Evolutionary Analyses Suggest a Function of MxB Immunity Proteins Beyond Lentivirus Restriction
Fig 4
Recombination substantially impacts the BSE and GTPase domain of MxA and MxB via gene conversion.
(A) GARD analysis suggests that recurrent gene conversion/recombination events between Mx paralogs have resulted in at least two segments of the gene with distinct evolutionary histories (evidence ratio >100). Supported recombination breakpoints (***, P < 0.01; **, P < 0.05) and the location of GARD segments are shown on a linear schematic of the human MxA protein, colored as in Fig 1B (also see S4 Fig). (B, C) We used PHYML to generate maximum-likelihood phylogenies of the two GARD-defined segments of MxA and MxB from selected primate, carnivore and ungulate species. Gene conversion that homogenized GARD segment A in the shared ancestor of each mammalian order (black circles) or in specific lineages (white circles) is indicated in panel B (also see S4 Fig). Note that a full-length MxA-MxB phylogeny is similar to that of GARD segment B. Please refer to S4 Dataset.