Human history has involved globalization for thousands of years. The peopling of this planet has been called the first great historical act of our species. We all have the same original ancestors. Our first homeland was Africa. Our species has 'globalized" the planet by migration and colonization. (Click here for more information by linking to the Mapping Globalization website)
This segment of the project focuses on the nature and effects of the migration of human beings from Asia across the Pacific Ocean. This process is still taking place. For the most part, the migrations have been from west to east, from the Asian mainland into and across the Pacific. There have also been migrations from the south to the north and vice versa. And there has been some "back" migration to Asia from the Americas.
The Peopling of the Western Hemisphere: The First Americans were Migrants from Asia
Although today there is general agreement among most experts that the First Americans came from Asia, these experts provide competing theories about the timing and the routes associated with human migration to and colonization of the Americas. The most prominent theory about the peopling of the Americas has been the so-called "Bering Land Bridge Theory" of migration and colonization. According to this theory, the first humans to migrate from Asia to the Americas crossed over a land bridge (Beringia) in what is now the Bering Sea during the last ice age, and their descendents then migrated into North America through a gap between the Laurentian and Cordilleran glacial ice sheets.
The archaeological discoveries at sites in Folsom and Clovis, New Mexico in the twentieth century led most archaeologists to believe humans were relatively recent post-glacial migrants to the Western Hemisphere. The remains at the Folsom site were dated to between 10,000 - 11,000 BP (years Before the Present), and the remains in a cave near Clovis, New Mexico were dated to between 12,000 - 12,500 BP. Based on the dates of the human remains at these sites, it was estimated that the original migration from Asia across the land bridge probably occurred around 14,000 BP.
Since the earliest human settlements in the Americas were considered to share the same so called Clovis culture, most experts in the field before the 1990s believed not only that these Clovis settlers (or their immediate ancestors) were the first Americans, but also that they migrated across the Bering Land Bridge (Beringia) from Northeast Asia to Alaska during the last ice age and then migrated southward through an ice-free corridor into the continental interior of North America. From there they were thought to have rapidly peopled North and South America in the space of only 1,000 years or less. However, the subsequent discovery of human remains at older, so-called Pre-Clovis sites in both North and South America has called into question if not seriously undermined the "Clovis-First" and Bering Land Bridge theories.
A competing theory called the "Coastal Migration Theory" contends that the first Americans migrated from Northwest Asia along the northern Pacific coastline of North America in either rafts or some kind of boats. As they migrated southward, the adherents of this theory posit they could have stopped in ice-free refuges along the way. According to this theory, these coastal migrants eventually moved inland as the glacial ice sheet melted and opened up access routes to the continental interior of North America.
Although the Beringian theory still remains popular, it has serious flaws. For example, there is some evidence that suggests an ice-free corridor didn’t open up through the glacial ice sheets until about 11,000 years ago, and many Pre-Clovis sites are older than that. These sites have been found not only in North America (e.g., on Santa Rosa Island, California) but also in South America (e.g., at Monte Verde, Chile). This evidence makes the coastal route of migration more plausible, especially since there may have been ice-free havens along the northern coastline of North America that were accessible by boat as early as 16,000 years ago. Research by scientists like Canadian archaeologist Daryl Fedje and University of Colorado anthropologist E. James Dixon have revealed humans were exploiting coastal resources by the late Clovis period and possibly earlier along the Canadian and Alaskan coasts.
The Bering Land Bridge and Clovis First Theory posits the First Americans spread from the continental interior of North America down the river valleys until they reached the Pacific and Atlantic coasts, where they then adapted to the marine environment. However, researchers like Roberta Hall and Loren Davis find this theory to be lacking in terms of its explanation of the early Pacific Coast human settlements they have researched. They argue that continental migration was more likely in the opposite direction, with first coastal migrants landing at the mouths of rivers along the Pacific coastline and then working their way eastward into the interior.(Click here to see a copy of "Late-Pleistocene Occupations on the Oregon Coast" by Loren Davis and Roberta Hall, Oregon State University, pages 10-12, MT 22, January 2007)
"There is no obvious restriction to coastal migration", according to Davis, who argues: "We know people had to have used boats to get to remote places in the Pacific Rim, like Australia, so few people would claim that boats are out of the question here". Moreover, she points out: "It may have been easier to go south along the coast, because it is not as necessary to master the different environments the way you have to when following an interior route. The environments on a coastal route are very similar, with only the species changing as you go south".
The following quote has been taken from the website on the video documentary "Coming Into America" produced by the U.S. Public Broadcasting System (PBS). It was written by Maggie Villiger on July 20, 2004.
"The archaeologists in "Coming Into America" mostly rely on artifacts like tools to help piece together the history of the first Americans. But in recent years, scientists have begun turning to genetic evidence as they trace the earliest human migrations around the globe."
