Once there were companies offering to sell us books or coats of arms for our family name - now we're being offered DNA tests (even Ancestry.com is doing it). But is it of any value to us?
If you imagine your family tree, it's in the shape of an inverted Christmas tree, with you at the bottom, and rows of direct ancestors that get ever wider as you go back through the generations.
The left-hand edge of the tree is your paternal line; at the far right is your maternal line. Most genealogical DNA tests analyse the Y-chromosome, which passes down the paternal line, or mitochondrial DNA, which passes down the maternal line.
Go back 10 generations and (ignoring cousin marriages) you've got 1024 direct ancestors. Even if you spend hundreds of pounds and take both tests, they are only telling you about 2 of those ancestors, who have provided less than 1% of your DNA!
So is there a place for DNA testing in genealogy? I believe that there is, provided you're using the information to test a specific hypothesis