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DNA Testing and Results
What is going to be discussed in this post and other post is not meant to be argumentative on my part or any criticism toward any individual or company, but rather just an attempt to explain some things about DNA testing results and the interpertation of those results.
So let's begin.
Participant------------1 and 4
Marker
1----393---------------13---13
2----390---------------24---24
3----19/394------------14---14
4----391---------------10---11
5----385a--------------12---12
6----385b--------------14---14
7----426---------------12---12
8----388---------------12---12
9----439---------------13---13
10---389-1-------------13---13
11---392---------------13---13
12---389-2-------------29---29
13---458---------------16---16
14---459a---------------8---10
15---459b--------------10---10
16---455---------------11---11
17---454---------------11---11
18---447---------------25---25
19---437---------------14---15
20---448---------------21---19
21---449---------------31---30
22---464a--------------13---15
23---464b--------------15---17
24---464c--------------16---17
25---464d--------------16---17
The above are the results with two individuals with the same identical surname. Initially participant 1 took a 12 marker test while participant 4 took the 25 marker test.
Comparing the results participant 1 was an 11/12 match with participant 4. Which has two specific explanations about the comparison of the 11/12 match:
First Explanation:
Details on the various assumptions used in computing TMRCA
Current version: 27 Jan 2002
Walsh, Bruce, 2001. Estimating the time to MRCA for the Y chromosone or mtDNA for a pair of individuals, Genetics 158, 897--912.
'Concluding remarks'
If you are interested in whether a particular person is a relative, a simple 12 marker test can exclude the possibility of being relatives (i.e., if there are two or more mismatches). If there is zero or one mismatch, that person is a reasonably close relative.
Second Explanation:
'Interpreting Genetic Distance' by Family Tree DNA
Distance 1 Relatedness: Possibly Related
Explanation: You share the same surname (or a variant) with another male and you mismatch by only one 'point' on only
one marker. For most closely related or same surnamed individuals, the mismatch markers are either DYS
439 or DYS 385a, 385b, 389-1 and 389-2. To ensure that the match is authentic you should refine to the
25 marker test.
To say the least the two different explanations of the comparison of an 11/12 match is confusing, one saying 'you are related' and the other saying 'possibly related'.
And with an oral history and paperwork that did indicate that participant 1 ancestor and participant 4 ancestor did have a common ancestor the 11/12 match by DNA testing did seem to be on that same course for a common ancestor between 1 and 4.
However, participant 1 upgraded to a 25 marker test and the results, to say the least, did not come back favorable for a common ancestor between 1 and 4.
Comparing the 25 marker test results on can see the genetic match is 16/25. Which is nothing less than 'not related to this person'.
If the 25 marker test would have been the starting test for both participants then any possibilities about being related or unrelated would have been more certain, maybe not conclusive, but a least more certain.
I will discuss more on this in another post.
Richard
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