Indirect genetic effects contribute substantially to heritable variation in aggression-related traits in group-housed mink (Neovison vison)

Abstract

BackgroundSince the recommendations on group housing of mink (Neovison vison) were adopted by the Council of Europe in 1999, it has become common in mink production in Europe. Group housing is advantageous from a production perspective, but can lead to aggression between animals and thus raises a welfare issue. Bite marks on the animals are an indicator of this aggressive behaviour and thus selection against frequency of bite marks should reduce aggression and improve animal welfare. Bite marks on one individual reflect the aggression of its group members, which means that the number of bite marks carried by one individual depends on the behaviour of other individuals and that it may have a genetic basis. Thus, for a successful breeding strategy it could be crucial to consider both direct (DGE) and indirect (IGE) genetic effects on this trait. However, to date no study has investigated the genetic basis of bite marks in mink.Result and discussionA model that included DGE and IGE fitted the data significantly better than a model with DGE only, and IGE contributed a substantial proportion of the heritable variation available for response to selection. In the model with IGE, the total heritable variation expressed as the proportion of phenotypic variance (T2) was six times greater than classical heritability (h2). For instance, for total bite marks, T2 was equal to 0.61, while h2 was equal to 0.10. The genetic correlation between direct and indirect effects ranged from 0.55 for neck bite marks to 0.99 for tail bite marks. This positive correlation suggests that mink have a tendency to fight in a reciprocal way (giving and receiving bites) and thus, a genotype that confers a tendency to bite other individuals can also cause its bearer to receive more bites.ConclusionBoth direct and indirect genetic effects contribute to variation in number of bite marks in group-housed mink. Thus, a genetic selection design that includes both direct genetic and indirect genetic effects could reduce the frequency of bite marks and probably aggression behaviour in group-housed mink.

Prediction of reduction in aggressive behaviour of growing pigs using skin lesion traits as selection criteria

“…selecting for reduced SL24h could theoretically result in increased aggression; Ellen et al, 2014). Previous studies suggest a positive correlation between direct and social effects for aggressive behaviour, meaning that animals with a low genetic propensity to become involved in aggression also have a low chance of being attacked (Wilson et al, 2011;Alemu et al, 2014). Negative correlations between social and direct effects have been found for dominance traits (Wilson et al, 2009;Sartori and Mantovani, 2012), however, social effects accounted for little of the variation in these studies.…”

Increased developmental density decreases the magnitude of indirect genetic effects expressed during agonistic interactions in an insect

“…() and Alemu et al . () found a positive correlation between DGEs and IGEs on aggression in deer mice and mink ( Neovison vison ), respectively. In addition to the study of aggression in animals, in Eucalyptus trees ( Eucalyptus globulus ), the competition among neighboring trees also led to strongly negative correlations between DGEs and IGEs for growth across age categories (Costa e Silva et al.…”

“…), mink ( Neovison vison ) (Alemu et al. ), Drosophila melanogaster (Saltz ), and southern field crickets ( Gryllus bimaculatus ) (Santostefano et al. ).…”

“…; Alemu et al. ) versus depress (Santostefano et al. ) conspecific aggression, respectively, implying that IGEs exist because individuals modify their aggression as a function of the level of aggression expressed in interaction partners.…”

Social structure and indirect genetic effects: genetics of social behaviour

“…Ecological interactions in plant systems contribute to the size and fitness-related traits of neighbours (Mutic & Wolf, 2007;Wolf, Mutic & Kover, 2011;Andersson, 2014), which has led to accounting for IGEs in the optimization of breeding programs (Muir, 2005). Examples of phenotypes under shared genetic control from the animal kingdom include social dominance interactions in red deer Cervus elaphus (Wilson et al, 2011), antipredator behaviour in Poecilia reticulate guppies (Bleakley & Brodie, 2009), growth rate in medaka Oryzias latipes (Ruzzante & Doyle, 1991), female choosiness in Pacific field crickets Teleogryllus oceanicus (Bailey & Zuk, 2012), egg-laying date variance in common gulls Larus canus (Brommer & Rattiste, 2008), as well as aggression in pigs Sus scrofa (Camerlink et al, 2013) and mink Neovison vison (Alemu et al, 2014). Yet another ubiquitous category is intergenerational IGEs best exemplified by maternal effects in plants (Roach & Wulff, 1987), insects (Mousseau et al, 2009), and animals (Bernardo, 1996).…”