Siblings and DNA

3 Culbert siblings: Vicky, Ian, and Phil. Let's imagine that all three of them took the DNA test. They should all share the same DNA, right? Wrong. Read on...

Here's a question I'm often asked...

"Why should I take a DNA test? My brother (or sister) already took the test. Won't our results be identical?"

The answer is no. The DNA of your sibling may be similar to yours but it's far from identical.  

I'll give you a personal example. Both my sister and I took the Ancestry DNA test. We have a 3rd cousin (let's call her Phaedra) who also took the test. Phaedra's son also took the test. And Phaedra's granddaughter took the test too.

So that's three generations of Phaedra's family who are related to us, who took the test. 

I thought, "All three of these people are related to us in exactly the same way. So my sister should share DNA with them and I should share DNA with them too, right?"

My sister shares DNA with all three of them. Bingo! That makes perfect sense because my sister is related to all three of them. 

So far, so good. But wait...

I'm related to all three of these people too. However, I share DNA with NONE of them!

How is it possible that sibling DNA is so different? You all know that I'm not a scientist...

... so it's better if you click here for an answer. 

If you don't have time to read the whole article, scroll down to the section that asks, "Why it is good for more than one sibling to do an Ancestry DNA test?"

 

And for a more detailed explanation, click on this article, Do Siblings Have the Same DNA?"

Note: Thanks to my sister taking the DNA test, I found Phaedra (and Phaedra's son and granddaughter) and as a result, I was able to find out more details about our family history. My sister's DNA results have been a goldmine for me so far as family history research is concerned. If she hadn't taken the test, I wouldn't be making the discoveries that I've been making. And for those of you who've already taken the test? You may not realize it but your DNA results have been helping me too. Thank you.