Meerkats genetically adapt to a species-specific form of tuberculosis. This has been demonstrated for the first time by an international research team led by Ulm University in a long-term study. The scientists also find that climate change in the Kalahari Desert exerts additional selection pressure on the animals. The combination of infection pressure and climate change is putting meerkats under increasing evolutionary stress. The study's results have been published in Nature Ecology Evolution.
How do wild animal diseases affect the genetics of their hosts in the long term - and what is the role of climate change? A team of researchers from Germany, Switzerland, the United Kingdom and Australia, led by Professor Simone Sommer from the Institute of Evolutionary Ecology and Conversation Genomics at Ulm University, investigated this in a long-term study based on genetic data collected over two decades from more than 1,500 meerkats, together with data on the spread of tuberculosis. The researchers were able to show for the first time that the disease alters the immune-genetic diversity of the animals. The tuberculosis infection, which is caused by the bacterium Mycobacterium suricattae, greatly shortens the life expectancy of meerkats and makes it more difficult for them to reproduce.
The study focuses on the so-called MHC genes (Major Histocompatibility Complex), which play an important role in the recognition of pathogens and the immune defence of all vertebrates. The researchers made a surprising discovery: over the course of the study, a certain gene variant developed from a supposed risk factor into a survival advantage. While this variant was initially more common in infected animals, adaptation processes in wild animals later led to a longer life and more offspring - a clear indication of dynamic selection processes triggered by pathogens. "Our data impressively shows how infectious diseases can trigger evolutionary changes in wild animal populations in real time," explains Dr Nadine Müller-Klein, first author of the study and scientist at the Institute of Evolutionary Ecology and Conversation Genomics. Until now, such adaptations had mainly been hypothesised on the basis of laboratory studies.
Climate change increases spread of tuberculosis
Particularly alarming: climatic changes, especially rising temperatures and changes in rainfall combined with heat waves, significantly increase the spread and progression of tuberculosis. The results emphasise the growing importance of wildlife diseases in the context of global warming. "Climate change is not only altering habitats, but also the way in which infectious diseases affect the health of wild animals," explains Ulm co-author Dr Dominik Melville. "Lack of food and heat stress deplete energy reserves - which is particularly critical when an animal is already weakened or infected."
Professor Simone Sommer adds: "Twenty years ago, we already realised that preserving genetic diversity would be crucial for species conservation. Now we recognise how immunogenetic diversity in particular plays a central role - it can significantly reinforce the disease resilience of wild animals in the face of climate change." The study also shows positive prospects for them. At the same time, the wildlife ecologist warns: "The results emphasise the need to consider genetic diversity as an integral part of modern species conservation strategies."
The findings of this study do not only concern meerkats. They significantly contribute to fundamental research in evolutionary biology, while also providing important impetus for wildlife health and conservation strategies in the face of climate change. The study was made possible by the extensive collection of data from one of the world's best documented wildlife populations in the Kuruman River Reserve in the Kalahari and decades of research led by Professor Marta Manser from the University of Zurich and Professor Tim Clutton-Brock from the University of Cambridge.
The study was funded by the German Research Foundation (SO 428/15-1, Simone Sommer): "Influence of immunogenetic diversity, gut microbiota and social networks on the susceptibility and epidemiology of tuberculosis in wild meerkats".
Publication reference:
Müller-Klein N, Risely A, Wilhelm K, Riegel V, Manser M, Clutton-Brock T, Silver L, Santos PSC, Melville DW, Sommer S (2025): Twenty-years of Tuberculosis-driven selection shaped the evolution of meerkat MHC. Nature Ecology & Evolution.
DOI: https://doi.org/10.1038/s41559-025-02837-x
Further information:
Dr Nadine Müller-Klein, Institute of Evolutionary Ecology and Conversation Genomics, Ulm University, Mail: nadine.mueller-klein(at)uni-ulm.de
Media contact: Christine Liebhardt