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Discoverer Jin Changzhu pointed out that the jawbone curved outward, whereas that of the older species of H. erectus had an inward-sloping chin, and modern human chins generally fut out father than the Guangxi specimen's. Such an intermediate chin, he said, suggested interbreeding with H. erectus. 

In the West, paleoanthropologists and geneticists for the most part vehemently deny that any interbreeding between species of man could have taken place before our type emerged as the sole and supreme species favored by evolution. Neandertals, they claim, were replaced by modern humans in Europe and died out without a trace in the genetic record about 30-40,000 years ago. 

"The initial publication makes shaky claims based on preconceptions," scoffed Tim White, a paleoanthropologist at the University of California, Berkeley.

The title of the report is "Signs of Early Homo sapiens in China?" It was written by Richard Stone and published on page 655 of Vol. 326, no. 5953, of Science.

The confrontation reminds many of the battle over Peking Man dated to about 500,000 years old. At first, the Chinese maintained that East Asian people were descendants of Peking Man (and not of Africans or out-of-African humans). Later, they modified their view and held that modern Asians represent a hybridization with Peking Man. Possibly all the "races" or continent-specific forms of modern man are the result of anatomically modern humans interbreeding with more primitive hominids in their part of the world. 

We wonder why Western scientists are in such a huff about the conclusions of Chinese paleontologists since there is solid proof of admixture between modern humans and archaic human groups like Neandertals, Homo erectus and Homo floresiensis (the fossils of "hobbits" discovered in Indonesia in 2004). One instance among many of publications demonstrating this possibility is:  Jeffrey D Wall, "Detecting Ancient Admixture and Estimating Demongraphic Parameters in Multiple Human Populations," Molecular Biology and Evolution, vol. 26, no. 8 (August 2009), pp. 1823-27.

Perhaps the right hand of genetics doesn't know what the left hand of anthropology is doing or saying in this country.

That’s the import of a trio of opinions in this week’s Nature magazine. One of them, “Genetics without Borders,” criticizes a “UK government scheme to establish nationality through DNA testing [as] scientifically flawed, ethically dubious and potentially damaging to science.” The “scheme” is a peer-reviewed program of the UK Border Agency to test whether some 100 asylum-seekers are Somali nationals. The testing uses a combination of SNPs, mitochondrial DNA and Y chromosome, plus other forensic means, to determine whether they are actually Somali or not. (That is, within a high degree of probability, since all inductive conclusions are probabilistic.)  

The editors of Nature fulminate against such methods. Yet these are the tools of the trade used by law enforcement officials and academic geneticists, to say nothing of commercial DNA testing companies. “The idea that genetic variability follows national boundaries is absurd,” they scoff. They are not impressed by the work of fellow scientists John Novembre et al., “Genes Mirror the Geography of Europe,” in Nature 456, 98–101; 2008), saying that the idea that genetic variability follows man-made national boundaries is absurd.” What is absurd is the idea that genetic variability is not molded and delineated by language, culture and historical events – the foundation of national boundaries. It seems to escape the opinion makers that Novembre et al. found that genetic patterns echoed linguistic divisions in Europe. This makes eminent sense in that courtship between most males and females is conducted in the same language. That means within the same nationalistic boundaries. 

Random “mating” of an exogamous nature as envisaged by them is not in the nature of humans. It may be a generalization that can be formed of evolution, which is judged in sweeping retrospective, but it is not true of living people at any given time, in any given land or country. Until the 20th century (and perhaps even today) most people marry someone of the same rather narrowly defined ethnicity as themselves. In fact, until the modern period, an Englishman was most likely to marry a woman whose house was situated only an easy walk away. His horizons --- and thus the eligible gene pool – was limited to a 24 mile square specifically labeled his “country.” 

Geneticists are wont to see human genetics in terms of geologic time, whereas the time depth and landscapes of history are more pertinent. The authors end by urging geneticists, “and indeed all scientists,” to nip the government’s “scheme” in the bud before the public finds out about it and an uprising ensues. This call to action seems to combine scientific cant with a patronizing view of the public. 

Lay persons, and sometimes people outside one’s narrow scientific specialty, just cannot be trusted to get anything quite right, can they?

