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Cake day: August 4th, 2023

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  • TootSweet@lemmy.worldtoGreentext@sh.itjust.worksAnon takes a DNA test
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    2 days ago

    AncestryDNA would absolutely give conclusive proof of either close blood relationship or lack thereof. In practice, it’s just as good as a paternity test.

    The only caveats I can think of are:

    • Both parent and (potential) child would have to get the test.
    • I guess if AncestryDNA just completely messed up and represented some random other person’s DNA as the parent’s or child’s, that would give false negatives.
    • Chimerism.
    • AncestryDNA might not be admissable in court.

    And of those, the first three are just as applicable to paternity tests as they are to AncestryDNA.





  • Well, just taking rs3746544 as an example, the SNPedia page has this chart at the bottom of the right-hand column:

    An image showing frequency of different genotypes for rs3746544 across several different specific populations

    Notice there are only three colors there. Just eyeballing it, it seems most people have either the AA or AC genotype, with CC making up a pretty small minority.

    But the fact that TT doesn’t register at all on that chart and otherwise just isn’t mentioned anywhere on the page at all makes me think I must be missing something. (Which wouldn’t surprise me. It is genetics, after all. There are definitely tons of rabbit holes to fall down in that area of study.)

    Someone else mentioned in a comment that it must be a mutation. (I assume they mean a mutation that happened recently enough – few enough steps up my ancestral lineage – that sources like SNPedia have just never seen it before.) And if I only had one example, and if it was only one allele and not on both strands, I might be inclined to agree.But I have… a lot of examples of that. Just doing some napkin math, I got a rate of about 16.5% “impossible” or undocumented genotypes. There’s no way that for 16.5% of well-known/well-studied SNPs I happen to have a completely undocumented double-strand mutation, right?

    (Just to explain my methodology for coming up with that 16.5% figure, I took all the SNP’s listed on these two pages: one and two, and found all SNPs for which a) genotypes are documented on the page and b) I’ve got a genotype for that SNP in at least one of the data files I got from either 23andme or AncestryDNA (or both). That got me 139 examples. Of those, 23 of my SNP’s didn’t match any of the genotypes listed on the Eupedia pages. For a rate of 23/139=0.1654676…~=16.5% .)

    (Side note: oddly of the 23 “mismatch” examples I mentioned, my genotype doesn’t have a single allele in common with the documented possible alleles for the SNP. For example, I don’t have any AT’s where the documented alleles are AA, AC, and CC. My genes either match the documented alleles or have no alleles in common with the documented genotypes. Which seems even stranger.)

    (Another side note: if 23andme and AncestryDNA didn’t agree on the genotype, I’d be inclined to think it was an error on one of their parts, but I haven’t found any specific SNPs where they disagree with each other yet.)

    So, to get back to your main question:

    Does “possible” mean “normal values for x% of the population?”

    By “impossible”, I mean I haven’t been able to find any documentation of anyone else having the same genotype as I have for that particular SNP. And that makes me feel like I’m almost definitely not understanding something.

    I kindof doubt that the genotypes I have for these mismatches are actually exceedingly rare or completely undocumented or anything. I think probably someone knows exactly why I’d be seeing the results I’m seeing (and it probably isn’t tons of obscure mutations or anything.) So, honestly, “impossible” is probably bad wording.




  • You can take my terminal when you can pry it from my cold, dead, hands.

    Any one-liner you put together, you can re-run trivially. You can rerun it with modifications trivially. You can wrap it in a for loop that runs it with different parameters trivially. You can stick it in a file and make a reusable Bash script. It’s far easier to show someone else how you did it (just copy/paste the text of your terminal session) than dozens of screenshots of a point-and-click adventure (and not in a good way) GUI app. Bash commands are easier over SSH than GUI apps over RDP or VNC or whatever. You can’t script a GUI app.

    I seriously find myself wondering why someone would use a GUI for something they can do with a terminal. Learning curve is the only reason I can think of.

    I frequently find myself creating tools that let me do with a terminal what I formerly could only do with a GUI tool.






  • My mother is constantly googling things and reading me the AI overview. And I know LLMs make shit up all the time, and I don’t want AI hallucinations to infect my brain and slowly fuck up my worldview. So I always have to drop everything and go confirm the claims from the AI overview. And I’ve caught plenty of inaccuracies and hallucinations. (One I remember: she googled for when the East Wing of the White House was originally built and the AI overview told her the year of a major renovation, claiming it was the year it was built, but it had been built much earlier.)