I began to notice a subtle pattern emerge when looking at cousin matches presented by Ancestry’s ThruLines for mine and other families I have access to view. It stands to reason that any technology that relies on algorithms and other people’s trees would be vulnerable to errors.
I kept asking myself how many cousin matches is enough to accept that an ancestor is correct? Notice I’m not saying prove an ancestor is correct, but accept that an ancestor is correct. The only lineage that can be proven with DNA alone is parent and child. For all other lineage relationships DNA can only support other data. This is especially true when we start working with 4th and 5th great-grandparents.
The time finally came to look at the Lewis line. I’m not overly familiar with this line and haven’t done a ton of research so am looking for clues where to look in the ThruLines results for me and my uncle.
The Lewis surname first appears with my 3rd great-grandmother Martha G Lewis on my father’s maternal line.
In addition there is evidence of a DNA match through her son James Hamilton Cox. Records support these connections so I feel comfortable with them. Records also support her parents being Richard Lewis and Catherine Jewell. ThruLines for Richard Lewis look like this:
Polly, Louisa B and Serenico A are all provable siblings for my Martha G. so these results are easy to accept.
Thus far the only thing I’ve seen suggesting the father of Richard Lewis is one anecdote online stating his name was Thomas Lewis. Here’s what ThruLines proposes for a Thomas Lewis:
I’ve been through all these trees and found nothing that looks like proof of this relationship. I think Martha and Richard’s matches clearly illustrate that I inherited what I can label Lewis DNA. Some Lewis family somewhere contributed DNA. Do I accept that the Thomas Lewis I’m being offered is correct? Given only these results my answer is not yet. What I see here are several people descended from some Lewis ancestor who may or may not be this man.
This is where my uncle’s results come into play. He has another generation of results to view that I don’t have. On these trees the wife/mother that is offered is Mary Bandy. Neither of us have any matches to her, but what he has are matches to the man being offered as her father: Richard Bandy. Here are six of the ten siblings shown as offspring of a Richard Bandy:
It would appear that my uncle has both Lewis and Bandy DNA. I saw that a daughter of a Richard Bandy is named in his Will (not shown here) as “Mary Lewis wife of Thomas Lewis”. I’m not offering it as proof because I haven’t done enough work to satisfy myself that these are the people who belong to that document. For now I’m willing to add a Thomas Lewis and Mary Bandy as parents of Richard Lewis to my tree to facilitate further research. So while Richard Bandy might be the father of Mary Bandy, who is the father of Thomas Lewis in the ThruLines universe?
The Honorable Thomas Lewis. Pretty cool guy…hung with George Washington, is in the DAR database as a Patriot…sweet. Right? Love me some Patriots. While perusing the DAR database I noticed something odd. There are more than 150 women who have him as a Patriot and not one of them joined using the child Thomas. The first person who joined using this individual was in 1891! There have been ample opportunities for someone to join using the son Thomas. Why hasn’t anyone done it?
Welp. I found a book on ancestry.com: Genealogies of the Lewis and kindred families, edited by John Meriwether McAllister and Lura Boulton Tandy, published by the E.W. Stephens Publishing Company of Columbia, Missouri printed in 1906. Here is an excerpt from page 180:
Sorry, y’all, but Thomas Lewis is not the son of the Honorable Thomas Lewis. But, but, the DNA. This is why I keep asking how much is enough? My uncle shares DNA with four of the proven children of this Thomas Lewis.
Here’s the thing: based on the above mentioned book, the Lewis family was quite large. That Thomas Lewis had brothers who had a boatload of children, too. That DNA is bound to show up in a lot of people, some of whom can readily trace their lineage to the Honorable Thomas Lewis (whose brothers were more famous than him, by the way). For all we know our Thomas Lewis could be a by-blow of any one of those brothers, or even Thomas himself. What we can’t do is prove where that DNA originates. We can guess it comes from that family though, and that is intriguing and might be a fun project for someone more skillful than me.
I’ve seen this in other people’s ThruLines, too. Questionable matches that don’t necessarily belong to the people they are assigned. I think it’s wise to guard against being lulled into complacently accepting matches simply because multiple descendants of siblings appear in our results. This is especially true for the 4th/5th great-grandparents. DNA is a good deal more a finding aid than proof.