In a message dated 9/23/2011 3:09:05 A.M. Central Daylight Time, ikennedy_msdn2@hotmail.com writes: John, Personally I would argue the exact opposite, namely that most noble lines are extinct or near extinct, for a combination of statistical and social reasons. It was proven by nineteenth century statisticians that most lines die out over a period of many centuries. Iain, I think there may be a difference between "royal" lines in Scotland based on primogeniture and the derbhfine system in Ireland. I can see any one "royal" line dying out - but not so much a system based on cousins. The Dohertys have a clan head, Pascual Doherty, from Spain, who is perfect match the a large number of M222 Dohertys. In investigating the Byrnes DNA in the Trinity spreadsheets there is one large cluster of related samples (about 40) compared to less than 20 of the same surname who do not match and do no even match each other. This large cluster matches the Kinsellas and Kavanaghs of Leinster. So I think there is a difference between the two systems. John