Figure 4

Comparison of intron densities of nuclear-encoded mitochondrial genes and ancestral eukaryotic genes. Green, mitochondrial genes; red, ancestral nuclear genes. The bar lengths correspond to the intron density. The p-value is based on a chi-squared test comparing the frequency of introns in nuclear-encoded mitochondrial genes and ancestral eukaryotic genes to the expected frequency calculated using the number of positions in nuclear-encoded mitochondrial genes and ancestral eukaryotic genes. The p-values for individual species are as follows: Anopheles gambiae (0.74), Arabidopsis thaliana (0.01), Babesia bovis (0.91), Branchiostoma floridae (0.76), Caenorhabditis elegans (0.82), Ciona intestinalis (0.69), Cryptococcus neoformans (0.27), Dictyostelium discoideum (0.94), Drosophila melanogaster (0.67), Gallus gallus (0.91), Gibberella zeae (0.41), Homo sapiens (0.90), Monosiga brevicollis (0.38), Oryza sativa (0.05), Ostreococcus taurii (0.53), Physcomitrella patens (0.00), Saccharomyces cerevisiae (0.22), Schistosoma mansoni (0.55), Schizosaccharomyces pombe (0.90), Strongylocentrotus purpuratus (0.54), Thalassiosira pseudonana (0.31), Ustilago maydis (0.12), Vitis vinifera (0.09).