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Jonathan Long
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Kennedy Family Connections
Autosomal DNA evidence suggests that our family may be connected to a group of Kennedy descendants, specially, from four lineages: James  Kennedy born between 1770 and 1775 and wife Elizabeth--see http://freepages.genealogy.rootsweb.ancestry.com/~bart/Canad...
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Getting extra out of 23andme and AncestryDNA tests: Y SNPs
After learning from the ISOGG website (http://www.isogg.org/wiki/Autosomal_DNA_testing_comparison_chart) that both 23andme and AncestryDNA tests
include some Y SNPs, I did some investigations to see what we might get out of
those results. 23andme Haplogroup...
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Using Genetic Genealogy to Break through Brick Walls in Your Family Tree
Getting Started in Genetic Genealogy Genetic genealogy is the process of using DNA tests to determine how people are related through shared DNA (by “blood”). To better understand this rapidly evolving field, the International Society of Genetic Genealogy ( ...
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Long-lost George long rediscovered
A DNA cousin recently noted a shared match among number of our Long cousins. This new match descends from a George Long from Ohio. I suspect that this George is the "long-lost" member of our James Long-Mary Bearmore family from Greene County PA and Guernsey...
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How strong of an x DNA match would you consider to indicate common ancestry at the fifth cousin level, through pathways that mostly alternate male to female? My apologies to folks who are not accustomed to the level of detail in this post, but I hope it will be a useful example of how to use x DNA and Gedmatch when the autosomal DNA is stretched thin....

Here is my case, with the participants made anonymous because none of the kits involved are my own.
One individual A1, a male, has an autosomal match on chromosome 10 with a third cousin of mine, A2, a female, and the same segment is shared with her mother, M3. and her mother's brother. A first cousin of mine has a 5 cM autosomal segment in common with A1, but myself and other cousins do not have any matching segments that large. However, x DNA also suggests an x connection between A1, A2, M3, and A4 (another female who is a second cousin. The x DNA seems to really narrow the possible connections to only a few lines, so I think this evidence is pretty consistent with a 5th cousin relationship back to a common ancestor. Would others agree with that basic interpretation of the x DNA?

Comparing Kit M3 and A1

Minimum threshold size to be included in total = 700 SNPs
Mismatch-bunching Limit = 350 SNPs
Noise Reduction Threshold = 0.85
Minimum segment cM to be included in total = 7.0 cM


Chr Start Location End Location Centimorgans (cM) SNPs
10 14,554,067 24,635,989 12.4 2,833

Largest segment = 12.4 cM
Total of segments > 7 cM = 12.4 cM
Estimated number of generations to MRCA = 5.1

GEDmatch.Com X-DNA Comparison

Comparing Kit A1(M) and A4(F)

Minimum threshold size to be included in total = 200 SNPs
Mismatch-bunching Limit = 100 SNPs
Noise Reduction Threshold = 0.90
Minimum segment cM to be included in total = 3.0 cM


Chr Start Location End Location Centimorgans (cM) SNPs
X 20,421,541 23,344,846 6.9 598
X 35,406,292 37,905,232 3.1 237
X 93,074,688 99,735,673 7.4 665
X 111,966,868 114,376,586 4.1 203
X 116,351,129 119,698,292 6.0 481
X 142,285,593 143,552,719 3.3 202
X 147,612,820 149,433,373 4.2 206

Largest segment = 7.4 cM
Total of segments > 3 cM = 35.0 cM Actual.
Sex-Adjusted total of segments = 26.3 cM Equivalent.


Comparing Kit A1(M) and A2(F)

Minimum threshold size to be included in total = 200 SNPs
Mismatch-bunching Limit = 100 SNPs
Noise Reduction Threshold = 0.90
Minimum segment cM to be included in total = 3.0 cM


Chr Start Location End Location Centimorgans (cM) SNPs
X 18,287,242 22,801,683 7.2 667
X 35,051,166 37,697,265 3.1 226
X 84,971,716 87,895,463 3.1 375
X 117,546,480 119,698,292 4.9 315
X 147,134,022 150,037,358 7.4 383

Largest segment = 7.4 cM
Total of segments > 3 cM = 25.7 cM Actual.
Sex-Adjusted total of segments = 19.3 cM Equivalent.
GEDmatch.Com X-DNA Comparison

Comparing Kit A1(M) and M3(F)

Minimum threshold size to be included in total = 200 SNPs
Mismatch-bunching Limit = 100 SNPs
Noise Reduction Threshold = 0.95
Minimum segment cM to be included in total = 3.0 cM


Chr Start Location End Location Centimorgans (cM) SNPs
X 18,784,847 22,225,424 3.9 416
X 22,235,479 23,163,230 4.5 290
X 45,251,074 47,372,436 4.0 284
X 142,761,163 144,235,735 3.7 240
X 147,075,004 149,294,747 4.8 235

Largest segment = 4.8 cM
Total of segments > 3 cM = 20.9 cM Actual.
Sex-Adjusted total of segments = 15.7 cM Equivalent.
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