As mentioned in the previous post, I urge that Y-chromosome DNA (STR) testing should be the first type of DNA test to consider.But when you are ready to go beyond traditional testing, autosomal SNP testing can provide tantalizing matches to relatives that Y-chromosome testing cannot hope to reveal.By its nature, autosomal testing will miss many matches to specific distant relatives (as discussed in my previous post).But it will almost randomly reveal matches to many, even hundreds (up to a thousand, for 23andMe) of people in the database -both male and female, from both paternal and maternal lines, and with a common ancestor potentially going back over a thousand years ago (usually much more recent).Yet anyone identified as a match by FTDNA or 23andMe is virtually certain to be a bona fide relative, due to the way the DNA matching is done.Brits may find occasional matches to residents of Norway, Germany, Italy, etc. (including the colonies)who are so distant that there is little hope of discovering how you and they are related.But the connection IS there, if you can figure out what it is.
Autosomal DNA testing is becoming more common among adoptees who want to find out more about their birth families (not just for ancestry but also for health-related information).It is also useful to provide information about long-forgotten ethnic origins.
Jim Bartlett, who wrote the first post in this thread, has had incredible luck teasing out his connections to 10 matches so far (out of near a hundred matches reported to him).Most people will not be so lucky as to work out 10 connections in a short time (based on my own experience and that of many others). Not only luck, but also an extensively researched family tree is required to make the most of the matches that you will find by autosomal testing -and often your match needs to have an equally extensively researched family tree.(Most people's family trees, mine included, have a large number of missing links, particularly on the distaff side.)But even without having a well-researched family tree, autosomal testing with either of these companies will show you many, many bona fide relatives that you previously had no clue about.There can be some surprises, and it can be very exciting.I personally look at it as a game, but in contrast to most games this one is grounded in reality.
There are currently two companies doing autosomal DNA testing at consumer prices (actual prices and commercial web sites SHOULD NOT be mentioned on these boards).Jim mentioned FTDNA; the other company is 23andMe.Each has their own advantages and disadvantages.Based on a small informal poll I took among DNA project administrators with experience with both companies, at this point neither company has a clear advantage for those interested in ancestry research but not health implications of the tested DNA.FTDNA focuses on ancestry research and offers no health-oriented information.People you match in their database are more likely to be able to provide you with information about their ancestors.Although 23andMe has a FAR larger database than FTDNA, far more of their customers lack ancestry information.The informal poll suggested that despite 23andMe's larger database, and MANY more matches shown, in practice there is roughly equal chance of establishing documented connections with the matches provided by the two companies.Because of 23andMe's focus on health, their result for each individual SNP is more likely to be accurate.(FTDNA's minor inaccuracies at the individual SNP level do not affect its accuracy at the level of finding relatives.)So if you are interested in health information as well as ancestry information, 23andMe is clearly your best choice; otherwise FTDNA is also highly recommended.
Richard Thrift Thrift /Frith /Firth Surname DNA Project administrator, rtx at cox dot net