View Full Version : Will full siblings all have the same resuts?

03-23-2017, 09:36 PM
I'm sure this has been asked before.. I did a search but could not find what I was looking for..

I have 4 siblings.. all from the same parents.. My results should all match theirs I would expect.. Is that correct? So.. if one of us does the Ancestry DNA.. test that result will be the same for all of us..

03-23-2017, 11:16 PM
You would expect the ethnicity predictions to be fairly similar, but not exactly the same, unless there are identical twins involved.

We inherit about 50% of our DNA from each parent, but the chunks of DNA you get from each are random. You might have inherited some bits of DNA that your siblings did not.

I wrote "about 50%" on the line above because, if you are a male, you inherit a little bit less than 50% of DNA from your father, since the y chromosome is smaller than the "normal" x chromosome that women inherit from their fathers.

But sure, testing one of the siblings should be enough to give a clue on how the others would score.

03-24-2017, 03:59 PM
My full sister and I have both tested at FTDNA; while there are some similarities there are some differences, both in the small percentages as well as the larger inheritances. She shows far more of the Scandinavian than I do, for instance, and while my mother and I both show 1% Central Asian (of all things) she does not. We have known British ancestors; I show 3% for that, while nothing shows up for her.

03-24-2017, 04:03 PM
no, they can vary. i'll post my mom's and aunt's as an example

03-25-2017, 04:13 PM
Thank you.. sort of what I expected..

03-25-2017, 04:28 PM
Even identical triplets can get different results according to this segment (https://www.youtube.com/watch?v=qyfWZZ7uPuE) of Inside Edition. Since the DNA of identical triplets has essentially no differences the problem is either with the tests not getting the same result in every run, which means the raw data files are different, or the calculators behave differently in each run or it can be a combination of both. So the differences in siblings in DNA tests isn't due just to a difference in DNA.