Where do your bones come from? Shark genome study offers insights.

Researchers have mapped the genome of the elephant shark, and they say it helps explain the genetic basis of how bones form.

It turns out that studying a boneless animal can help explain the genetic basis of bones.

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An international group of researchers has sequenced the genome of the elephant shark, "a curious-looking fish with a snout that resembles the end of an elephant's trunk." The species, which despite its name is not actually a shark, is a member ofthe family of the world's oldest-living jawed vertebrates.

But why elephant sharks?

The elephant shark was selected for sequencing because of its compact genome, which is one-third the size of the human genome, according to a press release by The Genome Institute at Washington University School of Medicine.

Like actual sharks, the elephant shark, which belongs to the order chimaera, has a "skeleton" made of cartilage rather than bone, making it an oddity on the evolutionary tree.

After comparing the shark genome with those of other vertebrates with bones, researchers noticed that the elephant shark lacked a family of genes that are crucial for bone formation. They confirmed this by removing a member of this gene family in zebrafish, a tropical freshwater fish. It was observed that a gene's absence correlated with a reduction in bone formation in zebrafish, highlighting the importance of this gene family in making bones.

"So now we know what genes are missing in elephant sharks and from that we learned about this new gene family, which is important in bone formation," Patrick Minx from The Genome Institute at Washington University School of Medicine, told the Monitor. Therefore, the findings have important implications for understanding bone diseases, he says.

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Where do your bones come from? Shark genome study offers insights.