Introduction
Much discourse is emerging from scientific circles detailing the results of genetic testing in relation to human migration patterns. These studies attempt to show the distribution of ethnic genetic codes over certain geographic areas in relation to time. This article attempts to explain some of this research.
Scientists have now identified the human lineages of the world descended from 10 sons of a genetic Adam and 18 daughters of Eve. This ancestral human population lived in Africa and started to split up 144,000 years ago. This time period is when both the mitochondrial and Y chromosome trees first branch out.
You will also notice that the analysis of DNA from many ancient skeletons and mummies (studies mentioned below) is performed on the mitochondrial DNA, or mtDNA. This "ancient" DNA is often degraded and present in very small quantities. mtDNA offers the best chance of isolating DNA from ancient samples because it is small and is present in the cell with many copies.
18 Daughters of a Genetic Eve
Dr. Douglas C. Wallace and his colleagues at the Emory University School of Medicine in Atlanta constructed a world female genetic tree based on mitochondrial DNA. Dr. Wallace found that almost all American Indians have mtDNA that belong to lineages he named A, B, C and D. Europeans belong to lineages H through K and T through X. The split between the two main branches in the European tree suggests that modern humans reached Europe 39,000 to 51,000 years ago, Dr. Wallace calculates, a time that corresponds with the archaeological date of at least 35,000 years ago.
In Asia the ancestral lineage is known as M, with descendant branches E, F and G. In the Americas are lineages A through D. In Africa there is a single main lineage, known as L, which is divided into three branches. L3, the youngest branch, is common in East Africa and is believed to be the source of both the Asian and European lineages.
Dr. Wallace's mitochondrial DNA lineages are "haplogroups" but known as "daughters of Eve," because all of the lineages are branches of the trunk that stems from the mitochondrial Eve.
Dr. Wallace is now exploring the root of the mitochondrial tree. In the March 2000 American Journal of Human Genetics, he and colleagues identify the Vasikela Kung of the northwestern Kalahari desert in southern Africa as the population that lies nearest to the root of the human mtDNA tree. Another population that seems almost equally old is that of the Biaka pygmies of Central Africa.
The 7 European Daughters of Eve
Professor Sykes and Oxford University researchers in England have identified seven ancestral matriarchal groups from which all Europeans appear to be descended. Every European can trace his or her evolutionary history back to the seven ancestral mother groups, also referred to as the Seven European Daughters of Eve. Sykes et al. obtained buccal cells from 6,000 individuals and analyzed the samples using the mitochondrial DNA (mtDNA) analysis. It is known that mtDNA mutates at a very slow rate, such as 1 mutation in every 10,000 years. So they figured that the women would have lived between 8,000 and 45,000 years ago. What is amazing is that all seven of the genetic groups appear to be descended from the Lara clan, one of three clans that still exist today in Africa. This is called the African Eve theory. It was proposed in the late 1980's by Allan Wilson, Mark Stoneking and others. The African Eve theory states that all humans share a common African ancestor.
The Seven European Daughters of Eve matriarchal groups correspond to Dr. Wallace's lineages above, and were given names by Professor Sykes:
Helena: This clan lived in the ice-capped Pyrenees. As the climate warmed, Helena's descendants trekked northward to what is now England, some 12,000 years ago. Members of this group are now present in all European countries.
Jasmine: Her people had a relatively happy life in Syria, where they farmed wheat and raised domestic animals. Jasmine's descendants traveled throughout Europe, spreading their agricultural innovations with them.
Katrine: Members of this group lived in Venice 10,000 years ago. Today most of Katrine's clan lives in the Alps.
Tara: This group settled in Tuscany 17,000 years ago. Descendants ventured across northern Europe and eventually crossed the English Channel.
Ursula: Users of stone tools, Ursula's clan members drifted across all of Europe.
Valda: Originally from Spain, Valda and her immediate descendants lived 17,000 years ago. Later relatives moved into northern Finland and Norway.
Xenia: Her people lived in the Caucasus Mountains 25,000 years ago. Just before the Ice Age, this clan spread across Europe, and even reached the Americas. (As Dr. Wallace discovered, the X pattern is a rare European lineage and is also among the northern Native Americans such as the Ojibwa and Sioux.)
