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Genetic genealogy'Genetic genealogy' is the application of genetics to traditional genealogy. Genetic genealogy involves the use of genealogical DNA testing to determine the level of genetic relationship between individuals. HistoryThe investigation of surnames in genetics can be said to go back to George Darwin, son of the founder of evolutionary science. In 1875, Darwin fils (sons) used surnames to estimate the frequency of first-cousin marriages and calculated the expected incidence of marriage between people of the same surname (isonymy). He arrived at a figure between 2.25% and 4.5% for cousin-marriage in the population of Great Britain, with the upper classes being on the high end and the general rural population on the low end. Admittedly, this was a pretty crude effort by modern scientific standards, but quite innovative for its era. The next stimulus toward using genetics to study family history had to wait until the 1990s, when certain locations on the Y chromosome were identified as being useful for tracing male-to-male inheritance.It all began when a Canadian nephrologist of Ashkenazi parentage attended synagogue one morning and noticed that a Sephardic congregant with the same surname as his ? Cohen ? seemed to have completely different physical features. According to the traditions of Judaism, Cohens are descended from the same male ancestor, the priest Aaron, brother of Moses, and as such are regarded as the hereditary Jewish priestly caste, called upon first to come forth and read Torah in temple services (alliyah). Dr. Skorecki reasoned that if Kohanim (plural of Cohen) were indeed the descendants of only one man, they should have a common set of genetic markers and should perhaps preserve some family resemblance to each other. To test that hypothesis, he made contact with Professor Michael Hammer of the University of Arizona, a leading researcher in molecular genetics and pioneer in Y chromosome research. Their report in the prestigious British publication Nature in 1997 sent shock waves through the worlds of science and religion. A particular marker (now known as the Cohen Modal Haplotype, or CMH) did indeed appear in 98.5% of Jewish men bearing the surname Cohen (or a variation thereof such as Cone). It was apparently true that knowledge of their priestly calling and descent from the Biblical Aaron had been strictly preserved for thousands of years. Moreover, the data showed that there were very few ?non-paternity events? ? testimony as many pointed out, to the faithfulness of thousands of Mrs. Cohens down through the ages. The first to test the new methodology in general surname research was Bryan Sykes, a molecular biologist at Oxford University. His study of the Sykes surname obtained valid results by looking at only four markers on the male chromosome. It pointed the way to genetics becoming a valuable assistant in the service of genealogy and history. Chronology of commercial companiesIn 2001, Sykes went on to write the popular book The Seven Daughters of Eve and found the home DNA testing firm Oxford Ancestors, a joint venture with Oxford University (since restructured). Just as industrial biotechnology companies sprouted up in the wake of Herbert W. Boyer's creation of Genentech in the 1980s, companies developing and selling genealogical DNA tests have proliferated since then. Already before that, in April of 2000, Bennett Greenspan, a genealogy enthusiast and entrepreneur, had started Family Tree DNA in association with geneticist Michael Hammer of the Arizona Research Laboratories. Hammer is a pioneer in Y chromosome research, and Family Tree DNA today is the leading player. And even earlier, in 1997, Terrence Carmichael, a graduate from Wayne State University School of Medicine, had started up the first direct-to-consumer DNA testing facility, a company called Gene Tree specializing in providing paternity and relationship testing (sold to the Sorenson Companies in 2001).DNA Print was established to commercialize the biogeographical markers developed from the empirical work of Mark Shriver, a biogenetics professor at Pennsylvania State University. Over the same period, Utah philanthropist and medical plastics pioneer James Sorenson privately funded Sorenson Genomics, now a leading high throughput testing laboratory, for-profit Relative Genetics (currently the second ranking company in the industry), and the non-profit Sorenson Molecular Genealogy Foundation, all based in Salt Lake City. Other DNA test companies that sprang to life were:
By 2003 the field of DNA testing of surnames was declared officially to have ?arrived? in an article by Jobling and Tyler-Smith in Nature Reviews Genetics. The first wave of start-ups was joined by Genelex (Seattle, Washington), Geo Gene (Wimbledon, UK, and San Francisco, California) and most recently (2006) by Ethnoancestry (Cypress, California). European consumers are served specifically by Biotix (Potsdam, Germany) and Gen by Gen (Goettingen). Annual sales for all companies, including the laboratories that support them, are estimated to be in the area of $60 million (2006), making genetic genealogy one of the fastest-growing new sectors of technology. UsesPaternal and maternal lineagesThe two most common types of genetic genealogy tests are Y-DNA (paternal line) and mtDNA (maternal line) genealogical DNA tests.These tests involve the comparison of certain sequences of DNA from one individual to that of another to scientifically determine how many generations ago the two individuals shared their most recent common ancestor. These tests allow two individuals to determine with reasonable certainty that they are related within a certain time frame, or with complete certainty that they are not related within a certain time frame. Y-DNA research involves short tandem repeat (STR) testing and mtDNA research involves sequencing the HVR-1 region, HVR-2 region or both. A number of searchable Y-DNA databases are open to the public and available online. Biogeographical and ethnic originsAdditional DNA tests exist for determining biogeographical and ethnic origin, but these test have less relevance for traditional genealogy.See biogeographic ancestry, genealogical DNA test and population genetics (the study of the distribution of and change in allele frequencies). Human migrationMain|Human migration
