Humans may have made significant evolutionary changes much more recently than previously thought, as little as 3,000 years ago, researchers say.
Scientists from the Beijing Genomics Institute found among Tibetans a set of genes showing they evolved to deal with low oxygen levels just 30 centuries ago, The New York Times reported Monday.
The spread of the new gene is just one instance of recent human evolution and of a specific group changing genetically in response to local conditions, researchers say.
Many scientists once thought humans ceased to evolve in the distant past after people first learned to protect themselves against cold, famine and other harsh agents of natural selection.
But research into human genome sequences around the world has shown increasing evidence of natural selection at work in the last few thousand years, suggesting human evolution is still in progress, the Times said.
earlier related report
New monument unearthed at Stonehenge
Birmingham, England (UPI) Jul 22, 2010 –
A new "henge," or ceremonial circle, has been unearthed at Britain's Stonehenge in what archaeologists are calling the most exciting find there in 50 years.
A circular ditch surrounding a small circle of deep pits archaeologists believe held timber posts was unearthed about a half mile from the famous stone circle at the site, BBC News reported.
"When you see that as an archaeologist, you just looked at it and thought, 'that's a henge monument' — it's a timber equivalent to Stonehenge," Professor Vince Gaffney of the University of Birmingham said.
"This is probably the first major ceremonial monument that has been found in the past 50 years or so," he said.
Why the 4,500-year-old Stonehenge was built will be debated and studies for years, but most experts believe it was a cemetery for 500 years, from the point of its inception, the BBC said.
The current excavations, the first at the site in almost 50 years, began in 2008, assisted by the National Trust and English Heritage.
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