Hmm, this seems to be a mistake.
Firstly, the study seems to contradict a study done one year before by the very same four Japanese scientists, who concluded a genetic relationship between the ancient people of Linzi and modern Taiwanese Han Chinese:
http://www.pubmedcentral.nih.gov/articlere...i?artid=1377723QUOTE
Molecular Genetic Analysis of Remains of a 2,000-Year-Old Human Population in China and Its Relevance for the Origin of the Modern Japanese Population
Hiroki Oota,1 Naruya Saitou,2 Takayuki Matsushita,3 and Shintaroh Ueda1
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We extracted DNA from the human remains excavated from the Yixi site (2,000 years before the present) in the Shandong peninsula of China and, through PCR amplification, determined nucleotide sequences of their mitochondrial D-loop regions. Nucleotide diversity of the ancient Yixi people was similar to those of modern populations. Modern humans in Asia and the circum-Pacific region are divided into six radiation groups, on the basis of the phylogenetic network constructed by means of 414 mtDNA types from 1,298 individuals. We compared the ancient Yixi people with the modern Asian and the circum-Pacific populations, using two indices: frequency distribution of the radiation groups and genetic distances among populations. Both revealed that the closest genetic relatedness is between the ancient Yixi people and the modern Taiwan Han Chinese.
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A couple of years later, another paper points out a potential methodology flaw in the study:
http://mbe.oxfordjournals.org/cgi/content/full/19/10/1737QUOTE
The Emerging Limbs and Twigs of the East Asian mtDNA Tree
Toomas Kivisild*, Helle-Viivi Tolk*, Jüri Parik*, Yiming Wang , Surinder S. Papiha , Hans-Jürgen Bandelt and Richard Villems*
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Comparing just short stretches of HVS-I sequences could therefore easily create the impression of specific European and East Asian mtDNA affinities, e.g., as asserted by figure 3 in Wang et al. (2000) .
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Finally, a year later, another paper was published refuting it outright:
http://mbe.oxfordjournals.org/cgi/content/full/20/2/214QUOTE
Reconstructing the Evolutionary History of China: A Caveat About Inferences Drawn from Ancient DNA
Yong-Gang Yao*, , Qing-Peng Kong*, , Xiao-Yong Man , Hans-Jürgen Bandelt and Ya-Ping Zhang*,||,
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The decipherment of the meager information provided by short fragments of ancient mitochondrial DNA (mtDNA) is notoriously difficult but is regarded as a most promising way toward reconstructing the past from the genetic perspective. By haplogroup-specific hypervariable segment (HVS) motif search and matching or near-matching with available modern data sets, most of the ancient mtDNAs can be tentatively assigned to haplogroups, which are often subcontinent specific. Further typing for mtDNA haplogroup-diagnostic coding region polymorphisms, however, is indispensable for establishing the geographic/genetic affinities of ancient samples with less ambiguity. In the present study, we sequenced a fragment ( 982 bp) of the mtDNA control region in 76 Han individuals from Taian, Shandong, China, and we combined these data with previously reported samples from Zibo and Qingdao, Shandong. The reanalysis of two previously published ancient mtDNA population data sets from Linzi (same province) then indicates that the ancient populations had features in common with the modern populations from south China rather than any specific affinity to the European mtDNA pool.
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And from what I learnt in Bio-Informatics, this problem they point out with sequence length appears to make sense.