Firstly, it seems probable that rather than the Blakes of England and Ireland being branches of the same family, that they are, in fact, different families using the same surname.

Nevertheless, there are a number of groups for the Blake family of the British Isles generally; and, based on known genealogical charts, it would seem probable that this is the result of Blake being a characteristic surname. It is hoped that this surname project will attract more members with British Isles ancestry; and that this will enable further associated research.

The number of distinct groups has grown rapidly attesting to the thought that Blake, as a surname, arose partially because it is a characteristic surname. However, the discovery of a merchant of Rouen Richard le Blak requesting a licence for market in 1274 has certainly added to the mystery surrounding the many Blake lines. I do blog on the Blake family most days (at the moment I am transcribing all the PCC wills for the Blake families in England) and if interested can be viewed at:  http://kippeeb.blogspot.ca/

Secondly, several descendants of the Galway Blake family have determined the genetic signature yDNA for this family grouping. See the yDNA results for the Galway Blake family on this website. 

Thirdly, initial analysis of test results had suggested the likelihood of a sub-branch within the County of Norfolk in England. In this regard, it had been asserted by many researchers that (2) different Y-DNA haplogroups have a common ancestor in Peter Blake of Wimbotsham in around 1500 AD. However, analysis: -

• of associated y-DNA test results;

• combined with an analysis of associated genealogy charts;

has revealed that the relevant sub-branch does not exist. In fact, it has now been proven that the Theophilus Blake who married Margaret (Kennett?) did not descend from the Blakes of Hampton, New Hampshire, U.S.A.; and that he immigrated to the U.S.A. in his own right and is from a different branch of the Blake family.