Genetic genealogy

Genetic genealogy is the use of DNA testing in combination with traditional genealogy and traditional genealogical and historical records to infer relationships between individuals. Genetic genealogy involves the use of genealogical DNA testing to determine the level and type of the genetic relationship between individuals. This application of genetics became popular with family historians in the first decade of the 21st century, as tests became affordable. The tests have been promoted by amateur groups, such as surname study groups, or regional genealogical groups, as well as research projects such as the genographic project. As of 2013 hundreds of thousands of people had been tested. As this field has developed, the aims of practitioners broadened, with many seeking knowledge of their ancestry beyond the recent centuries for which traditional pedigrees can be constructed.

History

George Darwin was the first to estimate the frequency of first-cousin marriages

The investigation of surnames in genetics can be said to go back to George Darwin, a son of Charles Darwin. In 1875, George Darwin 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, higher among the upper classes and lower among the general rural population.^[1]

Surname studies

One famous study examined the lineage of descendants of Thomas Jefferson’s paternal line and male lineage descendants of the freed slave, Sally Hemmings.^[2]

Bryan Sykes, a molecular biologist at Oxford University tested the new methodology in general surname research. His study of the Sykes surname obtained results by looking at four STR markers on the male chromosome. It pointed the way to genetics becoming a valuable assistant in the service of genealogy and history.^[3]

Direct to consumer paternity testing

The first company to provide direct-to-consumer genetic DNA testing was the now defunct GeneTree. However, it did not offer multi-generational genealogy tests. In fall 2001, GeneTree sold its assets to Salt Lake City-based Sorenson Molecular Genealogy Foundation (SMGF) which originated in 1999.^[4] While in operation, SMGF provided free Y-Chromosome and mitochondrial DNA tests to thousands.^[5] Later, GeneTree returned to genetic testing for genealogy in conjunction with the Sorenson parent company and eventually was part of the assets acquired in the Ancestry.com buyout of SMGF.^[6]

The genetic genealogy revolution

In 2000, Family Tree DNA, founded by Bennett Greenspan and Max Blankfeld, was the first company dedicated to direct-to-consumer testing for genealogy research. They initially offered eleven marker Y-Chromosome STR tests and HVR1 mitochondrial DNA tests. They originally tested in partnership with the University of Arizona.^{[7][8][9][10][11][12][13]}

The publication of The Seven Daughters of Eve by Sykes in 2001, which described the seven major haplogroups of European ancestors, helped push personal ancestry testing through DNA tests into wide public notice. With the growing availability and affordability of genealogical DNA testing, genetic genealogy as a field grew rapidly. 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.^[14] The number of firms offering tests, and the number of consumers ordering them, rose dramatically.^[15]

The Genographic Project

The original Genographic Project was a five-year research study launched in 2005 by the National Geographic Society and IBM, in partnership with the University of Arizona and Family Tree DNA. Its goals were primarily anthropological. The project announced that by April 2010 it had sold more than 350,000 of its public participation testing kits, which test the general public for either twelve STR markers on the Y-Chromosome or mutations on the HVR1 region of the mtDNA.^[16]

In 2007, annual sales of genetic genealogical tests for all companies, including the laboratories that support them, were estimated to be in the area of $60 million (2006).^[5]

Typical customers and interest groups

The earliest test takers were customers most often those who started with a Y-Chromosome test to determine their father's paternal ancestry. These men often took part in surname projects. The first phase of the Genographic project brought new participants into genetic genealogy. Those who tested were as likely to be interested in direct maternal heritage as their paternal. The number of those taking mtDNA tests increased. The introduction of autosomal SNP tests based on microarray chip technology changed the demographics. Women were as likely as men to test themselves. Further, Ancestry.com's simplification of matching brought a larger number of test takers, though the validity of their DNA matching and accompanying genealogy pairing were questioned.

