Jacob and Emily Sandidge

John Calvin Sandidge and Emily (McKenzie) Sandidge, photograph ca. 1900, Scott County, VA
 



Analysis of CTS2457 SNP

SUMMARY OF SNP (June, 2013)

 

Classification of SNP: Small branch (near private) - son of DF13.

Estimated Breadth of SNP (speculative estimate of positive submissions) = Less than twenty predicted positive submissions at 67 markers. General testing for DF13** submissions is not recommended - only reasonable matches of the CTS2457 fingerprint should test (around 40 known testing candidates). With known higher matching testing candidates, CTS2457 should pass the new ISOGG genetic distance requirement unless further testing reveal that CTS2457 is very genetically isolated.

Scope of Testing within Fingerprint (> 70 %): two tested (with 67 markers tested).

Dominant Surnames: Lunney (2) - but many surnames should test positive.

Year that SNPs were discovered: April, 2013 (from Nat Geo test).

Source of SNP: Nat Geo test - Lunney, FTDNA ID 159824, Y-Search ID Q4A8X.

Number of Negative Broad Tests: Under 40 tests (most are from Nat Geo tests).

Number of Negative Tests within Fingerprint (above 70 % match): None in fingerprint.

Possible Candidates (70 % match): Around 40.

Pending Tests (within Fingerprint): Probably several Nat Geo tests.

 

ANALYSIS OF FINGERPRINT MARKERS

 

All seven markers in the CTS2457 YSNP appear to be pre-CTS2457 in origin. This will result in a significant amount of overlap of submissions with same fingerprint matches testing both positive and negative. The higher the genetic distance within a fingerprint match, the more likely to test negative. This also could result in a few submissions below 70 % testing positive - although the vast majority will test negative. 534 >= 16 appears to have a major backwards mutation to 534 = 15 for many higher fingerprint matches.

 

TRENDS OF TESTING CANDIDATES

Note that the number of known testing candidates does not appear to be typical for a L21 SNP where the number of testing candidates declines down as it approaches 70 % matches, remains low just above and below 70 % matches and then sees a sharp rise as testing candidates approaches 50 % matches. The curve for CTS2457 immediately rises in numbers as the fingerprint matches drops. This suggests two possible scenarios: 1) the current CTS2457 fingerprint could need some major fine tuning with additional testing; 2) CTS2457 is not genetically isolated and could have a lot of overlap of testing results resulting in testing both positive and negative at the same fingerprint match. Below shows the trends of testing candidates for the CT2457 fingerprint:

 

Fingerprint
Match
L193-M
Percentage
Fingerprint
Match
Known Number of Testing Candidates

Total
Tested

Percent
Tested

Total
Positive
Percent
Positive
Percent
Predicted
Positive
Number
Predicted
Positive
7 of 7
100
3
2
66
2
100
90
2.7
6 of 7
86
6
0
0
NA
NA
80
4.8
5 of 7
71
29
0
0
NA
NA
30
8.7
4 of 7
57
100+
1
<1.0
0
0
0
0
Total              
16.2

 

 

ISOGG Status - Prove relationship of CTS2457 to other L21 SNPs

 

Requirements of proving CTS2457 position on the ISOGG haplotree have not been met to date. Several relationship tests remain to be verified. With additional testing, the genetic diversity requiremnt appears very likely to qualify for inclusion on the ISOGG haplotree. However, this will be one of the smallest scope DF13 sons to qualify (smaller scope than L96, L144 and L371).

 

SNP
Number
FTDNA Submission Number
(or WTY GRC number)

Project Name

Test Results
Prove ISOGG father of CTS2457
CTS2457+
159824
L21 Plus
DF13+
Prove CTS2457 is not redundant of father
CTS2457-
N55408
L21 Plus
DF13-
Eliminate possible fathers of CTS2457
CTS2457+
Needs testing
NA
DF49-
CTS2457+
159824
Nat Geo
L513-
CTS2457+
159824
Nat Geo
Z255-
CTS2457+
159824
Nat Geo
Z253-
CTS2457+
159824
Nat Geo
DF21-
CTS2457+
159824
L21 Plus
DF41-
CTS2457+
Needs testing
NA
L1335-
CTS2457+
159824 (optional)
Nat Geo
CTS4466-
CTS2457+
159823
L21 Plus
L96-
CTS2457+
159823
L21 Plus
L144-
CTS2457+
Needs testing (optional)
NA
Z251-
CTS2457+
159824
Nat Geo
L371-
CTS2457+
159824 (optional)
Nat Geo
L679-
Eliminate possible sons of CTS2457
CTS2457-
216031
L21 Plus
DF49+
CTS2457-
Needs testing
NA
L513+
CTS2457-
Needs testing
NA
Z255+
CTS2457-
Needs testing
NA
Z253+
CTS2457-
20437
WTY
DF21+
CTS2457-
Needs testing
NA
DF41+
CTS2457-
19706
WTY
L1335+
CTS2457-
Needs testing (optional)
NA
CTS4466+
CTS2457-
176268
Nat Geo
L96+
CTS2457-
130084
Nat Geo
L144+
CTS2457-
Needs testing (optional)
NA
Z251+
CTS2457-
N84982
Nat Geo
L371+
CTS2457-
170191 (optional)
Nat Geo
L679+
Prove redundant SNPs of CTS2457
NA
None known
NA
NA
Prove SNPs that are sons of CTS2457
NA
None known
NA
NA
Prove 10 % Diversity requirement
CTS2457+
159824
L21 Plus
Base
CTS2457+
159823
L21 Plus
GD = 6

 

 

DNA FINGERPRINTS

L21 Off Modal Mutations:

Markers 1 to 37: 391 <= 10, 385b >= 15 and 392 >= 14 (3 mutations).

Markers 38 to 67: 557 >= 17, 534 >= 16, 520 >= 21 and 617 >= 13 (4 mutations).

 

DNA Signature (L21 Project): z6171314

Markers 1 to 37: 391 = 10, 392 >= 14 and 449 >= 30 (3 mutations).

Markers 38 to 67: 557 >= 17, 520 = 21 and 617 >= 13 (3 mutations).

 

Testing Candidate Recommendations

 

For a detailed list of good testing candidates, see the spreadsheet of testing candidates which can be found in the CTS2457 link in the DNA Results pull down menu. Here are the priorities for testing:

1) Almost all fingerprint matches with 6 of 7 matches and 7 of 7 matches will probably test positive. One or two submissions with 6 of 7 matches and higher genetic distance could test negative. It is recommended that all 6 of 7 matches and higher be tested due to the uncertainty of the current CTS2457 fingerprint and the nature of the testing candidates curve which implies overlapping testing results.

2) All the 5 of 7 matches should be tested. These tests will help clarify the order of mutations and there will be many negative tests in the lower half of the spreadsheet as the genetic distance increases. It is highly recommended that all 5 of 7 testing candidates be tested for CTS2457.

3) It is very doubtful that many of the 4 of 7 matches will test positive, however, one or two 4 of 7 matches could test positive. Testing 4 of 7 matches would be very speculative in nature (so low that they were not listed in the spreadsheet). It is believed that as more testing candidates are tested will result in fingerprint adjustments where lower fingerprint matches will no longer ever test positive.