10 Sons of a Genetic Adam
A male genetic tree based on the analyses of the Y chromosome has been constructed by Dr. Peter A. Underhill and Dr. Peter J. Oefner of Stanford University. In March 2000, a colleague published the preliminary findings of this study in a book, Genes, People and Languages, by Dr. Luca Cavalli-Sforza (see the Dr's own study Two Waves below). The tree starts with a single Y chromosomal Adam with 10 principal branches. Of these sons of Adam, the first three (designated I, II and III) are found almost exclusively in Africa. Son III's lineage migrated to Asia and fathered sons IV-X. These sons then spread through the rest of the world. Son IV spread to the Sea of Japan, son V to northern India, and sons VI and IX to the South Caspian.
Other Recent Research
Two Migration Waves out of Africa
This study came out of the University of Padua, Italy, under the direction of Dr. Luca Cavalli-Sforza and was published in the December issue of the journal Nature Genetics. In the study, the mtDNA in the blood of people from India and east Africa was analyzed. The results showed that a common maternal ancestor coming out of Africa existed 50,000 years ago between the people of Ethiopia and the Arabian peninsula, and India. Matches were not found in the Middle Eastern populations. In another earlier study, it was found that an earlier migration occurred, pegged at 100,000 years ago, involving a common maternal ancestor coming out of Africa by a northern route, settling in the Mediterranean and in Greece.
Migration Effect on Languages
There are of course efforts under way to take all of these studies above and to relate them to the formation of languages. Dr. Cavalli-Sforza believes the Y chromosome lineages may be associated with the major language groups of the world. Dr. Joseph Greenberg, a linguist at Stanford University, has proposed three migrations, corresponding to the three language groups of the Americas, known as Amerind, Na-Dene and Eskimo-Aleut.
News Flash
You know all the tests tracing back living people's mtDNA to a most recent common ancestor or matriarchal line? Well, in a December 1999 article in the journal Science, Philip Awadalla of the University of Edinburgh, Scotland basically says that those early assumptions may not be fully true. If not, the rate of mutation for mtDNA, often thought of as 1 mutation every 10,000 years, will have to be recalculated. He says this because there may be some reason to suspect that male and female mtDNA somehow combine. It has been known that male mtDNA in sperm is destroyed by the egg after fertilization. It is anybody's guess how male DNA, mtDNA could be involved with the female mtDNA. More studies will have to be done to replicate this study and to further it.
Neanderthals
In the journal Nature, March 2000, William Goodwin of the University of Glasgow and counterparts in Russia and Sweden state that DNA from the bones of a Neanderthal baby who died 29,000 years ago in Russia's Caucasus Mountains is proof that Neanderthals are not ancestors of modern humans. This study agrees with another Neanderthal study from 1997, where DNA from bones of a Neanderthal found in Feldhofer Cave in Germany were analyzed. What we all should look for now is for specimens where there shows signs of Neanderthals and humans interbreeding. If we take the analyses of the 1997 and 1999 studies and compare with future studies, we may find a significant divergence to support that hypothesis. The 1999 study showed that the baby's mitochondrial DNA differed from that of the other Neanderthal in 3.5 percent of the locations tested. However, as compared to humans, the divergence of the Neanderthal DNA was 7 percent, or double. Because of this, coupled with the expected rate of change, Neanderthals and humans had a common ancestor about 500,000 years ago.
Let us not forget another study in the October 26, 1999 issue of the Proceedings of the National Academy of Sciences. In that study, Neanderthal bones coming out of Vindija cave north of Zagreb, Croatia, indicate that Neanderthals and modern man must have coexisted in central Europe for at least 6,000 years. Probabilities of cohabitation and genetic exchange go up, don't you think?
Cheddar Man, England
This is my favorite, maybe because of the name. He is a 9,000-year-old skeleton who lived in a cave, and who has a distant male relative living right down the street in Cheddar, England. Cheddar Man was a Stone Age hunter-gatherer who lived in southwestern England. Scientists from Oxford University's Institute of Molecular Medicine, led by Dr. Sykes, analyzed mitochondrial DNA extracted from one of Cheddar Man's molar teeth. The results were compared to those of 20 people in the area. Researchers say that it shows that Britons descended from European hunter-gatherers rather than Middle Eastern farmers. I would note that since mtDNA analyses were done, we cannot say that Cheddar Man fathered any children since the mtDNA of Cheddar would have been passed down by his mother. The living relative and Cheddar had a most recent common ancestor 10,000 years ago.
