University of Copenhagen researchers have mapped a West Greenlandic narwhal's genetic family history and made a surprising discovery: genetic variation in narwhals is very low compared against other mammals.
University of Copenhagen researchers have mapped a West Greenlandic narwhal's genetic family history and made a surprising discovery: genetic variation in narwhals is very low compared against other mammals. The discovery calls into question the notion that high genetic diversity is needed for a species to survive. Instead of facing extinction, the narwhal population has been stable, until recently. How the narwhal has survived for as long as it has remains a mystery.
Why mess with a recipe for success? For narwhals, this appears to be the case. Researchers at the Natural History Museum of Denmark have DNA sequenced the genome of a narwhal from West Greenland, and opened a window to the past million years of its evolutionary history. The results suggest that genetic diversity among narwhals has been consistently low throughout the entire period. Nevertheless, the species has survived through to the present day.
"The narwhal has incredibly low genetic variation across its genome compared to other mammals, both in and beyond the Arctic. This is surprising, as high genetic diversity is normally associated with greater odds of long-term survival," explains Associate Professor Eline Lorenzen, who headed the study.
Roughly 170,000 narwhals currently inhabit Arctic waters surrounding Greenland, Canada, Svalbard and Russia. The genetic analyses demonstrate that their population has been stable for an exceptionally long period of time, and that their numbers have grown since the last ice age – although several areas are currently experiencing population declines due to hunting.
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Image via University of Copenhagen.
