People seem to think that DNA testing is only useful for two things: 1) To prove or disprove that a particular person was one of your ancestors and therefore extend your family tree back one or several generations. 2) To say where your extremely distant origins lie, e.g. that your remote ancestors entered Europe from the Middle East 20,000 years ago. However, by comparing your results with those of other people you can learn about the place of origin of more recent lines even if you are unable to extend your paper trail, as I discover after a y-DNA (i.e. the paternal line) test with Ancestry.com over two years ago. The earliest ancestor on my purely paternal line that I have much information about is 4 generations back - my 2xgreat grandfather, David Davies. He was born in Carmarthenshire in about 1818 and died in Merthyr Tydfil on 9 March 1889. Unfortunately I don't know exactly where in Carmarthenshire he was born. Most censuses just give "Carmarthenshire" as his place of birth. Two are more specific but they don't agree! One said "Carmarthen Town" but another said "Llanwenyd." Unfortunately there is no such place as "Llanwenyd." The census enumerator probably did not speak Welsh since he obviously had trouble with the place name. Perhaps it should be the parish of Llanfynydd but I am not sure. When David Davies married my 2xgreat grandmother, Jemima Evans, in 1839, his father's name was also listed as "David Davies" but that is all I know about him. However, after my first DNA test (with Ancestry.com) I also added my results to the The Sorenson Molecular Genealogy Foundation Database. http://www.smgf.org/ Although my closest matches (with people who had taken tests with a reasonably large set of markers, 20 or more) were actually very distant ones I was able to deduce some interesting geographical information from them. The two "closest" matches had listed their earliest known ancestors as follows. Timothy DAVIES b. 14 Sep 1748 Ty-Yn-Y-Berth, Nantymol, Llangyfelach, Glamorgan, Wales Most Likely TMRCA 21 generations, 651 years ago. Llangyfelach is about 22 miles east of Carmarthen Town where David Davies may have been born. Thomas JOHN b. 22 Jan 1820 Woodroach, Mathry, Pembrokeshire, Wales Most Likely TMRCA 29 generations 899 years ago. Mathry is about 33 miles west of Carmarthen Town. Even if my earliest known paternal ancestor, David Davies, was not born in Carmarthen Town but some other part of the county, he would still have been born in between the birth places of the earliest known ancestors of two men with whom I share common ancestors about 6 centuries and 9 centuries ago respectively. Therefore those remote common ancestors would almost certainly also have lived in southwest Wales. Consequently there is good evidence that my purely paternal line goes back the best part of a thousand years in southwest Wales. For all I know they might have been living in that part of Wales for much longer it is possible that proof or disproof will be obtained in future if other people with whom I share a common paternal ancestor more than 9 centuries ago have also been able to determine the minimum length of time their paternal ancestors lived in southwest Wales by using similar analysis to the one I have described. What about other lines? When you go back many generations you have a huge number of ancestral lines and Y-DNA analysis tells you about only one of them, doesn't it? Well, it is true that the y-chromosone is only inherited by males. However, if all the males on that line for the past 9 centuries or so were born in southwest Wales then their mothers were obviously living in southwest Wales too! Therefore a lot of the maternal lines that join my paternal line must also have roots in southwest Wales that go back a long way. Autosomal DNA tests, as offered by Family Tree DNA can find matches across any branch of your family tree back to the level of 4th cousins, and can give some indication of more distant matches too. I think Ancestry.com are also planning to offer autosomal DNA tests. So far, unfortunately, I have not been able to extend my family tree any further back but, as I have indicated, I have still learnt something about my origins from DNA tests. The more people that are tested the more chance there will be of matches with someone who has the necessary evidence to extend my tree. Therefore DNA tests should be regarded as a long term investment. Roy