Kennewick Man
Yes, have you heard? As of April 25, 2000, the court is allowing DNA testing of this male skeleton, 9,300 years old, from the state of Washington (not originally, if you know what I mean!). Will the study show that Kennewick Man belongs to one of four identified haplogroups, or genetic groups, that have been identified among American Indians? Ancestor of the American Indians, or European heritage? Ancestor of the Ainu people of Japan? Stay tuned.
Iceman
(See the book Uncovering the Life and Times of a Prehistoric Man Found in an Alpine Glacier, by Brenda Fowler; also The Man in the Ice, by Konrad Spindler (although his conclusions are strange re the Iceman's death.)
Iceman was a body found frozen in the Alps in September 1991. He was taken to Innsbruck University, Forensic Medicine Institute in Innsbruck, Austria. Iceman was found on the Italian side of the Austrian-Italian border, only by a few feet. Anyway, when did Iceman live? The answer is 5,348 to 5,298 years ago! The DNA tests showed that the Iceman's DNA fit with DNA sequences of Europeans. Iceman's DNA matches DNA sequences of individuals living in the _tztal Valley and Alpine regions (Handt 1994:1775). Iceman is now in a museum in Bolzano, Italy.
Ice Maiden
The Ice Maiden was a girl only 12-14 years old who was apparently sacrificed by Inca priests 500 years ago. She was a frozen and well preserved mummy, discovered in September 1995 on Mt. Ampato in the Peruvian Andes by anthropologist Johan Reinhard and Miguel Zarate. Her DNA was analyzed at The Institute for Genomic Research (TIGR) in Rockville, Maryland. Some mtDNA from a heart sample was analyzed using the PCR method and gel electrophoresis. "We conclude from our analysis that the Ice Maiden's mitochondrial DNA HV1 sequence places her precisely in the native American Indian Haplogroup A. Her HV2 DNA sequence represents a new HV2 variant not found in the current mitochondrial DNA sequence databases and is most closely related to the Ngobe people of Panama" (Mike Knapp, TIGR). For an article on Ice Maiden, see the January 1997 issue of National Geographic.
Beringia and Travel to the Americas
Beringia was a land bridge between 12,000 and 13,000 years ago that was evident once glaciers in the area melted and sea levels decreased. Beringia linked up Siberia and what is now Alaska. What is disputed by scientists is what people came over to the America's, when and how. By land? By boat? Paleo-Indians are believed to have used Beringia. Much DNA evidence is pointing to the use of water travel by Asians. There is the study involving the Olmec "celt" inscriptions versus the Chinese Shang writing, which in many cases is very close. We must also remember the concept of independent invention - that humans do independently invent things.
Chinese Migration to Mexico, B.C.
Researchers studied Native Americans from the Navajo, Chamorro and Flathead tribes. They then determined that all three groups possess a unique type of retrovirus gene, JCV, found only in China and Japan (National Academy of Sciences, 1197). Would seem to suggest travel by boat.
Virus Links Andes with Japan
There is a theory that South America was colonized from Asia thousands of years before any Spaniards set foot in South America. DNA from bone marrow of 1,500 year old mummies found in northern Chile was analyzed. The results show that a virus associated with adult T-cell leukemia was prevalent in native Andeans and in a small section of people from southwest Japan. The study also theorizes that the virus may have originated from paleo-Mongoloids who migrated to Japan and South America more than 10,000 years ago. No doubt that this was an mtDNA PCR study (Nature Medicine, 1999).
Irish with Spanish Genetic Influence ?
Y-chromosome variation and Irish origins, E. Hill, M. Jobling, D. Bradley, 23 March 2000 Volume 404 Nature No. 6776
Americans Descended from Australians ?
Americans from European ancestry are traced to one of the daughters of Africa Eve, as found in a study above. A further study examined a 11,500-year-old skull, found in Brazil, which appears to belong to a woman of African or Aboriginal (Australia) descent. This might suggest boat travel.