Copying Trees

They say that imitation is the sincerest form of flattery. That may be true, but it can also be the fastest way to error in family history.

While most would recoil from the thought of copying another’s algebra test or forging their friend’s signature, copying information from an online pedigree chart is a fairly common genealogical practice. Now, we could spend all day talking about the moral implications of that practice, but we won’t.

What I do want to address is the impact this practice has on your genetic genealogy experience at AncestryDNA.  We have received a few inquiries about this topic here at Genealogy Gems, and I chatted with a fellow genealogist about this at a recent conference.   

The practice of pedigree copying factors most heavily in the DNA Circles and New Ancestor Discoveries (NAD) at Ancestry.com. You will remember from our previous conversations that these tools are like parties that your DNA has secured you tickets to attend. Each of these parties is “hosted” by one of your ancestors.  In the case of the DNA circle this is a documented ancestor, and it is a presumed ancestor in the case of a NAD. Let’s focus on the DNA circle, where you have a documented connection to the person listed. Sometimes we catch ourselves declaring that our membership in the DNA circle “proves” our connection to the party host.

But we must be careful.

Because it does not.

“Proves” is too strong of a word. All your membership in the DNA circle can really tell you is that you have a genetic connection to those marked with the orange line. Those with the grey connecting lines have a DNA connection to some of the circle members, but not to you. Placing the name of an ancestor on the cover of this gathering does not guarantee that the named person is your common ancestor. It is just a suggestion; a hint.

Think about this for just a second. Let’s say that Joan does a bit of research and decides that her immigrant ancestor’s father is Marcus Reese, born in 1823 in Wales. She adds this to her pedigree chart. She sees on a census record that he had four children, one of whom shared the name of her ancestor, William, and adds those to her chart as well.

Months later, Charlotte is researching her Mary Reese and sees Mary listed on Joan’s pedigree chart as the child of Marcus. She knows Mary’s father was born in Wales, and adds Marcus to her pedigree chart telling herself that she will go back later and double check.

And so on.

After a while, we have 7 people all connected back through Marcus and his four children and they all, independently decided to get their DNA tested through Ancestry.com.

Ancestry sees their shared DNA and that they have all listed Marcus Reese as their common ancestor. So they create a DNA circle for the seven of them, with Marcus Reese at the head.

But what if Joan, the initial researcher who placed Marcus on her tree, was wrong? What if these seven people are not actually related through Marcus, but his brother? Or his cousin? Or even someone totally unrelated to him?

Ancestry did not look at the number of cited sources or the myriad of other genealogical possibilities about how these seven individuals could all be related to each other. It saw a genetic connection, and a genealogical hypothesis, and it presented them to you in the form of a DNA circle.

Here are the facts: The genetic evidence supports a common ancestor for these 7 people.  The DNA can also give us an estimate about how many generations back we would expect to find that common ancestor. But, that ancestor does not have to be named Marcus Reese.  A name is a genealogical piece of information and is a completely separate type of data than the genetic information. Theoretically, the two, the name and the genetics, go together. You can become more certain as you gather the traditional genealogical evidence that you would in any other case. As your documentation mounts, so will your confidence, with the DNA acting like an invitation to keep searching for further evidence of your connection.

Originally Published at www.genealogygems.com