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Saturday, June 9, 2018

DNA Test Showing Mother and Father's Genes in a Match (Phasing) With GedMatch

Nadene Goldfoot                                         
My children have had a familyfinder DNA test with Family Tree DNA  as well as myself. The test results have been also transferred to GedMatch.com.  There are more tools there to use. 

I've just discovered a tool at GedMatch that I hadn't tried before, and it's called PHASING.  I find that one of my children have a match with someone, and I can find out through phasing what segments came from me or their father.  It's great.  I've seen (recombination) occur where a segment from me can be in the middle of their father's longer segment on one of our 23 chromosomes.  I've also seen segments from their maternal and paternal side and segments that are unknown.  Evidently not all can be identified.

What I've done is change the given 7 cMs on the tool to a 1cMs to catch any under 7cMs.  They do not appear to be random numbers to me, as I have 2 children and can triangulate even these teeny segments between 3 people; my 2 children and the 3rd party they happen to match. 

I can see that 2 very small matches happen to come from the maternal side. 
#10 chromosome shows 2.5cMs of which 1.9 came from the maternal side. 
#  3 chromosome shows 1.8 cMs of which  1.3 came from the maternal side.
It was a very big surprise to find that both of us parents matched this person.  It's not a common thing to happen. 

We all have 23 chromosomes.  They are numbered, with the numbers on the left side of the chart below.  A segment of DNA has a start and and end, just like measuring a candy bar's length, only it's measured in centimorgans, not inches.  I ignore the SNPs.  I'm not concerned with that in phasing.

Notice that #3 and #10 's origins are from the child's maternal side, found with the phasing tool. 

ChrStart LocationEnd LocationCentimorgans (cM)SNPs
11,876,37918,645,55838.14,724
1188,809,934193,835,0063.6864
28,6743,778,2586.01,149
223,392,13738,674,02616.94,001
2113,275,385128,834,68515.13,229
2168,111,926169,744,5123.1576
311,105,34230,861,15825.45,356
378,677,50984,921,1841.8829
3136,606,065140,176,1611.8547
3163,745,440199,167,82055.57,265
461,5664,218,0345.6726
693,946,897106,930,90710.32,377
6147,057,473152,505,1819.91,684
770,819,12875,761,9954.2555
88,745,38010,159,7251.6510
1025,864,71163,890,83729.67,818
1072,905,81476,660,1912.5714
1086,056,820103,078,67316.44,455
1111,432,40374,203,50061.714,070
1261,8803,586,6469.41,029
1220,528,86821,454,4111.6563
12124,351,087131,507,61926.12,681
1559,887,79870,422,88315.22,419
1572,276,26075,654,7371.7512
1576,495,98791,365,77223.43,963
1610,264,64116,872,60611.41,712
1664,455,38867,182,7541.3603
1681,737,64688,668,97820.53,023
1829,646,32168,648,23847.59,936
1914,504,49916,010,0332.4582
2044,034,70062,374,27447.25,908
2234,988,80149,528,62534.94,477
Here is the match from the child's paternal side.  

ChrStart LocationEnd LocationCentimorgans (cM)SNPs
11,943,92618,595,07837.74,652
28,6743,771,9406.01,138
223,572,52838,674,02616.83,915
2113,275,385128,743,70514.93,191
311,105,34230,711,55525.25,263
3165,498,710199,167,82054.97,006
461,5664,218,0345.6723
693,946,897106,930,90710.32,357
6147,368,327152,485,0829.71,596
1025,864,71163,738,34929.57,716
1086,519,932102,954,50215.94,285
1111,482,00074,096,81161.513,912
1261,8803,586,6469.41,024
12124,351,087131,338,90725.92,648
1559,887,79870,422,88315.22,402
1577,050,87691,365,77222.53,829
1610,264,64116,867,13811.31,694
1681,789,55488,668,97820.32,962
1829,661,52468,648,23847.59,854
1914,546,93416,010,0332.3564
2044,034,70062,374,27447.25,876
2234,988,80149,528,62534.94,433

Here is the report from the maternal side.  There was a match, a surprise but very very small.  



ChrStart LocationEnd LocationCentimorgans (cM)SNPs
379,489,20984,921,1841.3689
1073,201,07576,660,1911.9544

I'd suggest that parents have their children tested, too.  It's always best to start with the oldest person in a family, though, and then you can always get the rest tested later.  The lucky children will benefit because then they will see what genes came from which parents.  Someday, we may even find out what these genes have created in us, such as:  intelligence, diseases, coloring, etc. 

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