The predominant theory is that modern humans evolved in Africa and then migrated through the Middle East to Europe and Asia, beginning some time between 40,000 and 60,000 years ago. What was the route for early humans into the Americas? Scientists compare the DNA of indigenous people in the New World with that of people in Europe and Asia, looking for similarities. The more alike two people's DNA, the more closely related they are - it's as if tiny maps of our ancient origins are hidden within our cells. Anthropologists are using genetics to figure out where some of the first Americans came from, and when."
(Click on map to enlarge)
For example, a study of over 600 examples of mitochondrial DNA from 20 different American and 26 Asian populations has provided a new perspective on how the Americas were peopled. The results of the genetic research on which this report is based suggest there was much more genetic diversity in the founding population of humans that came across the Bering Land Bridge than previously thought. This report “Beringian Standstill and Spread of Native American Founders,” which is published online in the journal PLoS One, not only provides a revised phylogenetic map of the ancestral population but also suggests the first migrants from Asia stayed about 15,000 years in Beringia before moving south.
The authors of this report also claim their research shows the DNA Haplotypes of the founding migrants are uniformly distributed across both North and South America, and they do not show a nested structure from north to south. They conclude therefore that after a rather lengthy initial Beringian standstill, the migration south was very rapid and did not take the form of a gradual diffusion. They claim their research also indicates there was back and forth migrations between Northeast Asia and North America as well as a relatively recent two-way gene flow between Siberia and the Artic region of North America. For more information, click here to see "Tamm E, Kivisild T, Reidla M, Metspalu M, Smith DG, et al. (2007) "Beringian Standstill and Spread of Native American Founders. PLoS ONE 2(9): e829.
The colors of the arrows in this map correspond to the approximate timing of migrations from Asia into North America and are decoded in the colored time-bar. According to this study, the initial migration into Berinigia (represented by the red arrow) was followed by a lengthy standstill after which the early ancestors of contemporary Native Americans spread swiftly (see darker orange arrows) throughout the Americas while some of the Beringian maternal lineages–-such as those with haplotype C1a (light orange arrow)--migrated "back" to Northeast Asia. A more recent genetic exchange resulting from the back-migration of people with haplotype A2a (green arrow) into Siberia as well as the migration of people with the haplotype D2a into North America suggest the initial peopling of the Americas (red arrow) was followed by the subsequent arrival of another migration wave (green D2a arrow) from Siberia.
Genographic Project on the Migratory History of Humanity
An international team of leading genetic researchers sponsored by the National Geographic Society is using cutting edge genetic and computer technologies to gather DNA from indigenous peoples around the world. They are using this genetic data to determine the genetic ancestory of both the aboriginal peoples of the world and the migratory history of humanity. The map below depicts the project's findings so far on the migratory history of our ancestors.
The researchers assocaited with this "Genographic Project" have collected DNA data on the genetic ancestry of the indigenous peoples of all the continents, and they are combining this type of genetic data with existing information from archaeology, linguistics, and history. Through combining the genetic data with these other types of information, the researchers involved seek to piece together how the human race populated the planet, including the number, timing and routes of humanity's prehistoric migrations.
(Click on map to enlarge it)
Note that this map, which is based on the genetic research carried out by the Genographic Project, indicates there is genetic evidence of several transpacific waves of migration from Asia into the Americas over a period of some 30,000 years. Whether these waves of migration were by land, sea or both can not be determined definitively by the Genographic Project's genetic data.
The genomes of dozens of population groups have been analyzed, and in June 2009, an analysis of DNA sequence variations in the genome data from the International HapMap Project (Phase II) and CEPH Human Genome Diversity Panel samples was published. This study of 53 populations revealed that they fell into just three genetic groups: (1) Africans, (2) Eurasians (indigenous peoples of Europe, the Middle East, and Southwest Asia), and (3) East Asians, which includes the aboriginal peoples of East Asia, Japan, Southeast Asia, the Americas, and Oceania. (Click here for more information on this study.)
The researchers involved in this study concluded that most ethnic group differences were the result of "genetic drift" (click here to see Wikipedia.org on genetic drift) rather than natural selection. They also found that contemporary African populations have greater genetic diversity than the other two genetic groups, and contemporary Eurasians have more genetic variation than modern East Asians. They attributed the distribution of genetic variations more to migrations and gene flow between populations -- historical relations between groups -- than natural selection.
As stated in the PBS Series entitled Coming into America:
Surprising as it may seem, today many people still live in the same regions as their very distant forefathers. Genetic archaeologists bank on this when they assume individuals can be taken to represent a particular local group. In our contemporary world of high-speed travel and far-flung families, the long history of human migrations continues, at an ever-increasing pace. Future mtDNA and Y chromosome hunters will have their work cut out for them if they try to retrace the steps of today's migrants."
Click here to link to this segment of the program for a good synthesis of the various opposing theories, the existing evidence and the arguments in favor and opposing these theories (continuously updated by Wikipedia.org)
For more information on the peopling of the Americas:
Click here to read "Early humans followed the coast" by Paul Rincon, Science reporter, BBC News, 5 October 2006.
