Lemurs are the most distantly related non-human primates. A Research Article by Anne Averdam and colleagues in this issue of PLoS Genetics (see Averdam et al., 10.1371/journal.pgen.1000688) shows that lemurs differ considerably from "higher" primates in receptors of natural killer (NK) cells and their ligands. Instead of KIR or Ly49 genes, lemurs substantially expanded and diversified CD94/NKG2 receptors. Remarkably, this novel system of polymorphic and diverse receptors points to combinatorial diversity as a mechanism to increase the NK cell receptor repertoire of lemurs, a finding that was previously unknown for NK cells.

Image Credit: Manfred Eberle, www.phocus.org (German Primate Center - Leibniz Institute for Primate Research, Germany)