Human ancestor persisted thru Ice Age

Gene editing in Science mag’s breakthrough of 2015

MIAMI, Dec 18, (AFP): After years of studying a mysterious thigh bone from a cave in China, scientists said Thursday they believe it represents an ancient species of human that persisted much longer than previously thought.

The 14,000-year-old bone was uncovered in 1989 in Maludong, known as the Red Deer Cave. The trove of fossils it was initially found with went unstudied until 2012.

The partial femur, though relatively young in age, looks like the bones of far older species like Homo habilis and early Homo erectus that lived more than 1.5 million years ago, said the study in PLOS ONE.

“Its young age suggests the possibility that primitive-looking humans could have survived until very late in our evolution, but we need to careful as it is just one bone,” said co-author professor Ji Xueping from the Yunnan Institute of Cultural Relics and Archaeology in China.

Until now, scientists believed that the only pre-modern humans who survived in what is now Europe and Asia were Neanderthals and Denisovans, both of which disappeared some 40,000 years ago.

Survived

They are believed to have vanished soon after modern humans entered the region, but the new bone suggests another primitive human could have survived far longer, perhaps until the end of the last Ice Age.

“The new find hints at the possibility a pre-modern species may have overlapped in time with modern humans on mainland East Asia, but the case needs to be built up slowly with more bone discoveries,” said co-author Darren Curnoe from the University of New South Wales.

The thigh bone is small, with a thin shaft much like the bones of Homo habilis, which lived 1.5-2.8 million years ago.

The individual would have weighed only about 110 pounds (50 kilograms), which was quite small for pre-modern and Ice Age human standards.

When researchers first announced their discovery of bones in the Red Deer Cave in 2012, describing them as containing an unusual mix of modern and primitive features such as a jutting jaw, broad nose and prominent brow ridges, they were greeted with skepticism by some scientists.

The findings stoked debate over whether or not they represented a new evolutionary line.

“The new discovery once again points towards at least some of the bones from Maludong representing a mysterious pre-modern species,” the research team said in a statement.

However, more work needs to be done before scientists can declare a new species of human has been found.

For now, researchers believe there may have been a more different kinds of human living until very recently in southwest China than previously thought.

“The unique environment and climate of southwest China resulting from the uplift of the Tibetan Pla- teau may have provided a refuge for human diversity, perhaps with premodern groups surviving very late,” Ji said.

“The riddle of the Red Deer Cave people gets even more challenging now,” added Curnoe.

“Just who were these mysterious Stone Age people? Why did they survive so late? And why only in tropical southwest China?”

A gene-editing technique known as CRISPR was named Thursday by the influential US journal Science as 2015’s breakthrough of the year, due to its potential to revolutionize health and medicine.

The method has stirred controversy, particularly after Chinese researchers earlier this year announced they had deliberately edited the DNA of nonviable human embryos from a fertility clinic.

Concerns over such research -and the prospect of altering humans to promote certain, desirable traits -- recently prompted global scientists to urge researchers to steer clear of interfering with embryos destined for pregnancy, citing the risks of introducing permanent changes into the population.

But many are excited about the “superior ability of CRISPR to deliver a gene to the right spot compared to its genome editing competitors -- as well as the technique’s low cost and ease of use,” said the journal Science.

“Clinical researchers are already applying it to create tissue-based treatments for cancer and other dis-

eases,” wrote managing news editor

“CRISPR may also revive the moribund concept of transplanting animal organs into people.”

Thousands of labs, high school students and scientists have already begun exploiting the three-year old technique, he said.

“It’s only slightly hyperbolic to say that if scientists can dream of a genetic manipulation, CRISPR can now make it happen,” said Travis.

The technique, first announced in 2012, experienced a “massive growth spurt last year,” Travis said, describing it as a “molecular marvel.”

editor-in-chief of the Science family of journals, said in an accompanying editorial that “in two years’ time CRISPR will have brought to many diverse fields in biology the enduring level of excitement and optimism that immunotherapy has brought to cancer patients.”

Immunotherapy, a host of techniques which harness the body’s immune cells to fight cancer, was named Science’s breakthrough of 2013.

But the lay public was less enthusiastic about CRISPR, according to online visitors who voted on the top 10 picks of the year on Science’s website.

To 35 percent of voters, the flyby of Pluto by an unmanned NASA probe called New Horizons was the top breakthrough of the year, offering views in unprecedented detail of the distant dwarf planet.