Evidence for parent-of-origin effects on genetic variability of beef traits1

Abstract

Imprinted genes are involved in many aspects of development in mammals, plants, and perhaps birds and may play a role in growth and carcass composition of slaughter animals. In the presence of genomic imprinting the expression and, consequently, the effect on the phenotype of maternal and paternal alleles are different. For genetic evaluation genomic imprinting can be accounted for by incorporating 2 additive genetic effects per animal; the first corresponds to a paternal and the second to a maternal expression pattern of imprinted genes. This model holds whatever the mode of imprinting may be: paternal or maternal, full or partial, or any combination thereof. A set of slaughter data from 65,233 German Simmental fattening bulls was analyzed with respect to the relative importance of the genetic imprinting variance. Besides slaughter weight, net daily BW gain, and killing out percentage, there were 22 other traits describing the carcass composition. The latter traits were evaluated by automatic video-imaging devices and were composed of weights of valuable cuts as well as fat and meatiness grade. The number of ancestors in the pedigree was 356,880. Genomic imprinting significantly contributed to the genetic variance of 10 traits, with estimated proportions between 8 and 25% of the total additive genetic variance. For 6 of these traits, the maternal contribution to the imprinting variance was larger than the paternal, whereas for all other traits the reverse was true. Fat grade only showed a paternal contribution to the imprinting variance. Estimates of animal model heritabilities of automatic video-imaging-recorded carcass traits ranged between 20 and 30%.

Sources of sire-specific genetic variance for birth and weaning weight in Bruna dels Pirineus beef calves

“…These results partially agreed with those reported by Engellandt and Tier (2002) and Neugebauer et al (2010) in Gelbvieh and Simmental cattle, respectively, although contradictory results were also available (Reinsch et al, 1999). The influence of the Y chromosome was previously highlighted by Kieffer and Cartwright (1968) and Schoeman (1989), who reported that even the morphology of this chromosome (i.e.…”

“…However, in mice, Schwenker and Maxon (1986) and Bü nger et al (1995) reported significant influences from the Y chromosome on growth, BW and testis weight. A similar scenario was found for the imprinting phenomenon in beef cattle where available -E-mail: joaquim.casellas@uab.cat results restricted to original researches conducted on German Gelbvieh (Engellandt and Tier, 2002) and Simmental cattle (Neugebauer et al, 2010); imprinting variability was revealed on several carcass traits. Furthermore, some imprinted quantitative trait loci have been detected in livestock species for growth and fatness traits (De Koning et al, 2001a and2011b).…”

“…Neugebauer et al, 2010) where the influence of the maternal environment must be almost null, we focused our analyses on weight traits that were clearly influenced by the permanent environment provided by the cow (Quintanilla et al, 1999). Within this context, the current parameterization for paternal imprinting could not be generalized to the maternal component because maternal imprinting and direct maternal effects were confounded and the final model was not identifiable.…”

“…Within this context, the current parameterization for paternal imprinting could not be generalized to the maternal component because maternal imprinting and direct maternal effects were confounded and the final model was not identifiable. Indeed, we preferred to accumulate all maternal contributions into the d vector assuming that, if existed, maternal effect through milk and both maternal imprinting and effects from the mitochondrial DNA would accumulate there (Neugebauer et al, 2010).…”

“…Contradictory results about the impact of the Y chromosome on carcass traits in Simmental cattle were provided by Reinsch et al (1999) and Neugebauer et al (2010), although large effects were discarded. However, in mice, Schwenker and Maxon (1986) and Bü nger et al (1995) reported significant influences from the Y chromosome on growth, BW and testis weight.…”