Hypotheses

 

Museum.ie 1930s Travel Poster.

Working through my second research question to determine the generation of connection on the Pennsylvania O'Briens who match my Dad's DNA results, I tried to use WATO on DNAPainter with the shared matches of matches who I can verify descend from James O'Brien and Mary Nolan. Of the eleven hypotheses it tested, a few jump out as possible.

Corrections soon (24 Oct 2024 update - I've completed the WATO tool incorrectly. I think the hypotheses I've posted are the right ones, but the percentages will change after I re-do the WATO chart. I spoke with an expert earlier today about this.)

1. John O'Brien (1793) had an unknown child between 1807-1829, and this child was the father of James O'Brien (1843). This hypothesis came back at 92% likely.

2. John O'Brien (1793) is the father of James O'Brien (1843). This came back at 7%. While so little is known of John O'Brien's time before he showed up in La Salle County, Illinois about 1850, I feel like this one is unlikely. It would mean John left James with a first wife or another family member and traveled West.

3. John O'Brien was the father of James O'Brien, with James as half-sibling to other children such as my La Salle County O'Briens. This is shown as possible at .24%

4. Another possibility, John O'Brien had an unknown sibling, who was the father of James O'Brien. This came back statistically possible, but less than .005%. WATO says "Data from additional matches could make a big difference."

So, it seems I'm looking for a mystery first marriage or first family for John O'Brien, before he made the move west. This hypothesis also shows that the Pennsylvania O'Brien matches either directly descend from him or a sibling of John's.