NEWS IN FOCUS embrace new ideas, which might have LINGUISTICS been proposed by others. But it showed that except for the newest scientists, young researchers far outpaced older scientists in citing new ideas in their papers, Pack- Language origin alen and Bhattacharya found. Because the two had no way of measuring the actual age of a researcher, they calculated ‘career ages’ — the number of years after a scien- debate rekindled tist’s first publication. “I really like the way they’re approaching things in terms of text analysis,” says Bruce Eurasian steppe gains ground as Indo-European birthplace. Weinberg, an economist at Ohio State Uni- versity in Columbus, who works with Pack- BY EWEN CALLAWAY languages emerged on the Eurasian steppe alen and Bhattacharya on other projects. some 5,000–6,000 years ago, when the All is not lost for senior scientists, how- rom Icelanders to Sri Lankans, some domestication of horses and invention of ever. Packalen and Bhattacharya also 3 billion people speak the more than wheeled transport would have allowed analysed the career stages of papers’ first 400 languages and dialects that belong herders there to rapidly expand their range. authors (who tend to do the bulk of the Fto the Indo-European family. Two fresh stud- Proponents of the ‘steppe hypothesis’ note research) and last authors (who tend to ies — one of ancient human DNA, the other that linguistic reconstructions of a proto-Indo- be supervisors), and found that the most a newly constructed genealogical ‘tree’ of lan- European tongue include words associated innovative combi- guages — point to the steppes of Ukraine and with wheeled vehicles, which were not nation was an early- “One reading Russia as the origin of this major language invented until long after Middle Eastern farm- career first author of the results family, rekindling a long-standing debate. ers had reached Europe. “Most linguists have and a mid-career is that young Scholars have long recognized an Indo- signed up to the steppe hypothesis,” says Paul last author (see ‘Hot guys are European language group that includes Heggarty, a linguist at the Max Planck Insti- spot’). “One read- innovative Germanic, Slavic and Romance languages as tute for Evolutionary Anthropology in Leipzig, ing of the results is but they also well as classical Sanskrit and other languages Germany. that we quantified need some of the south Asian subcontinent. Yet the ori- One knock against the theory was a lack of something that a lot mentorship.” gins of this family of tongues are mired in compelling evidence for a large-scale migra- of people thought controversy. tion from the Eurasian steppe at this time. was true: that young guys are innovative Some researchers hold that an early Indo- A study of ancient human DNA posted to but they also need some mentorship,” says European language was spread by Middle East- the bioRxiv.org preprint server on 10 February Packalen. ern farmers around 8,000–9,500 years ago (see now plugs that gap (W. Haak et al. http://doi. And Weinberg previously found that ‘Steppe in time’). This ‘Anatolian hypothesis’ org/z9d; 2015). A team led by David Reich, an the age at which scientists make Nobel- is supported by well-documented migrations evolutionary and population geneticist at Har- prizewinning breakthroughs is increasing into Europe, where agriculturalists replaced or vard Medical School in Boston, Massachusetts, (B. F. Jones and B. A. Weinberg Proc. Natl interbred with the existing hunter-gatherers. analysed DNA from the bodies of 94 individ- Acad. Sci USA 108, 18910–18914; 2011). “I In 2012, a team led by evolutionary biologist uals who lived across Europe between 8,000 think we’re learning something about what Quentin Atkinson of the University of Auck- and 3,000 years ago. The data confirmed the these different measures are picking up,” land in New Zealand produced a family tree of arrival of Middle Eastern farmers in Europe Weinberg says. Indo-European tongues that also pointed to an between 8,000 and 7,000 years ago. But they Nonetheless, Paul Ginsparg, a physicist Anatolian origin more than 8,000 years ago. also revealed evidence for a second migration at Cornell University in Ithaca, New York, A competing theory posits that the that began several thousand years later. DNA and the founder of the online repository arXiv.org, says that Packalen and Bhat- tacharya’s findings make sense. “In some STEPPE IN TIME An ancient-DNA study links the Corded Ware culture of northern Europe with the Yamnaya culture of the areas of biomedical research it might take Eurasian steppe. It points to a mass migration northwest that would support the Steppe hypothesis, one a couple of years to learn a new set of ideas of two theories that compete to explain the origins of the Indo-European family of languages. and retool a lab,” he says. “Hence it wouldn’t be surprising