Many American Johnsons claim descent from the family written about in 1972 by Lorrand V. Johnson in
"The Ancestry of William and John Johnson."
An Account of the Connections of the Family of Johnston of Caskieben, and of that Ilk, of the Garioch, Aberdeenshire, Scotland"
As with most published family histories there were errors and omissions in the publication. His assumptions have been passed down and around so much that they appear to be facts. He also influenced William Wade Hinshaw's Quaker publications.
A number of major changes were reflected in the 1988 edition with the Terrell Family Intermarriages.
The Johnson Y-DNA project was originally created to see if some of the claimed lines of descent were in fact related.
The R1b-Family ZZE (Olive) Group has some of the original test subjects and others that match them.The Olive Group page at Jeffrey A. Bockman - Olive Group (google.com) has a further discussion of the research issues and descendant reports for the current family groups of the members based upon DNA and research. FamilyFinder results will also be used.
See Results (above) for more detail.
2021 DNA tests have proven that there is not a direct male connection between the Caskieben Clan and Lorand's claimed lines.