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The area of inland lakes in Tibet has expanded 26 percent in the past 20 years.

The lake area, in the Qinghai-Tibet plateau, has an average altitude of 4,500 meters.

It expanded to 32,000 square kilometers from 26,000 square kilometers 20 years ago.

Before the 1990s, the lakes were shrinking, but after that, they began to expand, thanks to the rapid thawing of glaciers and increased precipitation.

Glaciers in the region have shrunk 15 percent in the past 30 years due to global warming, replenishing the surface water, rivers and lakes.

The expansion will continue in the short term, which will help the cultivation and irrigation of crops as well as rehabilitation of the environment.

But rising lakes have inundated pastures and caused geological disasters, including floods and landslides.

Local officials have called for the authorities to strengthen the monitoring of barrier lakes to prevent disasters.

This is NEWS Plus Special English.

A new study has found that Tibetans living on the "roof of the world" can thank an extinct human relative for providing a gene that helps them adapt to the high altitude.

Past research has concluded that a particular gene helps people live in the thin air of the Tibetan plateau. Now the Tibetan version of that gene has been found in DNA from Denisovans (de-NEE'-soh-vens), a poorly understood human relative more closely related to Neanderthals than modern people.

Denisovans are known only from fossils in a Siberian cave that dating to at least 50,000 years ago. Some of their DNA has also been found in other modern populations, indicating that they interbred with ancient members of today's human race long ago.

But the version of the high-altitude gene shared by Denisovans and Tibetans is found in virtually no other population today.

Researchers in the United States explain that Denisovans or their close relatives introduced the gene variant into the modern human species, but it remained rare until some people started moving into the Tibetan plateau.

At that point, it conferred a survival advantage and so spread through the Tibetan population.

The study shows that as early members of today's human species expanded outside of Africa and encountered new environments, they could call on their genetic legacies from other species. That's easier than waiting for a helpful genetic mutation to arise.

The Tibetan plateau is over 4,000 meters above sea-level. The genetic variant helps survival there by affecting the amount of oxygen the blood can carry when a person is in thin air.

As well as the Tibetans, it is found very occasionally in Han Chinese and also exists in Mongolians and Sherpas, who are also related to Tibetans and may have picked it up relatively recently. The researchers found no trace of it outside East Asia.

You are listening to NEWS Plus Special English. I'm Mark Griffiths in Beijing.

DNA testing is taking a bite out of the Bigfoot legend. After scientists analyzed more than 30 hair samples reportedly left behind by Bigfoot and similar mythical beasts like the Himalayan Yeti, they found all of them came from more mundane creatures like bears, wolves, cows and raccoons.

In 2012, researchers at Oxford University in Britain and the Lausanne Museum of Zoology in Switzerland issued an open call, asking museums, scientists and Bigfoot aficionados to share any samples they thought were from the legendary ape-like creatures.

The study is the first peer-reviewed study of Bigfoot, the Yeti and other "anomalous primates".

The researchers tested 36 hair samples from Bhutan, India, Indonesia, Nepal, Russia and the United States using DNA sequencing. All of them matched DNA from known animals. Most were from bears, but there were also hairs from a Malaysian tapir, horses, porcupine, deer, sheep, and a human.

Although the study didn't find any proof of Bigfoot-related creatures, the research team says that doesn't prove that the creatures don't exist.

The scientists did find two samples from ancient polar bears in the Himalayas, which are not known to live there now. That suggests there could be a new or hybrid bear species out there somewhere.

Scientists also say that proving Bigfoot is real requires significantly more than a mere hair sample. They would want visual or physical proof, like a body part, on top of the DNA evidence.

Some experts say that if Bigfoot exists, there will be a lot more to find than just a few errant hairs.

Stuart Pimm, an ecologist at Duke University in the United States, says that those who believe in the Yeti, Bigfoot and the Loch Ness Monster need basic instruction in sex; and that each Yeti has two parents, four grandparents and so on. He says there should have been herds of Yetis discovered, so where are they hiding?

This is NEWS Plus Special English.