Citizen science and ISOGG

Members of the growing genetic genealogy community have been credited with making useful contributions to knowledge in the field.^[17]

One of the earliest interest groups to emerge was the International Society of Genetic Genealogy (ISOGG). Their stated goal is to promote DNA testing for genealogy.^[18] Members advocate the use of genetics in genealogical research and the group facilitates networking among genetic genealogists.^[19] Since 2006 ISOGG has maintained the regularly updated ISOGG Y-chromosome phylogenetic tree.^[19][20] ISOGG aims to keep the tree as up-to-date as possible, incorporating new SNPs.^[21] However, the tree has been described by academics as not completely academically verified, phylogenetic trees of Y chromosome haplogroups.^[22]

Uses

Mitochondrial DNA and direct maternal lineages

mtDNA testing involves sequencing or testing the parts of the hypervariable region (HVR1 or HVR2) or the complete mitochondrial genome (mtGenome). An mtDNA test that only tests part of the hypervariable region may also include the additional SNPs needed to assign people to a maternal haplogroup.^[23]

Direct paternal lineages

Y-Chromosome DNA (Y-DNA) testing involves short tandem repeat (STR) and, sometimes, single nucleotide polymorphism (SNP) testing of the Y-Chromosome. The Y-Chromosome is present only in males and only reveals information on the strict-paternal line. These tests can provide insight into the recent (via STRs) and ancient (via SNPs) genetic ancestry. A Y-chromosome STR test will reveal a haplotype, which should be similar among all male descendants of a male ancestor. SNP tests are used to assign people to a paternal haplogroup, which defines a much larger genetic population.^[24][25]

Biogeographical and ethnic origins

Additional DNA tests exist for determining biogeographical and ethnic origin, but these tests have less relevance for traditional genealogy.

Preliminary results from a study by Pierre Zalloua of the American University of Beirut and Spencer Wells were published in the October 2004 issue of National Geographic. One of its conclusions is that "more than half of the Y-Chromosome lineages that we see in today's Maltese population could have come in with the Phoenicians."^[26]

Human migration

Genealogical DNA testing methods are in use on a longer time scale to trace human migratory patterns. For example, they determined when the first humans came to North America and what path they followed.

For several years, researchers and laboratories from around the world sampled indigenous populations from around the globe in an effort to map historical human migration patterns. The National Geographic Society's Genographic Project aims to map historical human migration patterns by collecting and analyzing DNA samples from over 100,000 people across five continents. The DNA Clans Genetic Ancestry Analysis measures a person's precise genetic connections to indigenous ethnic groups from around the world.^[27]