Genealogical DNA testing methods are also being used on a longer time scale to trace human migratory patterns and determine, for example, when the first humans came to North America and how they got there. For several years, a number of researchers and laboratories from around the world have been sampling indigenous populations from around the globe in an effort to map historical human migration patterns. Recently, several projects have been created that are aimed at bringing this science to the public. One example is the Genographic Project, which tests 12 DNA markers and aims to map historical human migration patterns by collecting and analyzing DNA samples from over 100,000 people across five continents. However, this is only one of several DNA projects. Today, most DNA labs test at least 20 to 63 markers. A comparison of the projects and tests which available to the public will show the differences in features and capabilities of each project. BenefitsGenetic genealogy gives genealogists a means to check or supplement the historical record with information from genetic data. A positive test match with another individual may:
DrawbacksThe main reasons people cite for not wanting to be DNA tested is cost or concerns over privacy issues. However, costs have decreased since the intriduction of genealogical DNA tests. Additionally, at most labs, the privacy and confidentiality of one's genetic markers is controlled by the person being tested. In databases, listing of individuals is sometimes anonymous and identified by a number which may only be known to the individual, or is at the option of the person tested.Finally, Y-DNA and mtDNA testing each only trace a single lineage (one's father's father's father's etc. lineage or one's mother's mother's mother's etc. lineage). At 10 generations back, an individual has 1024 ancestors and a Y-DNA or mtDNA test is only studying one of those 1024 ancestors, as well as their descendants and siblings (same sexed siblings for Y-DNA or all siblings for mtDNA). Acceptance of DNA testingThe pursuit of genetic genealogy would not be possible without the formation of companies like Oxford Ancestors and Family Tree DNA. Traditional genealogists have sometimes plauded and sometimes scotched, the idea of rewriting history, even family history, with genetic evidence. For instance, http://www.geocities.com/ourmelungeons/demarce.html Virginia DeMarce viciously attacked Brent Kennedy's findings about his own family's Turkish and Jewish roots, which were partially based on DNA. Elizabeth C. Hirschman, a professor at Rutgers University, published the first book to use DNA in the wholesale revision of history with The Melungeons : The Last Lost Tribe in AmericaMelungeons'': The Last Lost Tribe in America''">http://www.mupress.org/webpages/books/hirschman.html ''The'' Melungeons'': The Last Lost Tribe in America'', and the latter was followed by When Scotland Was Jewishhttp://www.mcfarlandpub.com/book-2.php?isbn=0-7864-2800-7 ''When Scotland Was Jewish''.
Genealogy has long been the preserve of males of the priviledged classes of society. Thus, the appeal of front runner Family Tree DNA's Y chromosome test lay primarily in its value and convenience to busy male professionals. By the same token, findings documenting the presence and prominence of women and ethnic minorities have not found a warm reception in Internet discussion groups or academia. Perhaps notable exceptions are the two companies African Ancestry, founded by Rick Kittles, Co-Director Molecular Genetics, National Human Genome Research Institute, Howard University, and http://www.dnaconsultants.com DNA Consulting Typical customers and interest groupsDNA customers usually start with a Y chromosome test to determine their father's male ancestry. They then will move on to a mitochondrial test to find out which "daughter of Eve" (that is, ancient female lineage) they represent.Since its inception in October 2000, the Rootsweb http://lists.rootsweb.com/index/other/DNA/GENEALOGY-DNA.html DNA-Genealogy A common consumer goal in purchasing DNA testing services is to acquire quantified, ?scientific? linkage to a specific ancestral group from which one believes (or hopes) s/he descends. A compelling example of this motive is found in the expressed desires of some (consistently male) consumers to be proven to have Viking ancestry. In keeping with this marketplace demand, one British DNA testing service, Oxford Ancestors, offers a Y chromosome test purporting to measure whether or not given males are of "Viking stock." Those whose DNA falls into the designated haplogroup are issued Viking Descendant certificates by the testing service. The same DNA testing company (Oxford Ancestors) participated in producing a televised documentary, "The Blood of the Vikings", in conjunction with the BBC, which showed how DNA testing could reveal Viking ancestry. In the futureThe exciting days of new product development in DNA testing are probably over, although new economies of scale may become realizable with novel haplotyping technologies that go beyond the cumbersome techniques of PCR. There is little expectation that proprietary products such as AncestryByDNA 2.5 and EURO DNA 1.0 will be substantially improved with newer versions. It is doubtful whether it will ever become either technically or economically feasible to test any of the hidden "cross-over" lines of inheritance that supplement the strictly male and strictly-female lines. The current dominant interest in the Y chromosome will probably continue. The field of DNA companies is at present a crowded one and new entrants are not likely, though new marketing approaches are, particularly through value added historical interpretive reports, customized research and widely disseminated catalogues of tests in retail outlets. Far-sighted companies are developing new lines of home medical, genetic screening and autosomal linkage disequilibrium tests to supplement their genealogical products.Some doubt that genetic genealogy will ever achieve professional standing in academia or that DNA companies will gain complete respectability in the eyes of the public. They are, in general, not regulated. Certain states, such as California, do require certification from them as "genetic counselors." http://www.genetree.com GeneTree See alsoMain|List of genetic genealogy topics
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* Category:Population genetics Category:DNA Category:Kinship and descent Category:Genealogy Source: Wikipedia | The above article is available under the GNU FDL. | Edit this article
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