Understanding the evolution of immune genes in jawed vertebrates

Driven by co-evolution with pathogens, host immunity continuously adapts to optimize defence against pathogens within a given environment. Recent advances in genetics, genomics and transcriptomics have enabled a more detailed investigation into how immunogenetic variation shapes the diversity of immune responses seen across domestic and wild animal species. However, a deeper understanding of the diverse molecular mechanisms that shape immunity within and among species is still needed to gain insight into—and generate evolutionary hypotheses on—the ultimate drivers of immunological differences. Here, we discuss current advances in our understanding of molecular evolution underpinning jawed vertebrate immunity. First, we introduce the immunome concept, a framework for characterizing genes involved in immune defence from a comparative perspective, then we outline how immune genes of interest can be identified. Second, we focus on how different selection modes are observed acting across groups of immune genes and propose hypotheses to explain these differences. We then provide an overview of the approaches used so far to study the evolutionary heterogeneity of immune genes on macro and microevolutionary scales. Finally, we discuss some of the current evidence as to how specific pathogens affect the evolution of different groups of immune genes. This review results from the collective discussion on the current key challenges in evolutionary immunology conducted at the ESEB 2021 Online Satellite Symposium: Molecular evolution of the vertebrate immune system, from the lab to natural populations.

Biotechnology and Biological Sciences Research Council

Grant/Award Number: BB/K004468/1, BB/M011224/1, BB/ N023803/1 and BB/V000756/1

Department for Environment, Food and Rural Affairs

UK Government, Grant/ Award Number: OD0221

Deutsche Forschungsgemeinschaft, Grant/ Award Number: 437857095

Grantová Agentura České Republiky, Grant/Award Number: 19-20152Y

Grantová Agentura, Univerzita Karlova, Grant/Award Number: 646119

H2020 European Research Council, Grant/Award Number: ERC-2019- StG- 853272- PALAEOFARM

University of Oxford, Grant/Award Number: 0005172; Ministerstvo Školství, Mládeže a Tělovýchovy

Grant/Award Number: SVV 260684/2023; Ministerstvo Zemědělství, Grant/Award Number: MZE-RO0723

National Institutes of Health, Grant/Award Number: 1R01AI123659-01A1; Univerzita Karlova v Praze

Grant/Award Number: START/SCI/113 with reg. no. CZ.02.2.69/0.0/0.0/19_; Vetenskapsrådet, Grant/Award Number: 2020-04285