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中国人是印第安人、爱斯基摩人、因纽特人的共同祖先?

已有 18460 次阅读 2014-8-29 08:00 |个人分类:期刊论文|系统分类:论文交流| 印第安人, 爱斯基摩人, 因纽特人

在刚刚出版的Science上,丹麦哥本哈根大学研究人员发文称,他们经过基因测序分析,确定了美洲本土的土著美洲人(印第安人)及阿拉斯加、加拿大北部、格陵兰岛(新世界北极地区)的爱斯基摩人和因纽特人都来自跨越白令海峡的西伯利亚人。

最先踏上美洲大陆的是印第安人(24000-14500年前),其次是爱斯基摩人(5000-700年前),随后是因纽特人(1000-700年前)。以往所称的爱斯基摩人是古爱斯基摩人(Palio-Eskimo),而所谓的新爱斯基摩人(Neo-Eskimo)就是因纽特人。

该研究可以确定爱斯基摩人与因纽特人之间有基因交流(通婚),但尚不能确定因纽特人的到来为何让爱斯基摩人消亡。研究人员提到一个传说:爱斯基摩人很高大,但却不堪一击,暗示因纽特人的祖先可能“灭”了爱斯基摩人。

此前发表在PNAS的一篇报道称,古人类染色体及线粒体DNA分析显示,4万年前生活在北京地区的人类与现代亚洲人及美洲人有亲缘关系,难道中国人是西伯利亚人、印第安人、爱斯基摩人、因纽特人的共同祖先?


A relative from the Tianyuan Cave: Humans living 40,000 years ago likely related to many present-day Asians and Native Americans

Date:
January 21, 2013
Source:
Max-Planck-Gesellschaft
Summary:
Ancient DNA has revealed that humans living some 40,000 years ago in the area near Beijing were likely related to many present-day Asians and Native Americans.


The leg of the early modern human from Tianyuan Cave was used for the genetic analysis as well as for carbon dating.
Credit: MPI for Evolutionary Anthropology

Ancient DNA has revealed that humans living some 40,000 years ago in the area near Beijing were likely related to many present-day Asians and Native Americans.

An international team of researchers including Svante Pääbo and Qiaomei Fu of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, sequenced nuclear and mitochondrial DNA that had been extracted from the leg of an early modern human from Tianyuan Cave near Beijing, China. Analyses of this individual's DNA showed that the Tianyuan human shared a common origin with the ancestors of many present-day Asians and Native Americans. In addition, the researchers found that the proportion of Neanderthal and Denisovan-DNA in this early modern human is not higher than in people living in this region nowadays.

Humans with morphology similar to present-day humans appear in the fossil record across Eurasia between 40,000 and 50,000 years ago. The genetic relationships between these early modern humans and present-day human populations had not yet been established. Qiaomei Fu, Matthias Meyer and colleagues of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, extracted nuclear and mitochondrial DNA from a 40,000 year old leg bone found in 2003 at the Tianyuan Cave site located outside Beijing. For their study the researchers were using new techniques that can identify ancient genetic material from an archaeological find even when large quantities of DNA from soil bacteria are present.

The researchers then reconstructed a genetic profile of the leg's owner. "This individual lived during an important evolutionary transition when early modern humans, who shared certain features with earlier forms such as Neanderthals, were replacing Neanderthals and Denisovans, who later became extinct," says Svante Pääbo of the Max Planck Institute for Evolutionary Anthropology, who led the study.

The genetic profile reveals that this early modern human was related to the ancestors of many present-day Asians and Native Americans but had already diverged genetically from the ancestors of present-day Europeans. In addition, the Tianyuan individual did not carry a larger proportion of Neanderthal or Denisovan DNA than present-day people in the region. "More analyses of additional early modern humans across Eurasia will further refine our understanding of when and how modern humans spread across Europe and Asia," says Svante Pääbo.

Parts of the work were carried out in a new laboratory jointly run by the Max Planck Society and the Chinese Academy of Sciences in Beijing.

Story Source:

The above story is based on materials provided by Max-Planck-Gesellschaft. Note: Materials may be edited for content and length.

