My sister, my only sibling and I have literally no physical traits in common. Whatever trait I inherited from one parent she inherited from the other. We're thinking of using one of those genome analysis services to learn information about our mysterious geographical ancestral origins.

We're wondering if, despite our differences in appearance, if only one of us submitted our genome for analysis, the geographic origin results would still be accurate for the other. Because our parents may both have diverse lineages, the answer might not be so cut and dried.

Understand, please, that we are not so much looking to find out the general "where" of our origins as we are to have each of us know what our individual genetic heritage is.


2 Answers 2


If you are siblings, then, outside the Y chromosome (if you are a man, otherwise, you both only have X chromosomes), the results should be very similar. There might be some slight variations of course but it is unlikely to come out as important.

If you are not siblings (e.g. you might be half-sibling if your mother is hiding an affair; sorry for suggesting this possibility but that's no so unusual), then the results might well be quite different.

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    $\begingroup$ Hello! This question was deemed worth of an answer, so why not upvote it? Vote early, vote often to encourage new users and keep the community alive! $\endgroup$ Oct 11, 2018 at 22:19
  • $\begingroup$ @LinuxBlanket I was not 100% sure that the question would be considered worth of an answer. It has happen to me a few times in the past to be criticized of answering questions that aren't worth it. But thanks for pointing this link to me and everyone else! $\endgroup$
    – Remi.b
    Oct 11, 2018 at 22:23
  • $\begingroup$ @LinuxBlanket Btw, why haven't you upvote then? $\endgroup$
    – Remi.b
    Oct 11, 2018 at 22:24
  • $\begingroup$ Even if it's not considered worth of an answer by the community, your opinion still counts and can be expressed not only by answering, but also by voting. With that upvote, you gave the OP the chance and maybe the will to participate more. Thanks, and remember to vote early and vote often! :) $\endgroup$ Oct 11, 2018 at 22:28
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    $\begingroup$ Ok! I'll make sure to apply this logic. Let's vote early and let's vote often! Thanks $\endgroup$
    – Remi.b
    Oct 12, 2018 at 1:07

You should be aware that DNA tests can't give highly localized "geographic origin" information. Genes spread around, so exact locations can't really be pinned down. Many gene variants can be confidently assigned to continental areas (Africa, Asia, Europe), but it begins to get hazier as smaller areas are considered. For example, many British Isles variants can be distinguished from other European variants, but French versus German genes really can't reliably be separated for the most part. You might care to see what other people think of their results, for example by looking at Reddit posts about 23andMe results.

Most siblings will get pretty similar origins results. If each of the parents individually has several very distinct origins, then siblings can have somewhat more divergent origin results depending on the randomness of inheritance. The only way to know what you two each have is for both of you to get tests. You should consider that if, in actuality, you two are half-siblings, or are not closely related (as e.g., one or both of you were adopted), the results will show that.


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