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Biology

Comparative Immune Strategies Across Vertebrate Lineages

Quick fact

Jawless vertebrates (lampreys and hagfish) evolved a completely different adaptive immune system from jawed vertebrates: instead of immunoglobulin-based antibodies, they use variable lymphocyte receptors (VLRs) built from leucine-rich repeat modules—a striking case of convergent evolution.

Why this is interesting

Your immune system is a time-traveling assassin that never forgets a foe—but a shark's immune system is a blunt, fast-reacting weapon, and a frog's is a bare-bones 'generic patch'. How did such different defense strategies evolve?