No announcement yet.

GEDmatch autosomal comparison - is this an exact match?

  • Filter
  • Time
  • Show
Clear All
new posts

  • GEDmatch autosomal comparison - is this an exact match?

    I need some clarification on whether or not two autosomal kits (my Dad's - 1 ancestry, 1 FTDNA), are exact matches or extremely close matches.

    There was a possible lab error made on his FTDNA Family Finder results, and I assume they are re-running his test.

    In the meantime, I decided to determine how far off the two existing kits are on GEDmatch, so I did a One-to-One.

    Interestingly, the result showed a green bar (Base Pairs with Full Match) on every chromosome 1-22, and a blue bar (greater than 3centiMorgans) below, on every chromosome 1-22. Largest segment was 214.5cM, Total of segments >3 cM 3,585.8 cM.

    The only differences were about half of the chromosomes had a tiny red vertical line or two and up to 2 or 3 Start Location/End Locations.

    It seems to me that these two existing kits match very well, and I would have expected much greater differences if this was indeed half Dad's DNA (H R-M269) and half another man's DNA (someone named Simpson with H-Ild).

    Any thoughts or suggestions?

    Thank you very much.

  • #2
    You are seeing comparison results from the same person (or an identical twin). The solid green bar is an exact match. The occasional red vertical lines are occasional single SNP mis-matches due to genotyping errors, or possibly, some single SNP result that the GEDmatch matching algorithm can't handle. The occasional single SNP mismatches are normal.

    Last edited by JOlson; 10 October 2013, 01:36 PM.


    • #3
      Thank you. Wouldn't this rule out lab error on these two separate kits then? One from ancestry, one from FTDNA.

      It was suggested that Dad consider getting the Geno test done through National Geographic, possibly a new SNP.

      Is this unusual (a new SNP?), or routine?

      Thoughts please.



      • #4
        Family Finder tests chromosomes 1 thru 22 in addition to the x chromosome in the 23rd Chromosome.

        The 23rd Chromosome consists of an X and a Y in males.

        YDNA and Family finder tested different parts of your DNA. It sounds like you may be referring to a lab error in yDNA.


        • #5
          Thanks - I was confusing the two. This is a pretty steep learning curve for me and I appreciate the help from the experts!