The only thing that is important to renumber for this discussion is that first cousins always share DNA.įull first cousins (cousins whose mother or father were full siblings to their cousin’s mother or father) It’s completely normal to have this wide range of shared DNA, since DNA is inherited randomly from each parent, there is no way to know or control which DNA is inherited. There will be more DNA shared by full first cousins than there is by half-full cousins. How much DNA should first cousins share?Įven though first cousins will always share DNA, the amount that they can share can very dramatically. It’s true that with every generation of descendants a little less DNA is inherited from the common ancestor (or pair of ancestors, like grandparents in the case of first cousins), but in the case of first cousins, so much DNA is shared by their parents, whether they were full or half-siblings, that it is statistically impossible for first cousins to share no DNA. Is it possible for first cousins to share no DNA?įirst cousins will always share DNA. I have not seen this issue on Family Tree DNA, so if you tested with that company, your match list is usually ready as soon as you get your results e-mail. If you just got your test results back today and you don’t see someone that you are expecting to see on your match list, I would recommend waiting for a few days before coming to any definite conclusions.
It can sometimes take a few days for your matches to “populate” on Ancestry. This particular paragraph addresses people who have tested with Ancestry DNA: This article discusses reasons what it means if a first cousin does not show up on your DNA match list. It can be disappointing or shocking to expect someone to be genetically related to you, but find out that they are not. More often than you might expect, people are surprised by their DNA results.