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Two studies led by scientists from the University of Pennsylvaniaand National Geographic's Genographic Project reveal newinformation about the migration patterns of the first humans tosettle the Americas. The studies identify the historicalrelationships among various groups of Native American and FirstNations peoples and present the first clear evidence of the geneticimpact of the groups' cultural practices. For many of these populations, this is the first time theirgenetics have been analyzed on a population scale. One study,published in the American Journal of Physical Anthropology, focuseson the Haida and Tlingit communities of southeastern Alaska. Theother study, published in the Proceedings of the National Academyof Sciences, considers the genetic histories of three groups thatlive in the Northwest Territories of Canada. Establishing shared markers in the DNA of people living in thecircumarctic region, the team of scientists uncovered evidence ofinteractions among the tribes during the last several thousandyears. The researchers used these clues to determine how humansmigrated to and settled in North America as long as 20,000 yearsago, after crossing the land bridge from today's Russia, an areaknown as Beringia. Penn houses the Genographic Project's North American researchcenter. "These studies inform our understanding of the initial peoplingprocess in the Americas, what happened after people moved throughand who remained behind in Beringia," said author Theodore Schurr,an associate professor in Penn's Department of Anthropology and theGenographic Project principal investigator for North America. Both papers also confirm theories that linguists had posited, basedon analyses of spoken languages, about population divisions amongcircumarctic populations. Schurr contributed to both papers, along with Penn colleaguesMatthew Dulik, Amanda Owings, Jill Gaieski and Miguel Vilar. The first paper focused on the Haida and Tlingit tribes, which havesimilar material cultures. "They share potlatch, or rituals of feasting, totemic motifs and atype of social organization that is based on matrilineal clans andmoieties," Schurr said. Using cheek-swab DNA samples, the analyses confirmed that the twotribes - although they possessed some similarities in theirmitochondrial DNA makeup - were quite distinct from one another.Comparing the DNA from the Tlingit and Haida with samples fromother circumarctic groups further suggested that the Haida had beenrelatively isolated for a significant period of time. Thisisolation had already been suspected by linguists, who havequestioned whether the Haida language belonged in the Na-Denelanguage family, which encompasses Tlingit, Eyak and Athapaskanlanguages. In the clan system of Haida and Tlingit peoples, children inheritthe clan status - and territory - of their mothers. Each clan isdivided in two moieties, or social groups, for example the Eagleand the Raven in the Tlingit tribe. Traditionally, a person fromthe Raven clan married someone from the Eagle clan and vice versa. "Part of what we were interested in testing was whether we couldsee clear genetic evidence of that social practice in thesegroups," Schurr said. "In fact, we could, demonstrating theimportance of culture in molding human genetic diversity." The other paper expands this view of circumarctic peoples toclosely consider the genetic histories of three groups that live inthe Northwest Territories: the Inuvialuit, the Gwich'in and theTlicho. The Inuivialuit language belongs to the Eskimo-Aleutlanguage family, while the Gwich'in and Tlicho speak languagesbelonging to the Na-Dene family and the Athapaskan subgroup. In this study, the researchers analyzed 100 individual mutationsand 19 short stretches of DNA from all individuals sampled,obtaining the highest-resolution Y chromosome data ever from thesegroups. The team's results indicate several new genetic markers that definepreviously unknown branches of the family tree of circumarcticgroups. One marker, found in the Inuvialuit but not the other twogroups, suggests that this group arose from an Arctic migrationevent somewhere between 4,000 and 8,000 years ago, separate fromthe migration that gave rise to many of the speakers of the Na-Denelanguage group. "If we're correct, [this lineage] was present across the entireArctic and in Beringia," Schurr said. "This means it traces aseparate expansion of Eskimo-Aleut-speaking peoples across thisregion." Many of the native groups who have participated in both studies arealso enthusiastic collaborators, Schurr said. "What we find fits very nicely with their own reckoning of ancestryand descent and with their other historical records. We've gotten alot of support from these communities." "Perhaps the most extraordinary finding to come out of these twostudies is the way the traditional stories and the linguisticpatterns correlate with the genetic data," Spencer Wells,Genographic Project director and National GeographicExplorer-in-Residence, said. "Genetics complements ourunderstanding of history but doesn't replace other components ofgroup identity." Additional contributors to the American Journal of PhysicalAnthropology paper are Sergey Zhadanov of Penn, Judy Ramos of theYakutat Tlingit Tribe, Mary Beth Moss of the Huna IndianAssociation, Francis Natkong of the Hydaburg CooperativeAssociation and the Genographic Consortium. For the Proceedings of the National Academy of Sciences paper, thePenn team worked with Alestine Andre, Ingrid Kritsch, SharonSnowshoe and Ruth Wright of the Gwich'in Social and CulturalInstitute; Crystal Lennie of the Inuvialuit Regional Corporation;Mary Adele Mackenzie, James Martin and Nancy Gibson of the TlichoCommunity Services Authority; Thomas Andrews of the Prince of WalesNorthern Heritage Center; and the Genographic Consortium. Supportfor both studies was provided by the National Geographic Society,IBM, the Waitt Family Foundation and the University ofPennsylvania. I am an expert from laser-stage-light.com, while we provides the quality product, such as China Led Par Can Lights , China Mini Laser Stage Lighting, Mini Laser Stage Lighting,and more.
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