Discussion:
OT: DNA Visualizations
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joseph cook
2020-07-18 23:42:21 UTC
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With the discussion of matches at 7-8cm, I agree that these matches are useless without other context or a paper trail.

I create charts like the following for all my DNA matches that also have a paper trail. These particular ones go back about as far as I find autosomal DNA connections can be useful without an extreme amount of additional information.

Still, for matches at this distance, both the paper trail AND common matches/common segments of matches are required to have any confidence that the low level is the result of the match. And of course it is just evidence, not "proof" since at this distance it would take much additional work to sort out possibilities like a possible half-relationship at the root person. But it does provide some evidence as you compile this where your NPE occured or probably did not occur.

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Joe C
Ian Goddard
2020-07-19 11:34:35 UTC
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Post by joseph cook
http://branchpike.com/DNA-Byam_a.png
Is your Byam a variation on Byram? If so do you have any connection
back to the medieval Huddersfield Byrams?

Ian
joseph cook
2020-07-19 12:20:05 UTC
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Post by Ian Goddard
Post by joseph cook
http://branchpike.com/DNA-Byam_a.png
Is your Byam a variation on Byram? If so do you have any connection
back to the medieval Huddersfield Byrams?
No known or suspected connection here. The Byam immigrants to the United States were George and Susanna Byam who were in Salem, Mass by 1640. The family "tradition" is that they were from Southwestern England or Wales, but I give this no credence whatsoever honestly. There were "Biam" "Byham" "Byam" familes recorded in the 17th century widespread in Kent and Suffolk.

However, I believe the surname "Byam" and "Byram" are likely unrelated etymologically.

--Joe C
Ian Goddard
2020-07-19 13:07:56 UTC
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Post by joseph cook
Post by Ian Goddard
Post by joseph cook
http://branchpike.com/DNA-Byam_a.png
Is your Byam a variation on Byram? If so do you have any connection
back to the medieval Huddersfield Byrams?
No known or suspected connection here. The Byam immigrants to the United States were George and Susanna Byam who were in Salem, Mass by 1640. The family "tradition" is that they were from Southwestern England or Wales, but I give this no credence whatsoever honestly. There were "Biam" "Byham" "Byam" familes recorded in the 17th century widespread in Kent and Suffolk.
However, I believe the surname "Byam" and "Byram" are likely unrelated etymologically.
Thanks, Joe.
Jan Wolfe
2020-07-19 14:10:01 UTC
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Post by joseph cook
With the discussion of matches at 7-8cm, I agree that these matches are useless without other context or a paper trail.
I create charts like the following for all my DNA matches that also have a paper trail. These particular ones go back about as far as I find autosomal DNA connections can be useful without an extreme amount of additional information.
Still, for matches at this distance, both the paper trail AND common matches/common segments of matches are required to have any confidence that the low level is the result of the match. And of course it is just evidence, not "proof" since at this distance it would take much additional work to sort out possibilities like a possible half-relationship at the root person. But it does provide some evidence as you compile this where your NPE occured or probably did not occur.
http://branchpike.com/DNA-Byam_a.png
http://branchpike.com/DNA-Callahan_a.png
Joe C
Joe, how do you ever have time to create such charts for all of your distant DNA matches who have paper trails??? Do you check the steps in their paper trails?
taf
2020-07-19 15:09:53 UTC
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Post by Jan Wolfe
Joe, how do you ever have time to create such charts for all of your distant
DNA matches who have paper trails???
I haven't made charts but have identified such lines for about 100 such distant relatives. Lockdowns result in a lot more free time.
Post by Jan Wolfe
Do you check the steps in their paper trails?
This is a big issue. At some point one has to do the best one can with what is available, but it is always with the caveat that unless one confirms the entire descent from scratch (and life is too short to do this with every distant match), one could be basing the connection on a set of false assumptions. The number of times I have heard people say that DNA proved a hypothesized link because Ancestry showed a tree that matched what they had in their pedigree . . . Ancestry showed the match that way _because_ it is what they had in their pedigree. It is nothing but a big exercise in begging the question, and there is nothing different about doing it by hand - garbage in, garbage out.