Journal Reference:

  1. Qiaomei Fu, Matthias Meyer, Xing Gao, Udo Stenzel, Hernán A. Burbano, Janet Kelso, Svante Pääbo. DNA analysis of an early modern human from Tianyuan Cave. PNAS, January 21, 2013



























Prehistoric migrations: DNA study unravels the settlement history of the New World Arctic

Date:
August 28, 2014
Source:
University of Copenhagen
Summary:
A new DNA study unravels the settlement history of the New World Arctic. We know people have lived in the New World Arctic for about 5,000 years. Archaeological evidence clearly shows that a variety of cultures survived the harsh climate in Alaska, Canada and Greenland for thousands of years. Despite this, there are several unanswered questions about these people.


Modern-day dog sledding in Greenland (stock photo). People have lived in the New World Arctic for about 5,000 years. Archaeological evidence clearly shows that a variety of cultures survived the harsh climate in Alaska, Canada and Greenland for thousands of years.
Credit: © Pavel Svoboda / Fotolia

We know people have lived in the New World Arctic for about 5,000 years. Archaeological evidence clearly shows that a variety of cultures survived the harsh climate in Alaska, Canada and Greenland for thousands of years. Despite this, there are several unanswered questions about these people: Where did they come from? Did they come in several waves? When did they arrive? Who are their descendants? And who can call themselves the indigenous peoples of the Arctic? We can now answer some of these questions, thanks to a comprehensive DNA study of current and former inhabitants of Greenland, Arctic Canada, Alaska, the Aleutian Islands and Siberia, conducted by an international team headed by the Centre for GeoGenetics at the Natural History Museum of Denmark, University of Copenhagen.

The results have just been published in the scientific journal Science.

Looking for ancient human remains in northern Greenland.

The North American Arctic was one of the last major regions to be settled by modern humans. This happened when people crossed the Bering Strait from Siberia and wandered into a new world. While the area has long been well researched by archaeologists, little is known of its genetic prehistory. In this study, researchers show that the Paleo-Eskimo, who lived in the Arctic from about 5,000 years ago until about 700 years ago, represented a distinct wave of migration, separate from both Native Americans -- who crossed the Bering Strait much earlier -- and the Inuit, who came from Siberia to the Arctic several thousand years after the Paleo-Eskimos.

"Our genetic studies show that, in reality, the Paleo-Eskimos -- representing one single group -- were the first people in the Arctic, and they survived without outside contact for over 4,000 years," says Lundbeck Foundation Professor Eske Willerslev from Centre for GeoGenetics at the Natural History Museum, University of Copenhagen, who headed the study.

"Our study also shows that the Paleo-Eskimos, after surviving in near-isolation in the harsh Arctic environment for more than 4,000 years, disappeared around 700 years ago -- about the same time when the ancestors of modern-day Inuit spread eastward from Alaska," adds Dr. Maanasa Raghavan of Centre for GeoGenetics and lead author of the article.

Migration pulses into the Americas

Greenlandic Inuit from the 1930s pictured in their traditional boats (umiaq), used for hunting and transportation.

In the archaeological literature, distinctions are drawn between the different cultural units in the Arctic in the period up to the rise of the Thule culture, which replaced all previous Arctic cultures and is the source of today's Inuit in Alaska, Canada and Greenland. The earlier cultures included the Saqqaq or Pre-Dorset and Dorset, comprising the Paleo-Eskimo tradition, with the Dorset being further divided into three phases. All of these had distinctive cultural, lifestyle and subsistence traits as seen in the archaeological record. There were also several periods during which the Arctic was devoid of human settlement. These facts have further raised questions regarding the possibility of several waves of migration from Siberia to Alaska, or perhaps Native Americans migrating north during the first 4,000 years of the Arctic being inhabited.

"Our study shows that, genetically, all of the different Paleo-Eskimo cultures belonged to the same group of people. On the other hand, they are not closely related to the Thule culture, and we see no indication of assimilation between the two groups. We have also ascertained that the Paleo-Eskimos were not descendants of the Native Americans. The genetics reveals that there must have been at least three separate pulses of migration from Siberia into the Americas and the Arctic. First came the ancestors of today's Native Americans, then came the Paleo-Eskimos, and finally the ancestors of today's Inuit," says Eske Willerslev.

