According to the new research, not only do some species of whales get darker with sun exposure, incurring DNA damage in their skin just like us, they also accumulate damage to the cells in the skin as they get older.
Over three years, the team of marine biologists from Trent University, Canada and Universities in La Paz and Queretaro, Mexico, took skin samples from the backs of three species of whales during their annual migration, which occurs between February and April the whales move to the sunnier Gulf of California, along the northwest coast of Mexico.
Blue whales have a very pale pigmentation. During migration time the team found a seasonal change with the pigment in their skin increasing as well as mitochondrial DNA damage. This internal damage to the mitochondria, the engines of the cells, is caused by UV exposure and is what we find in sunburned human skin.
Sperm whales with their distinctive rounded foreheads have a darker pigmentation, also migrate between February and April to the Gulf of California, but have a different lifestyle. They spend long periods at the surface between feeds and are therefore, exposed to more sun and UV.
The scientists found the sperm whales had a different mechanism for protecting themselves from the sun, triggering a stress response in their genes.
In contrast, the darkest whales, the deeply pigmented fin whales, were found to be resistant to sun damage showing the lowest prevalence of sunburn lesions in their skin.
To carry out the research the Newcastle University team had to develop an analysis which allowed three whale genomes to be analysed at the same time, a difficult task as whales have very different sequences. This research is the first time that whales have been studied at a genetic level linking to migratory patterns and genetic damage.
The research has been published in Nature journal.
--ANI (Posted on 31-08-2013)