Why No Match ?
Why Don’t I Have a Better DNA match with Cousin Ron EAST?
from a Points East article by Chris East .
I became the 29th person to take a DNA test as part of the EAST DNA project which was set up by our former chairman Lionel East in 2004. Lionel handed over the project to Ron East on standing down at the AGM in October 2010.
Ron East, my second cousin, had already undergone his 37-marker DNA Y-chromosome test some before. Ron and I have a paper trail relationship to our most recent common ancestor (MRCA), Henry Ashler EAST, born 1842 in Burgh le Marsh Lincolnshire. Henry is Ron‟s great grandfather and my great (x2) grandfather. Hence all being well, I expected to have an exact match with Ron, or at the most one marker difference in the 37 analysed in the test. However, the recent results of my Y-DNA37 test show that we have four markers in 37 which are different.
As Ron says in his article "it is all a matter of probability - nothing is certain". Two men with an identical 37-marker match have a 90% chance of having a common MRCA in the last four generations and a 95% chance in the last 7 generations. If 35 out of 37 match, there is a 95% chance of an MRCA within 14 generations. Our apparent common ancestor Henry EAST was a mere 3-4 generations ago, yet we have 4 differences in our 37 markers, of one step on each marker. Our DNA testing company FamilyTreeDNA rates Ron and I as 'probably related' and places us in the same rare Haplogroup of R1a1a, meaning that at least our ancestors very many generations ago came from the same geographical area before migration.
So what about these four differences: they are caused by possible errors (mutations) in the DNA each time the highly complex DNA is copied and passed to the next generation. Mutations do occur; otherwise everybody would have the same DNA which would not be helpful. The mutations are a very rare event, apparently occurring for each marker once every 250-500 generations. Based on these four marker mismatches and current genetic marker mutation rate theory, Ron says that there is a probability of only 3.7% that we have an MRCA in the last four generations!
So what do we do now? We could test others in our family to see where mutation occurred, but that would be expensive. Some researchers are casting doubt on the accuracy of these mutation rate probabilities, saying that the model could be more complex than anticipated and that mutations actually occur more frequently than expected. My feeling, even as a statistician, is that Ron and I ARE related and should not take further action for the moment.
Then along comes Kevin ....................
Kevin can trace his family line back to Lincolnshire too but there is no paper trail at the moment that shows a link with the ancestors of Chris and Ron.
However Kevin's Y-DNA test showed his nearest DNA match with 32/37 markers was with Ron East.
This is not considered a close enough match to prove a clear familial link but it gets more interesting when you consider that Kevin is also a member of the rare haplogroup R1a1a.
As Ron says in his article on DNA testing one of the highest frequencies of the Haplogroup R1a1 is found in Norway, Sweden and Iceland which it is believed to have been the reason why this haplogroup spread across Europe by migrations of Vikings, which would account for its existence in the British Isles.
The Anglo-Saxons invaded Enland in the fifth Century. Saxon rule extended from 449 to 1066, but during that period they were subject to many attacks by the Danes.
Skegness was a favourite landing place for the Viking fleets with large numbers of Danes & Norwegians invading the county of Lincoln from 870. They plundered villages and towns, massacred the inhabitants and established many Danish settlements. Scandinavian settlers followed the raiders into the areas under Danish law. The existence of so many Danish and Scandinavian elements in the place-names in this district is still strong evidence of these occupations.
So Ron, Chris and Kevin :
all have matching markers within 32 to 33 of each other
all belong to the rare R1a1a haplogroup
all three can trace their ancestors to parishes in Lincolnshire about 50 miles apart where their haplogroup would have been established by invasions from the European area where it incidence is highest.
There is always the possibility that their DNA has undergone a higher than normal mutation rate which could also account for the difference in the DNA markers.
On paper as yet there is not proven link but the above facts suggest that they are most likely related to each further back in their ancestry than we can currently trace. . . .
"it is all a matter of probability but nothing is certain".