Genetic Diversity and Immune Response in Wildlife Populations

Genetic diversity underpins the capacity of wildlife populations to resist and adapt to infectious threats in changing environments. Variation at immune loci influences susceptibility to pathogens and determines population resilience. Central to this process are components of the innate immune system, notably toll‐like receptors (TLRs), which detect conserved microbial motifs and initiate rapid defence mechanisms. Studies across mammals, birds and reptiles reveal that demographic events—such as bottlenecks, fragmentation and translocations—can erode functional diversity at these loci, while pathogen‐driven selection can maintain or enhance variation when population sizes permit. Understanding the balance between drift and selection at immune genes yields insights into disease emergence, conservation translocations and management of endangered taxa. Integrating high‐throughput sequencing, longitudinal monitoring and experimental assays has clarified how allele frequency shifts relate to survival, reproductive success and receptor functionality. This synthesis highlights the global significance of immunogenetic diversity, emphasises its role in conservation planning and illustrates practical applications such as identifying candidate loci for monitoring population health and guiding translocation strategies.

Research from Nature Portfolio

Recent work comparing innate immune receptor genes in free‐ranging apex predators has revealed contrasting patterns of diversity among sympatric species. High‐throughput sequencing of selected TLRs in two large felids shows that modern populations of one species harbour markedly reduced receptor‐gene variation relative to historic specimens and to a co‐occurring congenor, suggesting recent declines have narrowed allelic repertoires essential for pathogen recognition. In parallel, foundational investigation of multiple TLRs in a wild rodent species demonstrated clear signatures of balancing selection at receptors interacting with bacterial components, whereas those recognising viral motifs exhibited directional selection and low polymorphism. Functional associations between specific TLR alleles and pathogen susceptibility further underscore the complexity of immune gene evolution and its dependence on the nature of microbial challenges.

Genetic Diversity and Immune Response in Wildlife Populations publication trend

The graph below shows the total number of articles in genetic diversity and immune response in wildlife populations across all publications each year (not limited to Nature Index journals).

Technical terms

Genetic diversity: Variation in DNA sequences among individuals within a population, critical for adaptive potential.

Innate immune system: The organism’s first line of defence, comprising receptors and cells that rapidly recognise common pathogen features.

Toll‐like receptors (TLRs): A family of transmembrane proteins that detect conserved microbial molecules and trigger inflammatory responses.

Balancing selection: An evolutionary process that maintains multiple alleles at a locus within a population, often through heterozygote advantage or fluctuating selection.

Directional selection: Selection favouring one allele over others, leading to a shift in allele frequency toward the advantageous variant.

References

1. Diversity of selected toll-like receptor genes in cheetahs (Acinonyx jubatus) and African leopards (Panthera pardus pardus). Scientific Reports (2024).
2. Signatures of balancing selection in toll-like receptor (TLRs) genes – novel insights from a free-living rodent. Scientific Reports (2018).
3. Contemporary evolution of the innate immune receptor gene TLR3 in an isolated vertebrate population. Molecular Ecology (2021).
4. Evidence of Pathogen-Induced Immunogenetic Selection across the Large Geographic Range of a Wild Seabird. Molecular Biology and Evolution (2020).