Figure 1.

Conservation of orphan and R–M MTs (A) Probability density of the degree of conservation (defined as the proportion of genomes—within the genus—in which a MT is conserved) of class 1 (red, solid line) and class 2 orphan MTs (magenta, solid line) and R–M MTs (blue solid line). The dashed lines, in colours matching that for the real data set described above, show the distributions for an example simulation in which random sets of genes were chosen as controls such that the number of genes from each genome equals that in the real data set. (B) Distribution of P-values (Wilcoxon test; negative logarithm, base10) comparing the distribution of the degree of conservation of genes for the three types of MTs with that from random simulations (n = 30). A dotted horizontal line is drawn at P = 0.01.