| Genetic genealogy is the application of | | | | order to estimate the probability that they |
| genetics to traditional genealogy. Genetic | | | | share a common ancestor in a genealogical |
| genealogy involves the use of genealogical | | | | time frame and, through the use of a Bayesian |
| DNA testing to determine the level of genetic | | | | model published by Bruce Walsh, to estimate |
| relationship between individuals. | | | | the number generations separating the two |
| | | | individuals from their most recent common |
| The investigation of surnames in genetics can | | | | ancestor. |
| be said to go back to George Darwin, son of | | | | |
| the founder of evolutionary science. In 1875, | | | | Y-DNA research involves short tandem repeat |
| Darwin fils (french "son") used surnames to | | | | (STR) and, sometimes, single nucleotide |
| estimate the frequency of first-cousin | | | | polymorphism (SNP) testing of the |
| marriages and calculated the expected | | | | Y-chromosome. The Y-chromosome is present |
| incidence of marriage between people of the | | | | only in males and reveals information on the |
| same surname (isonymy). He arrived at a | | | | strict paternal line. These tests can provide |
| figure between 2.25% and 4.5% for | | | | insight in the recent (via STRs) and ancient |
| cousin-marriage in the population of Great | | | | (via SNPs) genetic ancestry. A Y-chromosome |
| Britain, with the upper classes being on the | | | | STR test will reveal a haplotype, which |
| high end and the general rural population on | | | | should be similar among all male descendants |
| the low end. Admittedly, this was a pretty | | | | of a male ancestor. SNP tests are used to |
| crude effort by modern scientific standards | | | | assign people to a paternal haplogroup, which |
| but quite innovative for its era. The next | | | | defines a genetic population. |
| stimulus toward using genetics to study | | | | |
| family history had to wait until the 1990s, | | | | mtDNA research involves sequencing the HVR-1 |
| when certain locations on the Y chromosome | | | | region, HVR-2 region or both. A mtDNA test |
| were identified as being useful for tracing | | | | can also be used to assign people to a |
| male-to-male inheritance. | | | | maternal haplogroup. |
| | | | |
| When a Canadian nephrologist of Ashkenazi | | | | Either Y-DNA or mtDNA test results can be |
| parentage attended synagogue one morning, he | | | | compared to the results of others via private |
| noticed that a Sephardic congregant with the | | | | or public DNA databases. |
| same surname as his – Cohen — | | | | |
| seemed to have completely different physical | | | | Biogeographical and ethnic origins |
| features. According to the traditions of | | | | |
| Judaism, Cohens are descended from the same | | | | Additional DNA tests exist for determining |
| male ancestor, the priest Aaron, brother of | | | | biogeographical and ethnic origin, but these |
| Moses. Dr. Skorecki reasoned that if Kohanim | | | | tests have less relevance for traditional |
| (plural of Cohen) were indeed the descendants | | | | genealogy. |
| of only one man, they should have a common | | | | |
| set of genetic markers and should perhaps | | | | See biogeographic ancestry, genealogical DNA |
| preserve some family resemblance to each | | | | test and population genetics (the study of |
| other. | | | | the distribution of and change in allele |
| | | | frequencies). |
| To test that hypothesis, he contacted | | | | |
| Professor Michael Hammer of the University of | | | | Human migration |
| Arizona, a researcher in molecular genetics | | | | |
| and pioneer in Y chromosome research. Their | | | | Genealogical DNA testing methods are also |
| report in the Nature in 1997 sent shock waves | | | | being used on a longer time scale to trace |
| through the worlds of science and religion. A | | | | human migratory patterns and determine, for |
| particular marker pattern (now known as the | | | | example, when the first humans came to North |
| Cohen Modal Haplotype, or CMH) did indeed | | | | America and how they got there. For several |
| appear in 98.5% of Jewish men bearing the | | | | years, a number of researchers and |
| surname Cohen (or a variation thereof such as | | | | laboratories from around the world have been |
| Cone). It was apparently true that knowledge | | | | sampling indigenous populations from around |
| of their priestly calling and descent from | | | | the globe in an effort to map historical |
| the Biblical Aaron had been strictly | | | | human migration patterns. Recently, several |
