Some time ago I decided to take a 37 marker DNA test. It was a wait and I was not expecting very much - but much to my astonishment I was immediately matched with two gentlemen called Blood. When we compared family trees - it was clear that the common ancestor was before 1600, probably as early as 1500. I began to research the family in detail and despite a paucity of both paper and DNA information, it became clear that all English BLOODs (who are quite numerous in the USA) are from a single ancestor, probably Thomas Blud ~1475, who lived near the Dove River in Derbyshire.
This was at considerable odds with the status quo, which held we were all related to the Irish adventurer Col Thomas Blood who stole the crown jewels. Some very early misinformation was in the records of this rich Irish BLOOD family which showed an (unlikely) connection to the much more humble family of the Midlands. When we investigated the old story closely we found that virtually every detail was fabricated and appeared to have been concocted about 1660, most likely by the blackguard Col Thomas himself, trying to curry favour with the English.
This discovery did not endear us to the New England Bloods, who were all keen to be related to this ruffian.
The second success story concerns the Coads and Coodes of Cornwall on my mother's side, on whom I have been doing a detailed one-name study. Records in Cornwall are probably the best in England, but start to peter out in the 1600s. As a result, I ended up with about 8 "tribes" of COAD who were probably related. We also knew from old tax and muster records that the variant had not existed before 1600, and everyone had been known as CODE or COODE.
First DNA results were not encouraging - we ended up with three non-matching samples of different families. But the paper cousins who tested were able to show they were closely related, with DNA that was unchanged since 1700 - particularly the descendants of our oldest certified COADs who hail from the quaint little port of Looe in SE Cornwall and were mostly a family of blacksmiths.
For my own small branch of the family, all miners from a single ancestor Samuel born about 1666 near Truro, I conducted an Australia -wide mailing to try to locate my own COADE cousins. I found a friendly relative living only a few km away in Melbourne and after a year he finally got around to taking the test in Feb. - we matched the Looe Coads, and none too closely, indicating a common ancestor no later than 1500 or so.
The only way we can see a COAD could have got across to West Cornwall so early is through the intermediary of the COODEs, a rich and very eminent family who have lived in the area since about 1580. The Coodes were initially sceptical of a possible relationship with the COADs and unwilling to participate, but as the paper and DNA evidence has mounted, they have conceded that we are likely all descended from the CODEs who have lived in the Liskeard area almost continually since 1300 or so and are one of the oldest hereditary surnames in Cornwall. We hope this will soon be further confirmed through DNA.
The fact is we come from a very ancient family who were already well differentiated into separate family groups by the 1500s, and some of which "slipped under the radar" because they were yeomen rather than gentry. In this circumstance there is only one way to proceed, and that is by DNA testing two surviving males of each family, preferably distant cousins.
There is still a lot to do - we need to find out why those other families diverged and when, and eventually DNA will give us the answers. I strongly suggest to anyone involved in researching the history of a surname that they complement their paper efforts with a DNA project - if properly caried out the results will be more than worth it.