Some new stuff:
Robert Carter7 Austin Jr. (Robert Carter6, Clyde Bernard5, Clisbe4, Clisbe3, Archibald2, Edward Riggs1)
Then there is your line:
Horace Lester7 Riggs III (Horace Lester6, Horace Lester5, John Woodson4, Samuel3, Clisby2, Edward Riggs1)
For all 3 of you the line above Capt. Ed Riggs(1720-1820) is the same:
Capt. Edward5Riggs (Samuel4, Edward3, Edward2, Edward1 (b.1590))
Clyde Bernard6 Austin III (Clyde Bernard5 Jr., Clyde Bernard4, Clisbe3, Clisbe2, Archibald1)
Robert Carter6 Austin Jr. (Robert Carter5, Clyde Bernard4, Clisbe3, Clisbe2, Archibald1)
William Luther7 Austin (William Brinks6, William Thompson5, Robert White4, William Thompson3, Clisbe2, Archibald1)
MRCA is Clisbe Sr.
John E6 Austin (E Woodrow5, Jacob E4, William3, Archibald II2, Archibald1)
MRCA is Archibald, himself.
Roy Burdine7 Riggs Jr. (Roy Burdine Sr.6,William E5, Henderson E4, Jesse Jr.3, Jesse Sr.2, Edward1)
MRCA is Edward Riggs
Roy and Robert have a 38 at marker 34. So we must conclude that Edward Riggs had the same. This is a mutation from the Ed Modal Sig. which has a 37 there.
Roy has a 17 at marker 33, which is a mutation from Ed Modal Sig. which has a 18, just like Robert. Therefore this mutation took place at Jesse Sr. or lower.
The mutation at marker 47 for Robert... he has a 9 there. Roy has a 10 like the Ed Modal Sig. Thus the mutation has to occur below Capt. Ed.... either in Archibald or in Clisbe Sr. We will know the answer to this when John E takes the test.
Horace Lester Riggs
(Horace Lester7 Riggs III, Horace Lester6, Horace Lester5, John Woodson4, Samuel3, Clisbe2 Riggs, Edward Riggs1)
Clay Austin
Clay7,Joseph C6, Joseph C5, William4, Archibald3, Archibald2, Ed Riggs1
Nancy Lynne7 Austin (Gerald Winston6,Clisbe Emerson Jr.5, Clisbe Emerson Sr.4, Archibald3, Clisbe2, Archibald1)
E Ray6 Austin (Luther5, Thaddeus4, Elanza3, James2, Nat1)
Ben Jr.6,Austin (Ben Sr.5, William4, Elanza3, James2, Nat1)