This is a mistake I’ve been laboring under, in part because of mislabeling on the part of Ancestry on the 1840 census (they give Jr the 1789 birth date without any particular reason), and in part from not taking a good look at the best resource for separating the two.
It turns out that both men are buried in the same cemetery, and the right virtual look just about gives both away. But you need to make that look.
“Our” Charles is born in 1789, is married to Rebecca Williams in 1811 and passes in 1857.
“Little” Charlie is born in 1792, is married to Holly Hill (Polly Hill) in 1814 and passes in 1876.
I began to wonder when in the 1830 US census, Charles Marwen turned out to be Charles Myers Sr and the ages of children made more sense to be “our” Charles than the “Jr” down the page. The fact is they’ve got Charles Jr’s ages wrong in the 1840 census, which didn’t help, but you have to plan on bad data mixed in with these old stuff.
Marriage records, despite the bad birth dates and the misspelled Holly Hill, also made it worthwhile to find some double checks.
This doesn’t affect the DNA analysis much. William Jr and Charles Sr are thought to be brothers, because Charles Sr is made administrator of William’s estate. This makes Charles about equally distant genetically from William Sr as his brother. If we go with the theory that William Jr fathered Charles Jr, Barney and all, then William Jr is much older than Charles, at least 15 years older.
When did the families head south to TN? The earliest date I’ve seen is buried in Ancestry data on John Myers, William Sr’s son. This entry in a Ancestry tree says 1790. One account of the Girdner’s entry into TN, along with a Myers brother in law, happens in 1792. They have to be in Tennessee by 1795, because Barney says he was born then (1850 census). So Charles Sr was on the move sometime between the ages of one and six, and Charles Jr could have been born on the move.
Finding a living descendant of “Little” Charlie or Barnabas could help our narrative immensely.
Update: more specific on the Williams.