The role of additive and non-additive genetic effects during animal contests in the beadlet sea anemone Actinia equina

Lead Research Organisation: UNIVERSITY OF EXETER
Department Name: Biosciences

Abstract

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Technical Summary

Aggression is very common in humans and non-humans. A full understanding of why aggression occurs, and persists, so widely across animal taxa requires that we also consider its evolution. A longstanding question is why variation in aggressive behaviour and fighting ability (RHP) is maintained in animal populations. Game theory proposes that negative frequency dependent selection can maintain a stable mix of strategies, but it does not account for the potentially complex genetic architecture that underlies variation in aggression. In particular indirect as well as direct genetic effects are likely to influence an individual's aggressive behaviour. Therefore we will study the role of additive and non-additive genetic effects (i.e. genotype-by-genotype interactions, GxG) for the first time in the context of animal contests. We have chosen the beadlet sea anemone Actina equina as out study system. These animals fight readily and reproduce asexually, allowing for the repeated contests between genotype pairs necessary for robust statistical analysis using mixed-effects models. GxG interactions will be studied from the perspective of both current and previous opponents, both of which are contribute to an individual's social environment. Recent studies show that consistent among individual and among genotype variation are partly dependent on within-individual consistency, and we will also assess the effects of genotype on this spontaneous intra-individual variation in aggression. Finally, we will use AFLP analysis to directly measure relatedness between genotype pairs, enabling us to assess how GxG interactions are modified by genetic similarity. The overall aim of this project is to resolve a longstanding question in animal behaviour; how is variation in aggression maintained in animal populations? We will use approaches from research on animal contests, animal personality, quantitative genetics and population genetics to answer this question.

Planned Impact

The wider impact of this research is likely to be in the areas of (1) enhancing the research capacity, knowledge and skills of businesses and organisations and (2) increasing public awareness and understanding of science.

Animal science is strongly aligned with research into methods of refining livestock production and the welfare of farmed animals (including aquaculture). Despite current advances in cloning vertebrates and potential future use of cloning as a means of enhancing livestock production, no research has yet been conducted on the potential for inter-individual aggression levels to be influenced by genotype by genotype interactions. Knowledge of genotype by genotype interaction effects could be used to enhance welfare and production by selecting individuals with compatible genotypes (i.e. combinations that will produce low aggression) for housing. Basic knowledge of whether this is likely to be a potential issue will be provided by our studies on a highly tractable model system. If genotype by genotype interactions influence aggression levels in sea anemones this would point to the need for future studies of additive and non-additive genetic contributions to aggression in other animals including livestock animals as well as ornamental animals used in the aquarium trade.

There is a huge public thirst for new information about the natural world, and in this project we will make new discoveries about a species that anyone living in the UK can readily encounter in its natural setting, and where related species are easily accessible globally. Furthermore, the core ideas underlying the research, the links between genes and behaviour, are of fundamental interest to the public and the concepts of animal personality and aggression are proven to attract the attention of the media. Therefore, this project is provides excellent opportunities for public engagement with science, in particular demonstrating the importance of fundamental science that can nevertheless be applied to tackling wider issues.

Publications

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Lane SM (2020) Analysis of direct and indirect genetic effects in fighting sea anemones. in Behavioral ecology : official journal of the International Society for Behavioral Ecology

 
Description This award is connected to a larger grant awarded to M. Briffa (PI) at Plymouth. He is reporting in full on the findings and output of the wider project which tests fundamental theory about the determinants of escalation and outcome in animal contests. My involvement was as a coi (with separate JES form tied to this specific award) overseeing a genetic component of the study.

It has long been known that contest outcomes depend on genes influencing traits such as body size or weaponry (e.g. ho
Exploitation Route The results have some potential implications for agriculture and aquaculture, although it is important to acknowledge that the use of anemones here was intended to allow us experimental tractability to determine what might be important. Extrapolating the results to aggressive interactions in, for instance, chickens, farmed salmon or pigs is not sensible at present.

The project has, however, shown that simple organisms such as anemones can be used to study basic principles and test core (gener
Sectors Agriculture, Food and Drink