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Alexander Blair & Elizabeth Cochrane

The Alexander Blair - Elizabeth Cochrane line is one of the most researched BSGR lines. 27 members (14 of them active) believe they descend from Alexander and Elizabeth.

Known children of Alexander and Elizabeth: John Blair b.1756 m. Eleanor Hamilton; Thomas Blair b.1757 m. Eleanor Evans; Alexander Blair b.1762-63 m. Sarah Ralston; Elizabeth Blair b.1759 never married; William Blair b.1760 m. Catherine Evans; Mary Blair b.30 Oct 1765 m. James H. Manara; Margaret "Peggy" Blair b.1765 m. Robert Wallace; Benjamin Blair b.1767 m. Elizabeth ___ and maybe, Archibald Blair and Samuel Blair

This line may finally be resolved. We now have the results of four participants who believe they descend from this line. The results of the first three participants (#3948, #7636, and #9332) indicated that these three participants COULD NOT share a common ancestor. The results of the fourth participant (#20208) and other genealogical information I now have, provides a much clearer picture of this line. 

The tables below show the number of markers that do not match and the total mutations between each of the participants.
Marker Mismatches                      Total Mutations 
   3948   7636   9332  20208      3948   7636   9332  20208
 3948    19 8 8    3948    30 10 10
 7636  19   16 16    7636  30   26 26
 9332  8 16   0    9332  10 26   0
20208 8 16 0     20208 10 26 0  

The actual marker values for each participant are shown in the table below.


Marker		 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
  DYS#
Part
ID#		 3
9
3		 3
9
0		 1
9
*		 3
9
1		 3
8
5
a		 3
8
5
b		 4
2
6		 3
8
8		 4
3
9		 3
8
9
i		 3
9
2		 3
8
9
ii		 4
5
8		 4
5
9
a		 4
5
9
b		 4
5
4		 4
5
5		 4
4
7		 4
3
7		 4
4
8		 4
4
9		 4
6
4
a		 4
6
4
b		 4
6
4
c		 4
6
4
d
3948 13 24 14 11 11 14 12 12 12 13 13 29 17 09 10 11 11 24 15 19 30 15 15 17 17
7636 12 24 13 10 17 18 11 12 12 14 11 31 15 09 09 11 11 26 14 20 31 14 16 16 16
9332 12 24 14 11 11 15 12 12 12 13 13 29 15 10 10 11 11 26 15 19 30 14 15 18 18
20208 12 24 14 11 11 15 12 12 12 13 13 29 15 10 10 11 11 26 15 19 30 14 15 18 18

Participant #3948 descends from John Blair and Susannah Ewing. On his pedigree chart he states "The dispute continues about whether or not John Blair b:1756 is the son of this Alexander Blair. I hope DNA will be of assistance here." According to the "Blair Society for Genealogical Research Members’ Lineages (1983 - 2003)" this John Blair is NOT a son of Alexander. It appears quite obvious from the DNA test results that this John Blair CANNOT be the son of Alexander.

The discrepancies between #7636 and #9332 / #20208 have been explained to me and will not be discussed here.

The diagram below show the pedigrees of the two participants who are connected to each other, and most probably to Alexander and Elizabeth.

 

Because #9332 and #20208 both descend from William Blair and Catherine Evans the DNA test results do not provide conclusive evidence that they descend from Alexander. Matching DNA test results are required from a participant who descends from Alexander through another son. Based on the DNA test results AND the known paper trail it is reasonable to assume that both are descendants of William and that their identical 25 marker test result is the "DNA signature" of William Blair.

#9332 and #20208 belong to Group 1 indicating a very high probability that they descend from the Blair of Blair and connect to several other BSGR lines.