Genetics and archaeology

The genetic study underpins some archaeological findings, but not all of them.

It rejects the speculation that the Paleo-Eskimos represented several different peoples, including Native Americans, or that they are direct ancestors of today's Inuit. Also rejected are the theories that the Greenlanders on the east coast or the Canadian Sadlermiut, from Southampton Island in Hudson Bay, who died out as late as 1902-03, were surviving groups of Dorset people. Genetics shows that these groups were Inuit who had developed Dorset-like cultural traits.

The study clearly shows that the diversity of tools and ways of life over time, which in archaeology is often interpreted as a result of migration, does not in fact necessarily reflect influx of new people. The Paleo-Eskimos lived in near-isolation for more than 4,000 years, and during this time their culture developed in such diverse ways that it has led some to interpret them as different peoples.

"Essentially, we have two consecutive waves of genetically distinct groups entering the New World Arctic and giving rise to three discrete cultural units. Through this study, we are able to address the question of cultural versus genetic continuity in one of the most challenging environments that modern humans have successfully settled, and present a comprehensive picture of how the Arctic was peopled," says Dr. Raghavan.

The first inhabitants

The study was unable to establish why the disappearance of the Paleo-Eskimos coincided with the ancestors of the Inuit beginning to colonise the Arctic. There is no doubt that the Inuit ancestors -- who crossed the Bering Strait about 1,000 years ago and reached Greenland around 700 years ago -- were technologically superior.

The Inuit's own myths tell stories of a people before them, which in all likelihood refer to the Paleo-Eskimos. In the myths, they are referred to as the 'Tunit' or 'Sivullirmiut', which means "the first inhabitants." According to these myths they were giants, who were taller and stronger than the Inuit, but easily frightened from their settlements by the newcomers.

Co-author Dr. William Fitzhugh from the Arctic Studies Centre at the Smithsonian Institution says: "Ever since the discovery of a Paleo-Eskimo culture in the North American Arctic in 1925, archaeologists have been mystified by their relationship with the Thule culture ancestors of the modern Inuit. Paleo-Eskimo culture was replaced rapidly around AD 1300-1400, their only traces being references to 'Tunit' in Inuit mythology and adoption of some elements of Dorset technology. This new genomic research settles outstanding issues in Arctic archaeology that have been debated for nearly a century, finding that Paleo-Eskimo and Neo-Eskimo people were genetically distinct, with separate origins in Eastern Siberia, and the Paleo-Eskimo remained isolated in the Eastern Arctic for thousands of years with no significant mixing with each other or with American Indians, Norse, or other Europeans."

Story Source:

The above story is based on materials provided by University of Copenhagen. Note: Materials may be edited for content and length.

Journal Reference:

  1. M. Raghavan, M. DeGiorgio, A. Albrechtsen, I. Moltke, P. Skoglund, T. S. Korneliussen, B. Gronnow, M. Appelt, H. C. Gullov, T. M. Friesen, W. Fitzhugh, H. Malmstrom, S. Rasmussen, J. Olsen, L. Melchior, B. T. Fuller, S. M. Fahrni, T. Stafford, V. Grimes, M. A. P. Renouf, J. Cybulski, N. Lynnerup, M. M. Lahr, K. Britton, R. Knecht, J. Arneborg, M. Metspalu, O. E. Cornejo, A.-S. Malaspinas, Y. Wang, M. Rasmussen, V. Raghavan, T. V. O. Hansen, E. Khusnutdinova, T. Pierre, K. Dneprovsky, C. Andreasen, H. Lange, M. G. Hayes, J. Coltrain, V. A. Spitsyn, A. Gotherstrom, L. Orlando, T. Kivisild, R. Villems, M. H. Crawford, F. C. Nielsen, J. Dissing, J. Heinemeier, M. Meldgaard, C. Bustamante, D. H. O'Rourke, M. Jakobsson, M. T. P. Gilbert, R. Nielsen, E. Willerslev. The genetic prehistory of the New World Arctic. Science, 2014; 345 (6200): 1255832 DOI:10.1126/science.1255832




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