DNA study unravels secrets of bactrian camels

Sky-high blood glucose levels, a diet loaded with salt and a tendency to pack away fat sounds like a recipe for a health disaster in a human. But in a Bactrian camel, these are adaptations that may help it survive in some of the driest, coldest and highest regions of the world.

Scientists in China said on Tuesday they had sequenced the DNA of the wild bactrian camel, a threatened species with an extraordinary ability to survive in extreme conditions.

The genetic code of Camelus bactrianus ferus reveals 20,821 genes, many of them providing the metabolic tools to cope with days without food and water and a diet based on tough desert vegetation.

Bactrian camels are descendants of even-toed ungulates which diverged from a common ancestor around 55-60 million years ago, they found.

The DNA book could shed light on the camel’s ‘remarkable salt tolerance and unusual immune system,’ said the study, published in the journal Nature Communications .

Wild bactrian camels live in the deserts of northwestern China and southwestern Mongolia, where they endure fierce heat and bitter cold, aridity and sparse grazing. Camels consume eight times more salt than cattle or sheep and have twice the blood glucose levels of other ruminants, yet do not develop diabetes or hypertension. They also make unique disease-fighting proteins called heavy-chain antibodies, which interest pharmaceutical engineers.

ALL IN THE BLOOD:-

Camels, as ruminants like cattle and sheep, digest food by chewing the cud. But many of the Bactrian genome’s rapidly evolving genes regulate the metabolic pathway, suggesting that what camels do with the nutrients after digestion is a whole different ball game. “It was surprising to me that they had significant difference in the metabolism,” says Kim Worley, a molecular geneticist at Baylor College of Medicine in Houston, Texas. The differences could point to how Bactrians produce and store energy in the desert.

The work shows that camels can withstand massive blood glucose levels owing in part to changes in genes that are linked to type II diabetes in humans. The Bactrians’ rapidly evolving genes include some that regulate insulin signalling pathways, the authors explain. A closer study of how camels respond to insulin may help to unravel how insulin regulation and diabetes work in humans.

The researchers also identified sections of the genome that could begin to explain why Bactrian camels are much better than humans at tolerating high levels of salt in their bloodstreams. In humans, the gene CYP2J controls hypertension, suppressing it leads to high blood pressure. However, camels have multiple copies of the gene, which could keep their blood pressure low even when they consume a lot of salt, suggest the authors of the latest work.