I just wanted to share this update on the Johnson line you cited. The lineage for Jacob Johnson, father of President Andrew Johnson, put forth by the late genealogist Hugh Buckner Johnston in the "North Carolina Genealogical Society Journal" in the early 1980s has been disproven by genetic testing. Jacob Johnson of Raleigh, NC and his probable father William Johnson of Mark's Creek District of Wake County were not descendants of Sill Johnson (d. 1763) of Johnston County, NC as suggested by Mr. Johnston's articles.
Silvanus "Sill" Johnson was born about 1696-1701 in Old Rappahannock (Essex) County, VA, the son of Henry Johnson (d. 1722) and his wife Elizabeth Muffett. Sill's family moved from Essex County to Lancaster County, VA in the 1710s, and his father Henry died there in 1722. Sill Johnson returned to Essex County by 1733, but sold his land there in 1738 and removed to Amelia (later Prince Edward) County, VA. Between 1750 and 1755, Sill Johnson migrated from Prince Edward County, VA to Johnston County, NC, where he acquired land on Swift Creek and White Oak Branch. He died in Johnston County in 1763. His children by his first marriage were Henry, William, Richard, and Sill, Jr. By his second marriage to Elizabeth (d. 1765, who was likely Elizabeth Carrell before marriage), he had two much younger sons Absalom and Benjamin Johnson.
Sill's son Richard Johnson died in Johnston County, NC in 1769. His widow Phereby remarried to Abner Sauls. She left a will in Johnston County, NC as "Phereby Sauls" devised in 1813 (proven 1821), which mentions her son William. This William was NOT identical with the William who owned land in the Mark's Creek District of Wake County believed to be the grandfather of President Andrew Johnson.
Genetic testing has been done for both the Sill Johnson line, as well as for the Jacob Johnson/President Andrew Johnson line. They are not a genetic match.
A direct descendant of President Johnson's brother William Johnson of Brazoria County, TX has been tested, as well as several descendants of Moses Johnson of Carter County, TN, alleged brother of Jacob Johnson. These lines were a match. Present genetic results at the Johnston/Johnston DNA surname project suggest that President Andrew Johnson and his father Jacob Johnson were descended from or genetically related to William Johnson (d. 1710) of Surry County, VA.