Quite a interesting discussion on DNA testing and matches. Hopefully not too many readers became confused and discouraged. The ISOGG website is a reliable source of information. Accurate descriptions using these e-mail posts are sometimes difficult. Just a couple comments to for clarity. When discussing matching YDNA matches haplotypes between two different men, the number of markers being discussed is very important. Matches at the 12 marker level are very common and only indicate possible ancient paternal line shared ancestry, much earlier than the use of surnames. At the 12 marker level or less it is even probable that the shared paternal line ancestor lived many thousands of years ago and had a very different looking haplotype, that would be referred to as a match due to state, read that as just coincidence there is a match within the recent generations. Matches due to state are less probable as more markers are tested. A match of 36 markers can indicate shared paternal line ancestry within 5 generations, 67 markers can be within 4 generations and matches with 150 markers are likely within two or three generations. All that is based on statistics of tests conducted on people with known shared paternal line anc! estry. There have been exceptions to the above, but they are rare. You can read about that on Family Tree DNA's website 'questions and answers' or the ISOGG newbie (someone new to DNA testing for genealogy) website as well as many other websites and texts. When discussing matches, it is necessary to state how many markers match and the number tested. On surname matching, doing genealogy research we often find people changing their surname, to better fit in, don't want to be identified with their past or with their relatives, identify more with the mother's or wife's family, or for another reason, and then there is adopting the surname due to adoption by kin or a non related family, which is more prevalent the further you go into the past, and then there are the re-marriages and the occasional fatherhood outside of marriage situation, so, it is not uncommon to find two men who are paternal line descendants of the same man with different surnames, it happens. Finding out why can be part of the adventure. Also, keep in mind that most western Europeans really did not identify with a surname prior to the 17th or 18th century (surname usage in western Europe became widespread only in 10th to 13th centuries so the Norman's could maintain tax records), even later for eastern Europeans, can be further back for mediterranean Europeans. Surnames had more importance to families who had stature and/or wealth, which were the extreme minority. Hope this helps someone. Enjoy the day.