Washington: Researchers have claimed to have found how whales successfully adapted to ocean environment.
Whales roam throughout all of the world`s oceans, living in the water but breathing air like humans. At the top of the food chain, whales are vital to the health of the marine environment, whereas 7 out of the 13 great whale species are endangered or vulnerable.
In this study, researchers conducted de novo sequencing on a minke whale with 128x average depth of coverage, and re-sequenced three minke whales, a fin whale (Balaenoptera physalus), a bottlenose dolphin, and a finless porpoise (Neophocaena phocaenoides).
The adaptation of whale to ocean life was notably marked by resistance to physiological stresses caused by a lack of oxygen, increased reactive oxygen species, and high salt level.
Researchers investigated a number of whale-specific genes that were strongly associated with stress resistance, such as the peroxiredoxin ( PRDX) family, O-linked N-acetylglucosaminylation ( O-GlcNAcylation).
The results revealed that the gene families associated with stress-responsive proteins and anaerobic metabolism were expanded.
In this study, researchers provided evidence to support that there is an increased ratio of reduced glutathione/glutathione disulfide when suffering hypoxic or oxidative stress.
Minke whales and other Mysticeti whale species grow baleen instead of teeth. It`s previously reported that the genes ENAM, MMP, and AMEL might play a role in tooth enamel formation and biomineralization.
This study showed that these genes may be pseudogenes with early stop codons in the baleen whales.
The study has been published online in journal Nature Genetics.