How Copying Errors Can Really Screw Up ThruLines

I want to illustrate how ThruLines is only as reliable as the family trees it's using, and how even if you appear to have a few DNA matches linking you both to the same ancestor, that doesn't make it accurate. As we know, it's common for the inexperienced genealogist (of which there are many) to blindly copy data from other trees without verifying it. All it takes is a handful of people copying the same error for ThruLines to make a wrong connection that might seem accurate because there's more than one DNA match.

My dad (JB, shown above) is a DNA match with two people, RJ and RH (you can ignore MM in the screenshot above, that's a legitimate connection I've verified). ThruLines suggests that they are both connected to my dad via his ancestor, Giovanni Biello. It does not include Giovanni's wife, so these are allegedly half cousins, but to my knowledge, Giovanni was only married once. I was open minded to the idea I might have missed another marriage, but then I noticed something else.

RJ and RH both descend from someone named Denizi Biello, b. Feb 1862 (according to the 1900 US Census), supposedly the son of my ancestor Giovanni Biello, b. 13 Jul 1847. This would mean Giovanni was only 14 when Denizi was born, which might be biologically possible but it's extremely unlikely. Men didn't marry until they were old enough to support a family, which they would not be at 14, and if they had children out of wedlock, the child was often left at the church as a foundling (meaning the father not identified). So something about this just didn't sound right to me.

Yet, 4 people had added Denizi as the son of this Giovanni to their tree. And in their defense, Denizi's death certificate does indeed say his father was Giovanni Biello and his mother Domenica Scioli.

Denizi's, or Dionisio Biello's civil birth record

Digging through the civil records of Monteroduni, Italy where both men were born, I found Denizi's birth records which finally held the answer. For starters, his original name was Dionisio Biello, and he was actually born several years before 1862, on February 2, 1856. But his parents names were correct: Giovanni Biello and Domenica Scioli. Only, Giovanni was not born anywhere near 1847. He was recorded as aged 38, which would make him born about 1818. It also said Giovanni was the son of the late Dionisio, whereas "my" Giovanni Biello was the son of Lorenzo.

So, two completely different men, as I suspected. I do not know who originally made the wrong assumption that Denizi was the son of "my" Giovanni but then 3 other people copied the error, ThruLines picked up on it and then found two people descended from Denizi. Since there were only 4 tree with the same error, I contacted all of them to let them know - hopefully they'll make the change and the incorrect ThruLines will disappear, but imagine if this error had been copied by more than 3 people! It probably wouldn't have been worth sending a message to each one since many likely wouldn't get the message or make the correction.

Granted, I have to admit that Monteroduni is a small town in rural Italy where there is a ton of endogamy and cousin marriages. I'm pretty sure everyone with ancestry in Monteroduni is related to everyone else there in some way, but it's still important to figure out the correct relationships whenever possible. Biello is actually a very rare surname and given that and the same location, our Biello lines probably intersect at some point, it's just a question of whether it's before or after civil records began in 1809. I'll certainly keep looking.