The Shirley Association has been a member of the Guild of One-Name Studies since 1988
  Markers
DNA Project

 

 

 

   
 

How to Understand Test Results from a 12 Marker Test

Exact Match

An exact match using a 12 marker test indicates a 99% probability of having the same ancestor. However, the ancestor may have existed well before the Shirley surname was clearly fixed (as much as 2500 years ago). A 25 marker test will shorten the existence of that shared ancestor to within the surname’s existence.

Off by 1 Marker (12 marker test)

These results suggest mathematically that there is a 50% likelihood that the two families share the same direct male ancestor [Shirley?] in 37 generations or less. There is a 90% probability that the two families share the same direct male ancestor in 85 generations or less. There is a 95% likelihood that the two families share the same direct male ancestor in 103 generations or less. And 95% of the mathematical results fall in between generations 5 and 121.

Off by 2 Markers (12 marker test)

These results suggest mathematically that there is a 50% likelihood that the two families share the same direct male ancestor [Shirley?] in 61 generations or less. There is a 90% probability that the two families share the same direct male ancestor in 122 generations or less. There is a 95% likelihood that the two families share the same direct male ancestor in 144 generations or less. And 95% of the mathematical results fall in between generations 14 and 165.

Info on DNA Markers # 6 and # 9

Some markers change or mutate at a faster rate than others. While that actual 'faster rate' has not yet been definitively calculated, not all markers should be treated the same for evaluation purposes.

The DNA markers #6 and #9 have shown a faster mutation rate (i.e. change numbers) then the average, and therefore these markers are very helpful at splitting lineages into sub sets, or branches, within your family tree.

Explained another way, if you match exactly on all of the markers except for one or a few of the markers we have determined mutate more quickly, then despite the mutation this mismatch only slightly decreases the probability of two people in your surname group who match 11/12 or even 23/25 of not sharing a recent common ancestor.

 

Info on DNA Markers # 10 and # 12

When comparing two sets of results, if the mutations at each of the two markers 10 and 12 are off by the same number of steps, and the mutations move in the same direction, meaning ascending or descending, then we only count these two markers together as ONE mutation, not TWO.

   
How to Understand Test Results from a 25 Marker Test

Distance

Relatedness
Explanation
0 Related Your perfect 25/25 match means you share a common male ancestor with a person who shares your surname (or variant). These two facts clearly demonstrate relatedness.
1 Related 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 same surnamed individuals, the mismatch markers are usually either DYS 439 or DYS 385 A, 385 B, and 389-1 from our first panel of 12 markers, and from the second panel: DYS #'s 458 459a 459b 449, 464 a-d, which have shown themselves to move most rapidly. The probability of a close relationship is very high.
2 Probably Related You share the same surname (or a variant) with another male and you mismatch by two 'point' from the 25 markers we tested. For most closely related and same surnamed individuals, the mismatch markers are either DYS 439 or DYS 385 A, 385 B and 389-1 from our first panel of 12 markers, and from the second panel: DYS #'s 458 459 a 459b 449, 464 a-d, which have shown themselves to move most rapidly. The probability of a close relationship is good, however the results show mutations, and therefore more time between the two same surnamed person. Continued testing should find males near or perhaps identical to this group member.
3 Probably Not Related You share the same surname (or a variant) but are off by 3 'points' or 3 locations on the 25 markers tested. If enough time has passed it is possible that these two group members are distantly related family members. However that would nearly require that each line had passed a seperate mutation and one would have experienced 2! The only way to confirm or deny is to test additional family lines and find where the mutation took place. Expressed another way, assume your score puts you at 3 on the clock. Assume the person 3 from you is at the 9 position. Only by further testing can you find the person in between each of you...this in 'betweener' becomes essential for you to find, and in their absence the possibility of a match exists, but further evidence should be pursued.
4 Not Related 21/25 is too far off to be considered related. Unlikely but vaguely possible that the rule for ONLY Possible related applies. It is important to determine what set of result most typifies 'most' members of the group you are 'close' to matching. You may be 21/25 with an individual, but 23/25 with the center (most common) of the group, and your potential relatedness to him is through the center of the group.
5 Not Related 20/25 You are not related and the odds greatly favor that you have not shared a common male ancestor with this person in excess of 2,000 years
6 Not Related 19/25 You are not related and the odds greatly favor that you have not shared a common male ancestor with this person in excess of 5,000 years
>6 Not Related You are totally unrelated to this person.
   


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