SUMMARY OF SNP (OCTOBER, 2013)
Classification of SNP: Near Private. L743 is the son of L1065. L1334 appears to be a brother of L743 but has not qualified for the ISOGG haplotree to date.
Estimated Breadth of SNP: 13 x 95 % (9 of 9) + 86 x 8 % (8 of 9) + 415 x 1 % (7 of 9) = 23 predicted positive submissions. All but one of the L743 positive submissions have been 9 of 9 matches to date and only one surname  Templeton. Only one of six submissions have tested positive at 8 of 9 matches and all fifteen submissions have tested negative at 7 of 9 matches. This implies L743 is a much more narrower breadth than most L21 YSNPs which usually test positive down to 70 % of the fingerprints.
The marker value 458 <= 16 appears to be YSNP defining mutation of the L743 fingerprint. At 8 of 9 matches, one of seven submissions have been tested with 458 <= 16 and this submission did test L743 positive. At 7 of 9 matches, three of ten submissions have been tested with 458 <= 16 but all three have tested L743 negative. This indicates that the mutation of 458 (17 to 16) is preL743 in origin and that having 458 <= 16 does not guarantee testing L743 positive (but greatly improves the probability of testing L743 positive).
Scope of Testing within Fingerprint: Above average  All thirteen out of thirteen known Templeton submissions (9 of 9 matches) have tested positive to date. All but one submission that has tested positive for L743 are Templeton submissions but one Preston submission tested L743 positive. However, only 21 of 501 known testing candidates have been tested at a 8 of 9 matche or 7 of 9 match.
Note that the number of known testing candidates increases as the fingerprint match decreases. This is not typical for most RL21 YSNPs. This trend suggests substantial overlap of L743 submissions with nonL743 submissions at high fingerprint matches. Additionally, most RL21 YSNPs test positive down to 70 % matches but L743 only tests positive at 100 % matches except for one 8 of 9 match.
Fingerprint
Match 
Percentage
Fingerprint
Match 
Known Number of
Testing Candidates 
Total
Tested 
Percent
Tested 
Total
Positive 
Percent
Positive 
9 of 9 
100 
13 
13 
100 
13 
100 
8 of 9 
89 
86 
6 
7.0 
1 
17 
7 of 9 
78 
415 
15 
3.6 
0 
0 
6 of 9 
67 
446 
12 
2.7 
0 
0 
5 of 9 
56 
412 
3 
0.7 
0 
0 
Summary of L743 testing
Dominant Surnames (positive): Templeton (13) and Preston (1).
Year that the SNP was discovered: September, 2011.
Source of SNP: FTDNA WTY  Templeton, 63127 (E6Q75).
Number of Positive Tests: Fourteen known.
Number of Negative Broad Tests (50 % or higher fingerprint matches): Around 35.
Number of Negative Tests within Fingerprint (70 % to 100 % matches): Twenty known.
Possible Untested Candidates (over 70 % match): Around 514 (over 95 % will be negative).
Pending Tests (within Fingerprint): None known.
ISOGG Status  Prove relationship of L743 to other L21 SNPs
L743 has met all ISOGG requirement and has been added to the ISOGG haplotree. At 67 markers, ISOGG requires a genetic diversity of 10 % (67 x 10 % = 7 mutations). Only one submission (270944 has higher genetic distance than five mutations).
SNP
Number 
FTDNA Submission Number
(or WTY GRC number) 
Project Name 
Test Results 

Prove ISOGG Father of L743 


L743+ 
63127 
L21 WTY 
L1065+ 

Prove L743 is not redundant with L1065 


L743 
48641 
L21 WTY 
L1065+ 

Eliminate possible fathers of L743 


L743+ 
63127 (optional) 
L21 WTY 
L1334 

Eliminate possible sons of L743 


L743 
48641 (optional) 
L21 WTY 
L1334+ 

Prove redundant SNPs of L743 


NA 
None known 
NA 
NA 

Prove SNPs that are sons of L743 


NA 
None known 
NA 
NA 

Prove 10 % Diversity (ISOGG) 


L743+ 
182451 
L21 Plus 
Base 
L743+ 
270944 
L21 Plus 
GD=10 
DNA FINGERPRINT & SIGNATURES
L743 Fingerprint (L21 Off Modal Mutations):
Markers 1 to 37: 391 <= 10, 3892 >= 30, 458 <= 16, YCAIIb >= 24, 456 <= 15 and 576 >= 19 (6 mutations).
Markers 38 to 67: 531 >= 12, 413a <=22 and 444 <= 11 (3 mutations).
L743 Signature (L21 Plus): 1335Sc743.
Markers 1 to 37: 391 <= 10, 389b >=17 (same as 3892 >= 30), 458 <= 16, 449 >= 30 (L21 MRCA), GATAH4 = 11 & 12 (H4 = 11 is L21 MRCA), YCAII = 19,24 (YCAIIa = 19 is L21 MRCA), 456 <= 16 and 576 >= 19 (7 mutations).
Markers 38 to 67: 531 >= 12, 413a <= 22 and 444 >=11 (3 mutations).
Testing Candidate Recommendations
1) All 9 of 9 matches (all Templeton submissions) have been tested L743 positive. Obviously, if new submissions are tested that match at 9 of 9 matches, they should also be tested as well (specially if the submission does not have the Templeton surname).
2) Since the testing candidates imply very significant overlap of L743 positive submissions with L743 negative submissions, the vast majority of submissions with 8 of 9 matches are lower will probably test L743 negative. However, it is very clear that 458 <= 16 is key to testing positive for L743. It is highly recommended that all 8 of 9 matches and 7 of 9 matches with 458 <= 16 should be tested. Four of seventeen of these submissions have been tested to date with one test result being L743 positive (25 % positive trend to date).
3) All other submissions with 8 of 9 matches or 7 of 9 matches are very speculative testing candidates (less than 5 % chance of testing positive). Only lower genetic distance submissions should be tested to enhance the chances of testing positive. Only genetic distance of nine or less is recommended for testing for these submissions. Since only 21 submissions out of 501 testing candidates have been tested to date, a handful of these submissions could test positive for L743.