taf
joseph cook
2020-07-19 19:21:06 UTC
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Post by Jan Wolfe
Post by joseph cook
With the discussion of matches at 7-8cm, I agree that these matches are useless without other context or a paper trail.
I create charts like the following for all my DNA matches that also have a paper trail. These particular ones go back about as far as I find autosomal DNA connections can be useful without an extreme amount of additional information.
Still, for matches at this distance, both the paper trail AND common matches/common segments of matches are required to have any confidence that the low level is the result of the match. And of course it is just evidence, not "proof" since at this distance it would take much additional work to sort out possibilities like a possible half-relationship at the root person. But it does provide some evidence as you compile this where your NPE occured or probably did not occur.
http://branchpike.com/DNA-Byam_a.png
http://branchpike.com/DNA-Callahan_a.png
Joe, how do you ever have time to create such charts for all of your distant DNA matches who have paper trails??? Do you check the steps in their paper trails?
Typically only to a point. I have already traced down most of the descendants of my 4x-great-grandparents (mostly in an attempt to letter-write them all seeking photographs); this has led (over 25 years) to about 25K folks connected in my tree. I add zero without a source.

But.. much of the time I already have their grandfather or great-grandfather recorded... so if I contact them and they say "this is my grandfather", I usually will just accept it at their word, and record that with the note "info from XX grandchild". I don't ask them to provide vital records :). Their word about relatives they know personally along with the DNA match is "good enough" for my purposes, and as taf says, there is only so much time in the world. If I was ever trying to really prove or publish something, I would then go back and dedicate the time to be more careful....but for likely 5th cousins? Very low on my to do list. Since the purpose of the charts was to identify potential errors (or mystery fathers) in the paper trail lines, and *most importantly* the information in these charts (cm matches) will be *totally unavailable* in 100 years. Ancestry.com will likely not have this info in this same form, and certainly it will be impossible to contact the people who donated for info at that time. So recording it for future generations to evaluate and use in their follow-on research is critical. The data is ephemeral.

Of course, the fun of DNA is that there always unexpected things. A DNA connection I couldn't figure out how the heck they could be connected turned out to be the result of an extremely brief first marriage, where the divorced wife and infant took off quite a ways west. No amount of paper research would have likely uncovered the connection.

Another half-uncle popped up whose name was changed in infancy and off to another family. Only after they popped up in the DNA, and after contacting the family was it possible to put the pieces together and "find" them.

--Joe C
wjhonson
2020-07-19 20:07:32 UTC
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The easiest way to triangulate is to use the free myHeritage cluster mapping.
It will at least give you some idea of who is related to whom
s***@mindspring.com
2020-07-21 04:56:25 UTC
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Post by joseph cook
With the discussion of matches at 7-8cm, I agree that these matches are useless without other context or a paper trail.
I create charts like the following for all my DNA matches that also have a paper trail. These particular ones go back about as far as I find autosomal DNA connections can be useful without an extreme amount of additional information.
Still, for matches at this distance, both the paper trail AND common matches/common segments of matches are required to have any confidence that the low level is the result of the match. And of course it is just evidence, not "proof" since at this distance it would take much additional work to sort out possibilities like a possible half-relationship at the root person. But it does provide some evidence as you compile this where your NPE occured or probably did not occur.
http://branchpike.com/DNA-Byam_a.png
http://branchpike.com/DNA-Callahan_a.png
Joe C
A couple of brief comments:

1. Although autosomal DNA (along with a paper-trail match) can often be used to show that a NPE probably did not occur, showing that a NPR did occur generally requires y-DNA evidence once you are more than a couple of generations back. More distant scenarios can be concocted in which autosomal DNA could be used to prove a NPE, but in practice you would seldom get enough evidence to rule out other possibilities.

2. In most cases, making conclusions from 7 cM matches is dangerous, even in the presence of a paper-trail match. In general, I ignore matches which are less than 10 cM as not being worth the effort, and even longer matches can be false positives. I also have DNA tests for my two siblings, and the only exception I make is that I will include matches of less than 10 cM in my analysis if one of the three siblings has a match of 10 cM or more on the same segment. Often the other matches occur when one is just above 10 cM and the other just under, but even more useful information can sometimes be obtained from short matches if one of the siblings has a crossover in the relevant segment.

Stewart Baldwin

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