When a narwhal mom and a beluga dad love each other very much...

Skull morphology suggested it, and DNA sequencing confirms it: narlugas are real

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close up of beluga whale looking at camera

 Photo by saanv vav on Unsplash

In 1990 a Danish Biologist noticed an odd narwhal skull in West  Greenland. The man who had hunted the animal described it as a mix between a narwhal and a beluga. These two types of whales were known to have synchronous mating seasons and close evolutionary history, which added up to a plausible story, but the origin of this hybrid creature could not be confirmed with the technology available.

Flash forward almost 30 years later and we finally have the technology to figure out whether narwhal-beluga whale hybrids really exist. Scientists from the Natural History of Denmark used Next Generation Sequencing (NGS), the results of which were recently published in Nature Scientific Reports. NGS allows researchers to sequence genomes in parallel, instead of one base at a time. This comes in handy when you’re working with a 31 million base-pair genome! But the authors didn’t just sequence the potential hybrid's genome, they also sequenced eight belugas and eight narwhals from West Greenland for comparison. 

Collecting DNA from the 30-year-old hybrid skull was a task in and of itself: bone and teeth contain much less DNA then tissues do, and so the researchers had to collect 0.5 g of bone dust for each  sample. Even from that, they were only able to cover 5% of the total  narwhal-beluga genome. Five percent of 31 million is still over 1 million base pairs. When the researchers compared these sequences to the two whale species, they observed similarities to both narwhals and  belugas. They also used NGS to determine which of the whale species - narwhal or beluga - contributed mitocondrial DNA, which is only passed down by mothers. Their final determination was that the hybrid was indeed a narwhal-beluga mix, with a narwhal mother. Some have even dubbed the animal a "narluga."

There are still so many mysteries about the world's biodiversity to be solved, and NGS will be key in unlocking them!