Sex-specific impact of inbreeding on pathogen load in the striped dolphin

Gkafas, Georgios A.; de Jong, Menno; Exadactylos, Athanasios; Raga, Juan Antonio; Aznar, Francisco J.; Hoelzel, A. Rus

Abstract

The impact of inbreeding on fitness has been widely studied and provides consequential inference about adaptive potential and the impact on survival for reduced and fragmented natural populations. Correlations between heterozygosity and fitness are common in the literature, but they rarely inform about the likely mechanisms. Here, we investigate a pathology with a clear impact on health in striped dolphin hosts (a nematode infection that compromises lung function). Dolphins varied with respect to their parasite burden of this highly pathogenic lung nematode (Skrjabinalius guevarai). Genetic diversity revealed by high-resolution restriction-associated DNA (43 018 RADseq single nucleotide polymorphisms) analyses showed a clear association between heterozygosity and pathogen load, but only for female dolphins, for which the more heterozygous individuals had lower Sk. guevarai burden. One locus identified by RADseq was a strong outlier in association with parasite load (heterozygous in all uninfected females, homozygous for 94% of infected females), found in an intron of the citron rho-interacting serine/threonine kinase locus (associated with milk production in mammals). Allelic variation at the Class II major histocompatability complex DQB locus was also assessed and found to be associated with both regional variation and with pathogen load. Both sex specificity and the identification of associating functional loci provide insight into the mechanisms by which more inbred individuals may be more susceptible to the infection of this parasite. This provides important insight towards our understanding of the impact of inbreeding in natural populations, relevant to both evolutionary and practical conservation considerations.

Citation

Gkafas, G. A., de Jong, M., Exadactylos, A., Raga, J. A., Aznar, F. J., & Hoelzel, A. R. (2020). Sex-specific impact of inbreeding on pathogen load in the striped dolphin. Proceedings of the Royal Society B: Biological Sciences, 287(1922), Article 20200195. https://doi.org/10.1098/rspb.2020.0195

• Journal Article Type: Article
• Acceptance Date: Feb 14, 2020
• Online Publication Date: Mar 10, 2020
• Publication Date: Mar 4, 2020
• Deposit Date: Apr 5, 2020
• Publicly Available Date: Apr 7, 2020
• Journal: Proceedings of the Royal Society B: Biological Sciences
• Print ISSN: 0962-8452
• Electronic ISSN: 1471-2954
• Publisher: The Royal Society
• Peer Reviewed: Peer Reviewed
• Volume: 287
• Issue: 1922
• Article Number: 20200195
• DOI: https://doi.org/10.1098/rspb.2020.0195
• Public URL: https://durham-repository.worktribe.com/output/1304944