if established researchers have trouble finding the time to do so.” HTTP://DOI.ORG/Z9D (2015) Ginsparg also wonders whether ana- Corded Ware lysing the full text of papers might tell a Steppe hypothesis AL. ET Yamnaya 5,000–6,000 years ago different story. It could be that established Herders on the Eurasian steppe researchers incorporate fresh ideas into an expanded their range, propelled W. HAAK Black Sea by the domestication of horses existing methodology and framework, and invention of wheeled transport. and therefore mention them deeper in a paper. Packalen, who published his first paper Anatolian hypothesis in 2010, knows that the findings could be 8,000–9,500 years ago tough for some older scientists to swallow. Farmers migrated out of the Middle East, replacing “I look at these findings and say, ‘No way is or interbreeding with the this going to happen to me’,” he says. “I’m resident hunter-gatherers. going to stay innovative. I’m going to learn new ideas.” ■ 284 | NATURE | VOL 518 | 19 FEBRUARY 2015 | CORRECTED 23 FEBRUARY 2015 © 2015 Macmillan Publishers Limited. All rights reserved recovered from steppe herders called the Yamnaya, who lived in what are now Russia and Ukraine around 5,000 years ago, closely matched that of 4,500-year-old individuals from present-day Germany, who were part of a group known as the Corded Ware cul- WYSS INSTITUTE/HARVARD ture that encompassed most of northern Europe. The similarities suggest “a massive migration into the heartland of Europe from its eastern periphery”, the team writes. Yamnaya ancestry survives in the genomes of modern Europeans, with northerners such as Norwegians, Scots and Lithuanians maintaining the strongest link. The geographical extent of the Yamnaya migration is not clear, but the researchers note that the eastern migrants could have completely replaced existing populations, at least in what is now Germany. It is impos- ‘Organs on chips’, such as this simulated lung, could be used to test bodily responses to toxic chemicals. sible to know the language these migrants spoke, but it is likely to have originated in BIOENGINEERING the steppe homelands of the Yamnaya. “This seems like very striking support for at least part of the traditional steppe model of Indo-European diversification,” Scientists seek says Andrew Garrett, a historical linguist at the University of California, Berkeley, whose own work adds further support. ‘Homo chippiens’ When he and his team re-analysed the data from Atkinson’s 2012 family tree, this time taking into account the approximate Biodefence projects aim to mimic the human body using ages of ancient Indo-European languages, networks of simulated organs. they dated the origin to around 6,000 years ago, in line with the steppe hypothesis (W. Chang, et al. Language; in the press). BY SARA REARDON fluid that flows through the system to mimic Atkinson says, however, that the analy- blood. The devices can be used individually or sis assumes that ancient languages such as ach year, the US government spends connected to other types of organs-on-chips to Latin and Old Irish are direct ancestors of hundreds of millions of dollars stock- approximate a biological system, or — eventu- modern languages, instead of side-branches piling countermeasures for potential ally — perhaps an entire human body. of a common ancestor. This makes it appear Ebiological, chemical and radiological warfare The US Environmental Protection that these languages evolved faster than agents. For ethical reasons, many of these treat- Agency plans to announce next month an they did, he says, and would argue incor- ments have never been tested in humans. Now, US$18-million programme to link ‘livers on rectly for a more-recent common tongue. the US military and civilian science agencies chips’ with chips that simulate fetal membranes, Heggarty points out that Reich’s ancient are supporting the development of the next mammary glands and developing limbs. The DNA study is not the final word on the best thing for tests: miniature human organs ultimate aim is to study how environmental steppe hypothesis either. He suspects that on plastic chips. contaminants such as dioxin and bisphenol A the Yamnaya spoke a language that later “It’s unethical to expose humans to the alter metabolism in those organs once they have developed into Slavic, Germanic and other kind of radiation that you’d see in a disaster been processed by the liver. northern European tongues, but he doubts like Fukushima, but you need to be prepared,” The flexibility afforded by model-organ sys- that the group imported the predecessor says Donald Ingber, a bioengineer at Harvard tems is especially attractive to researchers who of all Indo-European languages: “For me, University’s Wyss Institute in Boston, Massa- are investigating dangerous pathogens, given these data look like the steppe population chusetts.