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Archiver > CHESHIRE > 2004-03 > 1079309728


From: John Phillips <>
Subject: [CHS] A QUESTION OF MATHEMATICS II
Date: Mon, 15 Mar 2004 00:15:28 +0000 (GMT)


Hi all


Dear All



First of all many thanks to all those who reacted to my “Question of Mathematics”, and particularly those who pointed out my ‘deliberate’ mistake! I should of course have said that we had 4096 10x great grandparents, and 8090 possible or theoretical direct ancestors to that point. Taken back to 1200ish that figure becomes over 200 million which is clearly an impossibility.



I am interested in the question of cousins marrying which is of course almost the only way of fitting the number of ancestors into the likely population figures. One other way is by introducing bloodlines from foreign parts. I have two from the Netherlands and two from Germany which reduces, up to a point, the need for cousins to marry to make the statistics fit.



Eve Mclaughlin mentioned the ‘triangular’ form of the ascent/descent graph, where the further back you go, the fewer direct ancestors you actually have, (because of cousins marrying.) I would be interested to know the statistics of this because as far as I am aware I do not have a single instance (in the direct line) of this happening. I have identified a 7th cousin in the Netherlands. We have a 6x great grandfather in common who we only discovered when we put the results of our separate researches together. Genetically we are about as different as we could be but still cousins nevertheless. Had I married Marco’s sister, theoretically we would have narrowed the gene pool and therefore reduced the number of ancestors on our kids’ tree by 2, but the odds on finding people with that kind of connection must be remote for most people.



So what are the chances of finding cousins marrying cousins? In communities where the ubiquitous ‘ag lab’ tilled the fields for generations, and didn’t move far from the backside of his horse for most of his life, the scope for close relatives intermarrying must have been higher. (Also the scope for a little rolling in the hay as well, so relationships may not have the genetic lineage quite as the church registers have them!) In these cases one would probably have to study the population of the whole village in order to discover who was directly related by marriage to whom, and even if the church registers go back to 1560s one would have to have probably 2-3 generations sorted out before the aforesaid marriage in order to establish whose cousin was whom. So the limit of certainty on this can not go back much further than 1650 at best. Add to that the problems with the lack of entries in registers during the Commonwealth, and the significant numbers of Nonconformists and Diss!
enters
for whom records do not exist and the likelihood of identifying ancestors before 1660 becomes extremely difficult unless you can lock in to an established pedigree.



So the serious question to all this is: What is the likely number of direct ancestors that anyone could reasonably identify? Of the possible 8090, I have managed to identify, with some degree of certainty, and I’ll put it no better than that, 185!! And I thought I was doing well. This includes one 11 x great grandparent. I have a number of brick walls which I have absolutely no hope of breaking down, and a few more which might respond to some more available information in the future. Lines in Ireland, and a few more common names are fraught with problems. When, if ever, should a reasonably sane person call it a day?



I’m grateful for everyone’s observations, and for the fact that this seems to have struck a chord with so many. Like you, all I really need is answers!



So as not to clog the airways, please respond to me direct if you wish to carry the discussion on. Although this is a legitmate line of enquiry, I do not wish to incurr the wrath of the listowners. Or, if they give the OK, please carry it on in the public domain. I think, and hope that it will respond to further deliberation.



Best wishes,



John Phillips

(Yorkshire, UK)



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