NEWS NATURE|Vol 465|13 May 2010 Ancient DNA set to rewrite human history Discovery that some humans are part-Neanderthal reveals the promise of comparing genomes old and new. The worlds of ancient and modern DNA explor- with new strategies for reducing or detecting ation have collided in spectacular fashion in the contamination by near-identical modern OLIBRARY past few months. Last week saw the publication human DNA. These days, labs such as Pääbo’s T of a long-awaited draft genome of the Neander- and Willerslev’s might piece together a com- PHO thal, an archaic hominin from about 40,000 years plete genome from the degraded scraps of ago1. Just three months earlier, researchers in DNA present in ancient bone, hair or teeth in Denmark reported the genome of a 4,000-year- as little as a month. Researchers from geneti- old Saqqaq Palaeo-Eskimo2 that was plucked cists to fossil specialists can’t wait for more. from the Greenland permafrost and sequenced Some hope to use ancient–modern genome in China using the latest technology. comparisons to chart splits in human popu- As researchers compare these ancient lations and how they might have correlated genomes with the ever-expanding number from with climatic changes. “I call this molecular today’s humans, they expect to gain insights stratigraphy,” says Jeffrey Long, a genetic into human evolution and migration — with anthropologist at the University of New Mexico more discoveries to come as they decipher DNA in Albuquerque. “I then want to use this rela- from other branches of the human evolutionary tive chronology of genetic events to compare to tree. “For the first time, ancient and modern the palaeoclimate of Earth’s biomes.” genetic research is going hand in hand,” says For Willerslev, ancient genomes offer the Eske Willerslev, whose team at the University of opportunity to trace prehistoric migration Copenhagen led the Palaeo-Eskimo sequencing routes. By comparing the ancient Saqqaq project. “It is really a fantastic time.” genome with those of modern human popula- Already, analysis of the Neanderthal genome Neanderthals once bred with Homo sapiens. tions, Willerslev and his team linked it to the has helped to resolve a debate about whether present-day Chukchi people of Siberia, revealing there was interbreeding between Neanderthals for Evolutionary Anthropology in Leipzig, that ancestors of this group trekked from eastern and Homo sapiens: genome comparisons suggest Germany, found that the genomes of non- Siberia to Greenland about 5,500 years ago. “The that the two groups mated an estimated 45,000– African H. sapiens today contain around 1–4% genomes will allow us to test theories about peo- 80,000 years ago in the eastern Mediterranean of sequence inherited from Neanderthals. ples and migrations debated for a century,” says area. The sequencing study, from a consortium The breakthroughs have been driven by Willerslev. “In the next five years, we will see a led by Svante Pääbo of the Max Planck Institute the plummeting cost of sequencing, together whole spectrum of discoveries.” For example, China and Taiwan strengthen academic ties After a year of debate that on graduate or undergraduate finalized the amendments. An explosion in the number of several occasions descended into exchange students. But, thus far, Many scientists see the plan as universities in Taiwan — from 40 fisticuffs, Taiwanese legislators this Taiwanese law has barred them from an opportunity to keep the island to 175 during the past 20 years — week opted for pragmatism over graduate or undergraduate degree internationally competitive. “The along with a declining birth rate nationalism and put the finishing programmes. talent and the hard-working attitude means that there are plenty of touches to amendments that Taiwan’s Chinese Nationalist in general of the mainland students places available for mainlanders: will allow about 2,000 mainland Party government proposed relaxing will be a boost to research,” says Ben about 55,000 by 2015, according to Chinese students to enter Taiwan’s these rules more than a year ago, as Chao, dean of the Earth sciences census figures. And there will be no graduate and undergraduate part of a warming relationship that college at Taiwan’s National Central shortage of applicants, says Cong university programmes every year. has seen increased business and University in Jhongli City. Kuo-Fong Cao at the Levin Institute in New The change, to be finalized this transportation links with mainland Ma, a seismologist at the university, York, who studies China’s science month, will open the door to a large China. But, fearing that both the says that it will also benefit science and technology manpower issues. and much-needed pool of young universities and the workforce on the mainland. Taiwan has a He points out that students will minds for Taiwan’s