See also

References

Further reading

Books

• Carmichael, Terrence; Alexander Ivanof Kuklin; Ed Grotjan (2000). How to DNA Test Our Family Relationships. Mountain View, CA: AceN Press. ISBN 978-0-9664027-1-1.  Early book on adoptions, paternity and other relationship testing. Carmichael is a founder of GeneTree.
• Cavalli-Sforza, Luigi Luca; Paolo Menozzi; Alberto Piazza (1994). The History and Geography of Human Genes. Princeton, N.J.: Princeton University Press. ISBN 978-0-691-08750-4. 
• Cavalli-Sforza, Luigi L.; Cavalli-Sforza, Francesco; Mimnaugh, Heather; Parker, Lynn (1996). The Great Human Diasporas : The History of Diversity and Evolution. Reading, MA: Addison-Wesley. ISBN 978-0-201-44231-1. 
• Fitzpatrick, Colleen; Andrew Yeiser (2005). DNA and Genealogy. Fountain Valley, CA: Rice Book Press. ISBN 978-0-9767160-1-3. 
• Gamble, Clive (1996). Timewalkers : The Prehistory of Global Colonization. Cambridge, MA: Harvard University Press. ISBN 978-0-674-89203-3. 
• Jobling, Mark; Matthew Hurles; Chris Tyler-Smith (2003). Human Evolutionary Genetics : Origins, Peoples and Disease. New York, NY: Garland Science. ISBN 978-0-8153-4185-7. 
• Olson, Steve (2003). Mapping Human History : Genes, Race, and Our Common Origins. Boston, MA: Houghton Mifflin. ISBN 978-0-618-35210-4.  Survey of major populations.
• Oppenheimer, Stephen (2003). The Real Eve : Modern Man's Journey Out of Africa. New York, NY: Carroll & Graf. ISBN 978-0-7867-1192-5. 
• Smolenyak, Megan; Ann Turner (2004). Trace Your Roots with DNA : Using Genetic Tests to Explore Your Family Tree. Emmaus, PA; Rodale, NY: Distributed to the trade by Holtzbrinck Publishers. ISBN 978-1-59486-006-5.  Out of date but still worth reading.
• Pomery, Chris; Steve Jones (2004). DNA and Family History : How Genetic Testing Can Advance Your Genealogical Research. Toronto, Ontario, Canada: Dundurn Group. ISBN 978-1-5500-2536-1.  Early guide for do-it-yourself genealogists.
• Pomery, Chris (2007). Family History in the Genes : Trace Your DNA and Grow Your Family Tree. Kew, UK: National Archives. ISBN 978-1-905615-12-4. 
• Shawker, Thomas H. (2004). Unlocking Your Genetic History : A Step-by-Step Guide to Discovering Your Family's Medical and Genetic Heritage. Nashville, TN: Rutledge Hill Press. ISBN 978-1-4016-0144-7.  Guide to the subject of family medical history and genetic diseases.
• Sykes, Bryan (2002). The Seven Daughters of Eve : The Science That Reveals Our Genetic Ancestry. New York, NY: Norton. ISBN 978-0-393-32314-6.  Names the founders of Europe’s major female haplogroups Helena, Jasmine, Katrine, Tara, Velda, Xenia, and Ursula.
• Sykes, Bryan (2004). Adam's Curse : A Future Without Men. New York, NY: W.W. Norton. ISBN 978-0-393-05896-3. 
• Tagliaferro, Linda; Mark Vincent Bloom (1999). Complete Idiot's Guide to Decoding Your Genes. New York, NY: Alpha Books. ISBN 978-0-02-863586-6. 
• Wells, Spencer (2004). The Journey of Man : A Genetic Odyssey. New York, NY: Random House Trade Paperbacks. ISBN 978-0-8129-7146-0. 

Documentaries

• PBS (2003). The Journey of Man DVD. Broadcast aired in January 2003, Spencer Wells, host.

