective variance components. On the other hand, paternal parent of origin effects tend to act similarly to sire × herd effects so that estimates of their variance are inflated by any effects not modelled and contributing to such apparent interaction. Fitting an animal model with both parent of offspring effects, maternal genetic and permanent environmental effects as well as sire × herd and maternal grand-sire × herd of origin of dam interactions as additional random effects yielded estimates of the variance due to paternal parent of origin effects of 5–7% of the phenotypic variation for birth and weaning weights and of 0–1% for yearling and final weights. Corresponding estimates for maternal parent of origin effects were 0–11% for birth and weaning weights and 7–8% for yearling and final weights, while sire and maternal grand-sire interaction effects explained from 0 to 4% of the phenotypic variance.

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