I am wondering if anyone can tell me how firm the connection is between the Jefferson family of Richard and Samuel who moved to Maryland and Delaware in the late 1600s and early 1700s to the Thomas Jefferson who settled in Virginia and is President Jefferson's great-grandfather.
My son is doing a school science fair project looking at the Y DNA for his Thomas Jefferson family. The furthest away ancestor for him is Isaac Jefferson born in Delaware in 1792. We have not been able to definitively attach him to someone in the Delaware Jeffersons. However, the person who signed his marriage bann was Moses Ratledge (likely the younger Moses Ratledge) so that this links him to Richard Jefferson the IV in some way. In addition, Isaac's first son was named Richard and then Isaac and Richard Jefferson the IV dsappear form Delaware before the 1820 census. I know where Isaac went (to Millersburg KY).
It appears that Isaac is likely the son of Richard Jefferson IV from all the documentation I have been able to gather. My question is how sure is the connection between the Delaware/Maryland Jeffersons to the Virginia Jeffersons?