Figure 1.

Maximum-likelihood tree for 52 genome-sequenced nematode species. The tree was constructed based on the concatenated alignment of 17 orthologous proteins present in a single copy in these genomes as described in the Methods. Bootstrap scores for each node are indicated at the branch points. The bar indicates 0.2 changes per position. The major nematode groups at different phylogenetic levels are labeled. The tree was rooted using the outgroup species shown.