Figure 1

MAP kinase sequence is conserved in parthenogenetic nematodes. A: Phylogenetic tree of the phylum Nematoda. Species mentioned in this study are indicated and mapped to their respective clade. Clades 1-7 are collapsed into one branch. Colour assigns parthenogenetic (violet) or hermaphroditic reproduction (grey) through all figures. B: Phylogenetic analysis of MAP kinase genes from hermaphroditic (C. elegans and Acrobeloides (herma)) and parthenogenetic (A. nanus and D. coronatus) nematodes using maximum likelihood (model: RtREV). Significances at branches are indicated. All newly isolated nematode MAP kinase genes belong, like C. elegans MPK-1, to the Erk1/2 subfamily of MAP kinases. They group in line with the inferred phylogenetic position, not according to the underlying reproductive mode. C. elegans MPK-2, to which a function has not been ascribed so far, clusters to the Erk5 subfamily. C: Sequence alignment of the activation loop of human and nematode Erk1/2 MAP kinase proteins. Amino acids T202 and Y204 (numbering after human Erk1), which get phosphorylated during activation, are indicated (red). The epitope recognised by the antibody against active MAP kinase, including the dual phosphorylation motif, is highly specific for Erk1/2 family members and perfectly conserved in nematode MAP kinases irrespective of the reproductive mode.