Evolution of human innate immunity

Several components of the human innate immune system can trace their origins back to ancient bacterial defense strategies (Wein & Sorek, 2022, Nat. Rev. Immuno.). Nonetheless, the evolutionary arms race between host and pathogens leads to a constant need of evolutionary change that makes sequence-based homology searches difficult. Recent technological advances made it possible to search for deep evolutionary conservation. These advances allow us for the first time to systematically investigate protein ancestry. 

Innate immune mechanisms shared between eukaryotes and prokaryotes (Figure: Wein & Sorek, 2022, Nat. Rev. Immuno.).