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Evaluating a Big Y match

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  • T E Peterman
    replied
    What counts is unshared novel variants. A lot of the 78 are shared with everyone else in your haplogroup. To be clear, novel doesn't mean unique, it just means new, as in just discovered.

    I can see a benefit in testing people with closely related patrilines. Here is my thinking. Many of the early immigrants to America were born between 1580 & 1650. Assuming 135 years per novel variant, consider the years 1580, 1715, 1850, 1985. Such an immigrant may have descendants who have incurred as many as 3 novel variants since immigrating. If someone born in 1985 had no unshared novel variants with a match, we would know that the MRCA for the two was likely born after 1850. If he had one unshared novel variant, we would know that the MRCA was likely born after 1715. Two unshared novel variants: MRCA likely born after 1580. These tiny subclades would be a more sound way of determining distance to the MRCA than y-str data.

    Timothy Peterman

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  • 1798
    replied
    Originally posted by dna View Post
    I am running a small surname project, we did not originally intend to test family members that closely related (both in paper trail and Family Finder and Y-DNA), it turned out that way - a very long story.

    78 novel variants are shared between these two individuals, while with the other matches they share at most 55-57 novel variants.

    It might be of interest to you that none of their twenty Big Y matches is shown by FTDNA as a match in their Y chromosome STR tests (from 12, through 25, 37, 67 to 111 markers). I went through 1000+ entries in Advanced Matching for 12 markers to make sure about that.

    However, in Y-DNA12 results one of the matches differs by 1 in DYS393, and another by 1 in DYS385.

    W. (Mr.)
    So 78x90 is around 7000 years for a TMRCA.

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  • dna
    replied
    Originally posted by Brunetmj View Post
    dna
    Thanks
    That's the kind of information I was looking for. That is , a sense of what two related people might share in the way novel variants. I wasn't clear about the 78 novel variants , do they share that with other? Or with you. If with each other how many do they share with you?
    I am running a small surname project, we did not originally intend to test family members that closely related (both in paper trail and Family Finder and Y-DNA), it turned out that way - a very long story.

    78 novel variants are shared between these two individuals, while with the other matches they share at most 55-57 novel variants.

    It might be of interest to you that none of their twenty Big Y matches is shown by FTDNA as a match in their Y chromosome STR tests (from 12, through 25, 37, 67 to 111 markers). I went through 1000+ entries in Advanced Matching for 12 markers to make sure about that.

    However, in Y-DNA12 results one of the matches differs by 1 in DYS393, and another by 1 in DYS385.

    W. (Mr.)

    Leave a comment:


  • Brunetmj
    replied
    dna
    Thanks
    That's the kind of information I was looking for. That is , a sense of what two related people might share in the way novel variants. I wasn't clear about the 78 novel variants , do they share that with other? Or with you. If with each other how many do they share with you?

    Leave a comment:


  • dna
    replied
    Originally posted by Brunetmj View Post
    I did a search on this topic but they ended up being subclade specific. Is there a quick way , that is a general way, to evaluate a Big Y match ? For example the highest novel variant matches I have are 54. However it is shown this novel variant match happened a few thousand years old. How many novel variants would a person share if the match was 500 years ago?
    Could someone summarize a quick and dirty evaluation method.?
    I am particularly interested in more recent times (last 600 hundred years). What would their novel variant sharing look like? What should I look for?
    I did some calculations for a grand-nephew/grand-uncle pair in R-M269. That was quite tedious, so I wish FTDNA displayed such information by default.

    They are listed as sharing 78 novel variants.

    Excluding those that do not have Confidence High or are not reliable (locations 222xxxxx, 223xxxxx, or 224xxxxx), they share 20 novel variants that nobody else among their matches has.

    After excluding locations 222xxxxx, 223xxxxx, or 224xxxxx, the interesting part is that
    • one of them has 8 novel SNPs not shared with the other, 5 of these are such that none of his Big Y matches has them, 3 are shared with another, another four and another nine of his matches;

    • the second one has 3 novel SNPs not shared with the other, 2 of these are such that none of his Big Y matches has them, 1 is shared with another five of his matches.

    W. (Mr.)

    P.S.
    I doubt that these two individuals differ by 7 genealogically significant SNPs, thus quite possibly those 7 SNPs (they do not share) occur with many individuals all across the tree. FTDNA has that information and should be labelling novel SNPs accordingly.

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  • Brunetmj
    replied
    Thank You for your suggestions

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  • lgmayka
    replied
    Originally posted by Brunetmj View Post
    I suppose to find someone from more modern times I would have to have a list of recent snp's and just watch for those.
    It is easier and more reliable, though a little more expensive, simply to contact your nearest Big Y matches and offer to submit their BAM files to YFull (at your own expense, if necessary). YFull will then estimate TMRCAs for you.

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  • Brunetmj
    replied
    Thank you lgmayka. I am on Yfull and all my results are in the hands of experts. I have seen the section which you describe and have used it. I suppose to find someone from more modern times I would have to have a list of recent snp's and just watch for those.

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  • Brunetmj
    replied
    In several of the 54 to 52 novel variant matches it does not list a difference in the differences column. So your suggestion is a good one, but for me not quick. Well maybe just answer this question, how much novel variant exists is say someone who shared a common ancestor but in the last 500 years? I guess to narrow down my question is there a relationship between the novel variants shared and the closeness in time to the person who shares them ? What is the average novel variants shared by family members?

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  • lgmayka
    replied
    Originally posted by Brunetmj View Post
    Could someone summarize a quick and dirty evaluation method.?
    I am particularly interested in more recent times (last 600 hundred years). What would their novel variant sharing look like? What should I look for?
    1) Go to your Big Y Matches page.
    2) Under the column title "Shared Novel Variants", click on the dropdown box (which initially says "Show All").
    3) In the resulting dropdown list, scroll down to the bottom.
    4) Look for entries with "(1)". These should be the SNPs that you share with exactly one other person. But beware, some or all of these may be in unreliable segments of the Y chromosome (and hence are not valid grounds for a match). In particular, locations beginning with 222, 223, or 224 are usually unreliable.
    5) Look for entries with "(2)", "(3)", etc. These should be SNPs that you share with just a few other men.

    Unfortunately, this is all very error-prone for anyone but experts. That's why I routinely suggest ordering a professional analysis from YFull.

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  • dna
    replied
    Not what you had asked for

    A quick check. Do you have any known SNPs that you two differ on? If yes, do they have MRCA time estimate on YFull?

    Leave a comment:


  • Brunetmj
    started a topic Evaluating a Big Y match

    Evaluating a Big Y match

    I did a search on this topic but they ended up being subclade specific. Is there a quick way , that is a general way, to evaluate a Big Y match ? For example the highest novel variant matches I have are 54. However it is shown this novel variant match happened a few thousand years old. How many novel variants would a person share if the match was 500 years ago?
    Could someone summarize a quick and dirty evaluation method.?
    I am particularly interested in more recent times (last 600 hundred years). What would their novel variant sharing look like? What should I look for?
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