Evolved KEGG pathway in cetaceans

Evolved KEGG pathway in cetaceans

 Perhaps the most marked environmental adaptation for a whale is deep diving, which induces hypoxia. Under hypoxic conditions, reactive oxygen species (ROS) are generated by several cellular mechanisms. Glutathione is a well-known antioxidant that prevents damage to important cellular components by ROS. Seven glutathione metabolism pathway genes (GPX2, ODC1, GSR, GGT6, GGT7, GCLC and ANPEP) showed cetacean-specific amino acid changes; these changes were present in the four minke whales, a fin whale, two bottlenose dolphins and a porpoise. GSR in the glutathione metabolism pathway was also positively selected in the dolphin. It is known that the increased expression of GSR increases the antioxidant capacity of cells. Furthermore, functional categories, such as antioxidant activity (GO:0016209, P = 0.010, 13 genes) and oxidoreductase activity (GO:0016491, P = 0.00000035, 162 genes), were enriched in the minke whale genome.