Journals

• Decker, A.E.; Kline, M.C.; Vallone, P.M.; Butler, J.M. (2007). "The impact of additional Y-STR loci on resolving common haplotypes and closely related individuals". Forensic Science International: Genetics. 1 (2): 215–217. doi:10.1016/j.fsigen.2007.01.012. 
• Dula, Annette; Royal, Charmaine; Secundy, Marian Gray; Miles, Steven (2003). "The Ethical and Social Implications of Exploring African American Genealogies". Developing World Bioethics. 3 (2): 133–41. PMID 14768645. doi:10.1046/j.1471-8731.2003.00069.x. 
• Elhaik, E.; Greenspan, E.; Staats, S.; Krahn, T.; Tyler-Smith, C.; Xue, Y.; Tofanelli, S.; Francalacci, P.; Cucca, F. (2013). "The GenoChip: A New Tool for Genetic Anthropology". Genome Biology and Evolution. 5 (5): 1021–31. PMC 3673633 . PMID 23666864. doi:10.1093/gbe/evt066. 
• El-Haj, Nadia ABU (2007). "Rethinking genetic genealogy: A response to Stephan Palmi". American Ethnologist. 34 (2): 223–226. doi:10.1525/ae.2007.34.2.223. 
• Fujimura, J. H.; Rajagopalan, R. (2010). "Different differences: The use of 'genetic ancestry' versus race in biomedical human genetic research". Social Studies of Science. 41 (1): 5–30. PMC 3124377 . PMID 21553638. doi:10.1177/0306312710379170. 
• Golubovsky, M. (2008). "Unexplained infertility in Charles Darwin's family: Genetic aspect". Human Reproduction. 23 (5): 1237–8. PMID 18353904. doi:10.1093/humrep/den052. 
• Gymrek, M.; McGuire, A. L.; Golan, D.; Halperin, E.; Erlich, Y. (2013). "Identifying Personal Genomes by Surname Inference". Science. 339 (6117): 321–4. PMID 23329047. doi:10.1126/science.1229566. 
• Larmuseau, M.H.D.; Van Geystelen, A.; Van Oven, M.; Decorte, R. (2013). "Genetic genealogy comes of age: Perspectives on the use of deep-rooted pedigrees in human population genetics". American Journal of Physical Anthropology. 150 (4): 505–11. PMID 23440589. doi:10.1002/ajpa.22233. 
• Larmuseau, M H D; Vanoverbeke, J; Gielis, G; Vanderheyden, N; Larmuseau, H F M; Decorte, R (2012). "In the name of the migrant father—Analysis of surname origins identifies genetic admixture events undetectable from genealogical records". Heredity. 109 (2): 90–5. PMC 3400745 . PMID 22511074. doi:10.1038/hdy.2012.17. 
• McEwen, Jean E.; Boyer, Joy T.; Sun, Kathie Y. (2013). "Evolving approaches to the ethical management of genomic data". Trends in Genetics. 29 (6): 375–82. PMC 3665610 . PMID 23453621. doi:10.1016/j.tig.2013.02.001. 
• Nash, Catherine (2004). "Genetic kinship". Cultural Studies. 18: 1–33. doi:10.1080/0950238042000181593. 
• Nelson, A. (2008). "Bio Science: Genetic Genealogy Testing and the Pursuit of African Ancestry". Social Studies of Science. 38 (5): 759–83. PMID 19227820. doi:10.1177/0306312708091929. 
• Royal, Charmaine D.; Novembre, John; Fullerton, Stephanie M.; Goldstein, David B.; Long, Jeffrey C.; Bamshad, Michael J.; Clark, Andrew G. (2010). "Inferring Genetic Ancestry: Opportunities, Challenges, and Implications". The American Journal of Human Genetics. 86 (5): 661–673. PMC 2869013 . PMID 20466090. doi:10.1016/j.ajhg.2010.03.011. 
• Sims, Lynn M.; Garvey, Dennis; Ballantyne, Jack (2009). Batzer, Mark A, ed. "Improved Resolution Haplogroup G Phylogeny in the Y Chromosome, Revealed by a Set of Newly Characterized SNPs". PLoS ONE. 4 (6): e5792. PMC 2686153 . PMID 19495413. doi:10.1371/journal.pone.0005792. 
• Su, Yeyang; Howard, Heidi C.; Borry, Pascal (2011). "Users' motivations to purchase direct-to-consumer genome-wide testing: An exploratory study of personal stories". Journal of Community Genetics. 2 (3): 135–46. PMC 3186033 . PMID 22109820. doi:10.1007/s12687-011-0048-y. 
• Tutton, Richard (2004). ""They want to know where they came from": Population genetics, identity, and family genealogy". New Genetics and Society. 23 (1): 105–20. PMID 15470787. doi:10.1080/1463677042000189606. 
• Van Oven, Mannis; Kayser, Manfred (2009). "Updated comprehensive phylogenetic tree of global human mitochondrial DNA variation". Human Mutation. 30 (2): E386–94. PMID 18853457. doi:10.1002/humu.20921. 
• Williams, Sloan R. (2005). "Genetic Genealogy: The Woodson Family's Experience". Culture, Medicine and Psychiatry. 29 (2): 225–252. doi:10.1007/s11013-005-7426-3. 
• Wolinsky, Howard (2006). "Genetic genealogy goes global. Although useful in investigating ancestry, the application of genetics to traditional genealogy could be abused". EMBO Reports. 7 (11): 1072–4. PMC 1679782 . PMID 17077861. doi:10.1038/sj.embor.7400843. 

External links and resources

• International Society of Genetic Genealogy
• MSNBC – Genetic genealogy links from MSN
• Guide to ancestry testing from Sense about Science
• "Debunking Genetic Astrology" a set of webpages at University College London