Inbreeding shapes tuberculosis progression in female adult badgers (Meles meles)

In Focus: Beton, C. H., Delahay, R. J., Smith, F. A. P., Robertson, A., McDonald, R. A., Young, A. J., Burke T. A., & Hodgson, D. (2018). Inbreeding intensifies sex‐ and age‐dependent disease in a wild mammal. Journal of Animal Ecology, 87, 1497‐1499. https://doi.org/10.1111/1365-2656.12878 Increasing crossbreeding of relatives promotes inbreeding which, in turn, can cause a reduction in fitness and the emergence of a phenomenon known as inbreeding depression. Benton et al., used the badger (Meles meles)—Mycobacterium bovis model system to study the relationship between inbreeding, disease, ageing and sex. A link between multilocus homozygosity (general effect) and TB progression (measured as antibody response to infection) and between homozygosity at specific loci (local effect) and TB progression were established in this study, highlighting the importance of host genetic background in determining host disease outcomes, and thus on shaping disease dynamics in wild populations. Moreover, the authors demonstrated for the first time in a natural population that this positive association might be modulated by sex and age. In infected individuals, inbreeding only affects disease progression in adult females. Increasing crossbreeding of relatives promotes inbreeding, which often causes a reduction in fitness. However, few studies in wild populations quantify the inbreeding effects on host disease phenotype. This study uses the badger tuberculosis model system to show that inbreeding influences tuberculosis progression, and this effect might be modulated by sex and ageing.