From DNA evidence in crime cases to population-wide studies of genetic disease, immensely-powerful DNA technology is transforming our world. Understandably, members of the public tend to respect and trust scientific professionals who can wield these powerful new tools.
It is also inevitable that some will seek to abuse this trust, often with a commercial motive but sometimes the motive seems to be promotion of a world view or political philosophy. In these pages we will focus on "genetic ancestry" testing: the use of your DNA to make statements about your "deep ancestry", such as where your ancestors lived hundreds or even thousands of years ago, and perhaps their cultural identities (such as Celts, Vikings, Mongols etc). This type of testing is distinct from genetic genealogy which uses DNA in combination with genealogical and historical records, and which is therefore mainly focused on recent centuries.
Genetic technology can tell us about the DNA of people alive today in different parts of the world. Recently, exciting progress has been made in recovering DNA from ancient burial sites, but it remains broadly true that making inferences into the past from DNA requires assumptions and mathematical models, and input from other fields such as history, archaeology and studies of historic geography and climate. New DNA genotyping and sequencing technology, and improved statistical models, have accelerated progress, but inferences still need to be accompanied by caveats about the assumptions and approximations made, and by assessments of uncertainty.
We all love stories about our past, and for many it's too tempting to cut corners, draw inferences based on only superficial analysis of the data, and ignore the uncertainty. A public unaware of the distinctions may be misled into thinking that DNA-based inferences about the past are as reliable as a DNA profile match. Usually they are not.
We have created these web pages to help interested non-scientists to be skeptical consumers of genetic ancestry information, and to try to distinguish genetic ancestry from genetic astrology. We highlight some of the doubtful claims that have been brought to our attention: scientific-sounding claims that we think are flawed, exaggerated or not well supported by the evidence, and that appear to be driven by a commercial motive or some agenda other than the advancement of knowledge. We also aim to help readers find some of the best available scientific evidence, and provide an overview of what can and can't be said about genetic ancestry.
Many have contributed to these pages, the primary authors are
- David Balding, Professor of Statistical Genetics, UCL and University of Melbourne
- Debbie Kennett, Honorary Research Associate, UCL
- Mark Thomas, Professor of Evolutionary Genetics, UCL
- Adrian Timpson, Research Associate, UCL
The selection of material for inclusion on this site is somewhat ad hoc in nature, and these pages are constantly evolving. Feedback and comments are most welcome, for example, suggestions for bad genetic ancestry science to include on these pages. You can use the twitter feed to the right, the feedback form below, or email us. Note that we are unable to offer individual advice on testing. We suggest that you ask for advice on one of the many genetic genealogy mailing lists and forums listed in the ISOGG Wiki.