See also: "Seafaring clue" to first Americans by Paul Rincon, Online science staff, BBC News, 26 February, 2004
There is an informative US Public Broadcasting System NOVA program from February 2007 on "America's Stone Age Explorers." The PBS website for this program includes resources on the topics addressed in the program, click here to go to the website.
The Peopling of the Pacific Islands and Polynesian Migrations:
The following maps and information depict the possible migration routes of the Austronesian and Polynesian peoples across the Pacific Ocean. (Click on these pictures to enlarge them)
Chinese Transpacific Migrations
Waves of migration from China into and across the Pacific have taken place throughout China's history. The most recent emigration of Chinese, known as the Chinese Diaspora, occurred between the 19th and mid twentieth centuries. It was caused by war, starvation, European interventions and political instability in China. Most of the migrants in this diaspora were illiterate and poorly educated peasants or manual laborers. They were often called “coolies” (Chinese: 苦力, translation: hard labor). They left China to work in the Americas, Australia, Southeast Asia and other part of the world. For a chronology and basic information on the history of migrations from China, click here: Chinese Migration
Migrations over the last 500 years
Net migration is the difference between immigration and emigration. A positive number implies that more people are immigrating than emigrating. The global net migration patterns in recent years reveal that North America and Western Europe remain the most important immigration destinations. The Middle East, particularly the United Arab Emirates, has also been a destination. The net providers of immigrants remain Mexico, India, China, the Philippines and Indonesia, a pattern that has continued over the last two decades. (Source: The UNEP Environmental Data Explorer, as compiled from World Population Prospects, the 2010 Revision (WPP2010), United Nations Population Division. United Nations Environment Programme)
Links to Online Sources of Information on Transpacific Migrations:
"How and When Did People First Come to North America?" by E. James Dixon, Athena Review: Vol.3, no.2 (2002): Peopling of the Americas issue.
"The Gault Site, Texas, and Clovis Research" Michael Collins, Athena Review: Vol.3, no.2 (2002): Peopling of the Americas issue.
New book on Peopling of the Americas, Currents, Canoes, and DNA Barbara Bennett Peterson (University of Hawaii)
R. Gerard Ward, "A note on population movements in the Cook Islands," Journal of the Polynesian Society, Volume 70 1961, Volume 70, No. 1. pp. 1-10
Website on Polynesian Pathways by Peter Marsh ( See sections on GENETICS REWRITES PACIFIC PREHISTORY, CANADIAN CONNECTION and PERUVIAN CONNECTION)
Click here to see video overview (8 minutes) of The Genographic Project at the website of the National Geographic Genographic Project.
Did you ever wonder about your most ancient ancestors? The Genographic Project will introduce you to them, and explain the genetic journeys associated with your personal lineage over tens of thousands of years. Click here to link to the webpage of the Genographic Project where you can learn how to participate in the project and discover your deep ancestry by purchasing a DNA sample kit.
To see an example of the results of one person's DNA sample analysis who participated in the Genographic Project, click here.
The Seven Daughters of Eve (2001, ISBN 0-393-02018-5) by Bryan Sykes presents the theory of Human mitochondrial genetics for a general audience. Sykes explains the principles of genetics and human evolution, mitochondrial genetics, and his analyses of ancient DNA to genetically link modern humans to prehistoric ancestors. He traces back human migrations, discusses the out of Africa theory and refutes Heyerdahl's theory of the Peruvian origin of the Polynesians. He also describes the use of mitochondrial DNA in assessing the genetic makeup of modern Europe. The title of this book comes from one of the principal achievements of mitochondrial genetics, which is the classification of all modern Europeans into 7 mitochondrial haplogroups. Each haplogroup is defined by set of characteristic mutations on the mitochondrial genome, and can be traced along a person's maternal line to a specific prehistoric woman. Click here to read excerpts from The Seven Daughters of Eve.
Click here for link to The Simplified Haplogroup Locale Chart, April 2008. The alphabetical designations/names of Y-DNA and mitochondrial (mtDNA) haplogroups were assigned independently of one another by different researchers* . This is often confusing to newcomers who think, for example, that a B Y-DNA haplogroup and a B mtDNA haplogroup refer to the same locale and/or time frame. However, this is not the case - as can be seen in this very simplified locale chart. This is a locale chart – not a migration chart.
Click here for link to the Y-DNA Haplogroup Tree 2011 Version: 6.48, Date: 27 June 2011 at the website of the ISOGG (International Society of Genetic Genealogy), which states that it is not affiliated with any registered, trademarked, and/or copyrighted names of companies, websites and organizations. This Y-DNA Haplogroup Tree is for informational purposes only, and does not represent an endorsement by the ISOGG. Because of continuing research, the structure of the Y-DNA Haplogroup Tree changes and ISOGG does its best to keep the tree updated with the latest developments in the field. The viewer may observe other versions of the tree on the Web.