Conserved orthology in mitochondrial genomes of distantly related nematodes

Identification of orthologous segments plays a very important role in comparative genomics studies. In the present study, we have identified orthologous segments shared between Radopholus similis and 15 other nematodes. Complete genomes of 16 nematodes were used for the study. OSfinder was used to find the orthologous segments shared between R. similis and other 15 nematodes. Orthologous segments were visualized with the help of GTK powered Murasaki Visualizer (GMV) programme. Extremely AT rich genome of the burrowing nematode R. similis, which has the largest mitochondrial genome, was found to have orthologous segments from start position, 4 to end position 16791 with 15 nematodes. Brugia malayi, Dirofilaria immitis, Onchocerca volvulus, and Xiphinema americanum share similar orthologous segment with that of R. similis. The mitochondrial genome analysis revealed the presence of conserved gene locations in mitochondrion and the close evolutionary relationship of nematodes belonging to different clades and different parasitic habitats. This study has many practical implications like reconstruction of ancestral genome of nematode and calculation of evolutionary time.