universities as could be overrun by mainlanders, strong record in earthquake early not suffer the language problems early as this autumn. opposition party members resisted, warning systems, for example, or culture shock that study abroad Taiwan has strong research with some resorting to grappling a and educating mainland students could bring. “Moreover, professors universities but a shortage of speaker to the floor of the legislature could help to establish more at Taiwan’s universities are more students. Many mainlanders already last month in an attempt to block the research collaborations and transfer serious about advising students,” head to Taiwan for postdoctoral motion. On 10 May, violence broke knowledge that could benefit the Cao argues. studies, and some go as short-term out again before a subcommittee whole of China. But the amendments still bar 148 © 2010 Macmillan Publishers Limited. All rights reserved VolNATURE 465|13|Vol May 465 2010|13 May 2010 NEWS the work could reveal whether the first Native development of the occipital bun, a bulge at the Americans included migrants from Europe who back of the skull that is found in Neanderthals crossed the ice-age Atlantic Ocean. and in some modern humans. “We need to look Pääbo and his team had nearly completed and clarify certain characteristics in Neander- the Neanderthal genome by early 2009, about thal morphology with genetics,” he says. four years after the sequencing effort began. Most researchers in the field anticipate But, to carry out their analysis, the researchers that the next ancient human genome will raced to sequence five genomes of people from be completed by Pääbo’s group, from a tiny diverse modern populations in Europe, Asia finger bone found in a cave in the Altai Moun- and Africa. By comparing these “For the first time, tains in southern Siberia. In to the Neanderthal genome, March, the group reported the they found 78 protein-altering ancient and modern mitochondrial DNA sequence sequence changes that seem to genetic research is from this individual3, an have arisen since the divergence going hand in hand.” unknown hominin that, so from Neanderthals several hun- far, does not genetically match dred thousand years ago, plus a handful of either Neanderthals or H. sapiens and may other genomic regions that show signs of pos- represent a new species. The team dated the itive selection in modern humans. These are bone to about 40,000 years ago, but others linked to sperm motility, wound healing, skin say that the sediments around the bone may function, genetic transcription control and be as old as 100,000 years. There is specula- cognitive development. The team also found tion that the bone could be the remains of that only the modern African genomes lacked an older species of Homo, perhaps even of a segments of Neanderthal ancestry, indicating remnant population of Homo heidelbergensis, that interbreeding between the two groups known in Europe from 300,000 to 500,000 probably occurred after humans migrated out years ago, or of Homo erectus, found as early as of Africa. 1.8 million years ago from Africa to Indonesia. That revelation is likely to revive the debate A full sequence may help to resolve this. about whether or not the two groups are sepa- Obtaining the genome of a human ances- rate species, says anthropologist Fred Smith of tor this old was previously unimaginable. Illinois State University in Normal, who has “I honestly believe this new era will change our studied Neanderthals in Europe. Smith thinks view of human evolution,” Willerslev says. ■ that they are a subspecies of H. sapiens. Now Rex Dalton that the genomes can be compared, it will be 1. Green, R. E. et al. Science 328, 710–722 (2010). possible to investigate the genetic roots of some 2. Rasmussen, M. et al. Nature 463, 757–762 (2010). shared features. For instance, he points to the 3. Krause, J. et al. Nature 464, 894–897 (2010). at Peking University in Beijing, NIV. U adds that many mainland students prefer to do graduate L TAIWAN TAIWAN L work at US universities. T A N Andrew Wang, vice- IOL., president of Taiwan’s premier B scientific institute, Academia EVOL. EVOL. Sinica, says that mainlanders D may be wary of returning from OL. AN OL. Taiwan with a freshly minted C . E . T Taiwan’s universities are set to take in Chinese students. diploma bearing the phrase NS I ‘National Taiwan University’ — U/ H the major national universities of Chinese Bioscientists in a rubric that challenges Beijing’s J.-M. J.-M. from accepting Chinese America, a formerly Taiwanese- assertion that Taiwan is part of undergraduates — a big caveat dominated academic China, and not an independent — and withhold Taiwanese networking group (see Nature nation. There is also concern government scholarships from 459, 1044; 2009). Wang says that if places at top universities mainlanders.