| preserved for thousands of years. Moreover, | | | | projects have been created that are aimed at |
| the data showed that there were very few | | | | bringing this science to the public. One |
| “non-paternity events." | | | | example is the Genographic Project, which |
| | | | aims to map historical human migration |
| The first to test the new methodology in | | | | patterns by collecting and analyzing DNA |
| general surname research was Bryan Sykes, a | | | | samples from over 100,000 people across five |
| molecular biologist at Oxford University. His | | | | continents. |
| study of the Sykes surname obtained valid | | | | |
| results by looking at only four markers on | | | | Typical customers and interest groups |
| the male chromosome. It pointed the way to | | | | |
| genetics becoming a valuable assistant in the | | | | Male DNA testing customers most often start |
| service of genealogy and history. In 2001, | | | | with a Y chromosome test to determine their |
| Sykes went on to write the popular book The | | | | father's paternal ancestry. Females generally |
| Seven Daughters of Eve. | | | | begin with a mitochondrial test to trace |
| | | | their ancient maternal lineage, which males |
| In the wake of that book's success, and the | | | | often have tested for the same purpose. |
| growing availability and affordability of | | | | |
| genealogical DNA tests, genetic genealogy as | | | | A common consumer goal in purchasing DNA |
| a field began growing rapidly. By 2003, the | | | | testing services is to acquire quantified, |
| field of DNA testing of surnames was declared | | | | ‘scientific’ linkage to a |
| officially to have “arrived†in | | | | specific ancestral group. A compelling |
| an article by Jobling and Tyler-Smith in | | | | example of this motive is found in the |
| Nature Reviews Genetics. The number of firms | | | | expressed desires of some consumers to be |
| offering tests, and the number of consumers | | | | proven to have Viking paternal ancestry. In |
| ordering them, had risen dramatically. | | | | keeping with this marketplace demand, one |
| | | | British DNA testing service, Oxford |
| Another milestone in the acceptance of | | | | Ancestors, offers a Y chromosome test |
| genetic genealogy is the Genographic Project. | | | | purporting to measure whether given males are |
| The Genographic Project is a five-year | | | | of "Viking stock." Those whose DNA falls into |
| research partnership launched by the National | | | | the designated haplogroup are issued Viking |
| Geographic Society and IBM in 2005. Although | | | | Descendant certificates by the testing |
| its goals are primarily anthropological, not | | | | service. The same DNA testing company (Oxford |
| genealogical, the project's sale of over | | | | Ancestors) participated in producing a |
| 150,000 testing kits (as of July 2006) of its | | | | televised documentary, "The Blood of the |
| public participation kits, which test the | | | | Vikings," in conjunction with the BBC, which |
| general public for either twelve STR markers | | | | showed how DNA testing could reveal Viking |
| on the Y chromosome or the HVR1 region of the | | | | ancestry. |
| mtDNA, has helped increase the visibility of | | | | |
| genetic genealogy. | | | | The Rootsweb DNA-Genealogy Internet |
| | | | discussion group has a membership of 750 |
| Annual sales of genetic genealogical tests | | | | subscribers from around the world. Some |
| for all companies, including the laboratories | | | | subscribers have had various DNA tests |
| that support them, are estimated to be in the | | | | performed and are seeking advice and guidance |
| area of $60 million (2006). | | | | in interpreting their results, and the list |
| | | | also includes administrators of DNA projects |
| Uses | | | | that examine surnames (e.g., Stewart, Hurst, |
| | | | Wells, etc.), geographic regionans (e.g., the |
| Paternal and maternal lineages | | | | Shetland Islands, Mexico, Scotland, etc.), or |
| | | | ethnic groups (e.g., the Pennsylvania |
| The two most common types of genetic | | | | Deutsch, African Americans, etc.). The |
| genealogy tests are Y-DNA (paternal line) and | | | | sophistication of subscribers ranges from |
| mtDNA (maternal line) genealogical DNA tests. | | | | expert to novice, and, in some cases, |
| | | | subscribers have been credited with making |
| These tests involve the comparison of certain | | | | useful and novel contributions to knowledge |
| sequences of DNA pairs of individuals in | | | | in the field of genetic genealogy. |