Another day’s blog will address the other two articles in this week’s Nature, which exhibit similar mandarin attitudes. 

In the last post, we saw that there was discontinuity in the genetic record between medieval and contemporary Tuscans. Contradictions keep popping up whenever geneticists seek to show continuity in human populations. The human facts are not obedient to scientific models. The latest example is an article titled, “Genetic Discontinuity between Local Hunter-Gathers and Central Europe’s First Farmers,” appearing in Science 326/5949:137-40 in October. The authors are B. Bramanti, M. G. Thomas, W. Haak, M. Unterlaender, P. Jores, K. Tambets, I. Antanaitis-Jacobs, M. N. Haidle, R. Jankauskas, C.-J. Kind, F. Lueth, T. Terberger, J. Hiller, S. Matsumura, P. Forster and J. Burger.

After the domestication of animals and crops in the Near East some 11,000 years ago, farming had reached much of central Europe by 7500 years before the present. The extent to which these early European farmers were immigrants or descendants of resident hunter-gatherers who had adopted farming has been widely debated. We compared new mitochondrial DNA (mtDNA) sequences from late European hunter-gatherer skeletons with those from early farmers and from modern Europeans. We find large genetic differences between all three groups that cannot be explained by population continuity alone. Most (82%) of the ancient hunter-gatherers share mtDNA types that are relatively rare in central Europeans today. Together, these analyses provide persuasive evidence that the first farmers were not the descendants of local hunter-gatherers but immigrated into central Europe at the onset of the Neolithic.

It is not often that the august personages who collaborate in the field of population genetics admit to surprise, but this study exhibits a few wavering moments of – I don’t want to say “humility,” but perhaps slight uncertainty. The main intransigence concerns the large presence of mitochondrial haplogroup U in the skeletons analyzed from Central Europe, 13,400 to 2300 BCE. Whereas these types of U are relatively uncommon in Europe today, they were the dominant population then. Germany and surrounding regions were still very much in the Stone Age. Conversely, the Neolithic types H, T and J, which were supposed to be sweeping across the hinterlands and introducing agriculture from the Middle East (along with a characteristic pottery called Linearbandceramik, German for “linear band ceramics,” or LBK) were evidently thin on the ground and held their distance. Nowhere did the twain meet, for “we found no U5 or U4 types in that early farmer sample. Conversely, no N1a or H types were observed in our hunter-gatherer sample, confirming the genetic distinctiveness of these two ancient population samples.” In other words, even the entrenched types of populations living as neighbors, U and N1a, were not mixing with each other. 

Clinging stubbornly to the “classic model of European ancestry components (contrasting hunter-gatherers with early Neolithic farming pioneers),” the authors explain away the facts in simplistic fashion. With breath-taking generalizations, they assume, and then prove, that the “U types in our hunter-gatherer samples [and their not mixing with the other haplogroups]...extend beyond the local scale.” Do they forget that a study they wrote in the same journal four years ago found a predominance of N1a in skeletons in the same region and time? (see Wolfgang Haak, Peter Forster, Barbara Bramanti, Shuichi Matsumura, Guido Brandt, Marc Tänzer, Richard Villems, Colin Renfrew, Detlef Gronenborn, Kurt Werner Alt, and Joachim Burger, “Ancient DNA from the First European Farmers in 7500-Year-Old Neolithic Sites,” Science 11 November 2005: Vol. 310. no. 5750, pp. 1016 – 1018.)

As T.S. Eliot said, “My end is in my beginning.” Thus, the venture ends where it began, with the assumption that there is but one compelling story to be told in Europe for thousands of years after about 6,000 BCE, and that is the triumphal march of agriculturalists across the genetic landscape. With false humility, the authors conclude, “The extent to which modern Europeans are descended from incoming farmers, their hunter-gatherer forerunners, or later incoming groups remains unsolved.” But circular reasoning is circular reasoning even if it does not beget a strong conclusion.

All such studies presume a starlike and gradual diffusion of people. Hence, they expect to see broad patterns of continuity in time and space. Unfortunately, human history is fraught with disjoint as well as discontinuous phenomena. The ant farm models of population genetics cannot begin to comprehend the complexity of the past or do it justice.