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. 

Chr	Start Location	End Location	Centimorgans (cM)	SNPs
1	1,876,379	18,645,558	38.1	4,724
1	188,809,934	193,835,006	3.6	864
2	8,674	3,778,258	6.0	1,149
2	23,392,137	38,674,026	16.9	4,001
2	113,275,385	128,834,685	15.1	3,229
2	168,111,926	169,744,512	3.1	576
3	11,105,342	30,861,158	25.4	5,356
3	78,677,509	84,921,184	1.8	829
3	136,606,065	140,176,161	1.8	547
3	163,745,440	199,167,820	55.5	7,265
4	61,566	4,218,034	5.6	726
6	93,946,897	106,930,907	10.3	2,377
6	147,057,473	152,505,181	9.9	1,684
7	70,819,128	75,761,995	4.2	555
8	8,745,380	10,159,725	1.6	510
10	25,864,711	63,890,837	29.6	7,818
10	72,905,814	76,660,191	2.5	714
10	86,056,820	103,078,673	16.4	4,455
11	11,432,403	74,203,500	61.7	14,070
12	61,880	3,586,646	9.4	1,029
12	20,528,868	21,454,411	1.6	563
12	124,351,087	131,507,619	26.1	2,681
15	59,887,798	70,422,883	15.2	2,419
15	72,276,260	75,654,737	1.7	512
15	76,495,987	91,365,772	23.4	3,963
16	10,264,641	16,872,606	11.4	1,712
16	64,455,388	67,182,754	1.3	603
16	81,737,646	88,668,978	20.5	3,023
18	29,646,321	68,648,238	47.5	9,936
19	14,504,499	16,010,033	2.4	582
20	44,034,700	62,374,274	47.2	5,908
22	34,988,801	49,528,625	34.9	4,477

Here is the match from the child's paternal side.  

Chr	Start Location	End Location	Centimorgans (cM)	SNPs
1	1,943,926	18,595,078	37.7	4,652
2	8,674	3,771,940	6.0	1,138
2	23,572,528	38,674,026	16.8	3,915
2	113,275,385	128,743,705	14.9	3,191
3	11,105,342	30,711,555	25.2	5,263
3	165,498,710	199,167,820	54.9	7,006
4	61,566	4,218,034	5.6	723
6	93,946,897	106,930,907	10.3	2,357
6	147,368,327	152,485,082	9.7	1,596
10	25,864,711	63,738,349	29.5	7,716
10	86,519,932	102,954,502	15.9	4,285
11	11,482,000	74,096,811	61.5	13,912
12	61,880	3,586,646	9.4	1,024
12	124,351,087	131,338,907	25.9	2,648
15	59,887,798	70,422,883	15.2	2,402
15	77,050,876	91,365,772	22.5	3,829
16	10,264,641	16,867,138	11.3	1,694
16	81,789,554	88,668,978	20.3	2,962
18	29,661,524	68,648,238	47.5	9,854
19	14,546,934	16,010,033	2.3	564
20	44,034,700	62,374,274	47.2	5,876
22	34,988,801	49,528,625	34.9	4,433

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

Chr	Start Location	End Location	Centimorgans (cM)	SNPs
3	79,489,209	84,921,184	1.3	689
10	73,201,075	76,660,191	1.9	544

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.