Read a Detailed Explanation of Results below
by our Coordinator: Marleen Van Horne

Explanation of DNA Results
by: Marleen Van Horne
(White Project Coordinator)

First, I want to thank Ian for starting this thread. It is for
questions like this that I started this mail list, and once I finish
trying to answer these questions, if anyone else has questions, please
ask them.
 
So, the question now is where to start. As I understand the question,
most of you who responded to Ian's message do not understand the
significance of the Family Group in which I have placed you.
 
The simple answer to that is that all of the men in a specific Family
Group have a common ancestor who lived within genealogical time, the
period for which we have documented records, the last 500 years. In
other words, all of the men within a Family Group are cousins to some
degree, and all men in a FG MUST have the same haplogroup, in this case,
R1b.
 
As has been commented, R1b is the most common male haplogroup in Western
Europe. Any man whose haplogroup begins R1b is theoretically a cousin
of any other man in that haplogroup. The question becomes how far back
in time did their common ancestor live---probably 40,000 years ago or
more. This time span is no good, if you are trying to find common
ancestors who lived in the last 500 years.
 
For those of you in haplogroup R1b1b2, the time span for a common
ancestor has been reduced to perhaps 20,000 years. The haplogroup of
each man tested is pretty much definitively identified in the first 12
markers FTDNA tests. There are a couple of male haplogroups, I and J,
that require additional testing, for certainty.
 
Over the years we have been doing genetic testing for genealogical
purposes, it has become apparent that tests at the 12 and 25 marker
level do not provide enough genetic information to definitively identify
family matches. For this reason, I prefer that members of my surname
projects test 67 markers, but realizing this could put a strain on the
pocketbook, I accept 37 markers.
 
The test results you receive show the number of times a specific four
character DNA pattern is repeated at a specific physical location on the
y chromosome. Those locations are called Single Tandem Repeats, or
STRs, and each has a name sort of like a street address. So, a 67
marker test tells you what your basic haplogroup is, and it gives you
the repeat values at each location on the y chromosome, that is tested.
For the most part, those repeat values are handed down from father to
son, occasionally with a few mutations, but over 67 markers, the number
of mutations should not exceed 7.
 
In the last few years, another type of mutation has been identified,
called Single Nucleotide Polymorphism, SNP, pronounced snip. In this
case, one of the four character DNA patterns has been interrupted by a
character being repeated twice within a pattern, for example, TCTA may
be TCTTA. All of the repeats at that location will read TCTA, but one
will be TCTTA. This is a SNP and it is an inheritable mutation. When
such a mutation is identified, it is give a name, such as R-L52, which
is one of the identifying SNPs for R1b1b2a1a.
 
This now brings us back to haplogroups. All members of a Family Group
MUST be in the same haplogroup. The fact that some individuals within
the FG may have a longer haplogroup designation only means they have
done advanced testing and extended their haplogroup. If all the other
FG members did advanced testing, they should have the same extended
haplogroup. The Family Group has been created on two sets of criteria,
common haplogroup, and less than seven mutations difference over 67 markers.
 
One common misconception I have encountered is that for two individuals
to be related genetically, they must match exactly. THIS IS NOT TRUE.
Each mutation is theoretically one generation of genetic distance. So
when two individuals differ by 2 mutations, genetic distance = 2, they
are VERY closely related. If the GD = 7, then their common ancestor is
farther back in time. For the most part, a GD of greater than 7 is
usually so far back in time, written records do not exist to prove the
connection.
 
Ok, so all of you who have been assigned to the same Family Group are
cousins to some degree, in a time frame that should be provable. If you
go to your MY FTDNA page and click on MATCHES, and scroll down to the 37
and 67 marker matches, you will find the names and e-mail addresses of
the people with the White surname who are in your FG. You then have to
get in touch with those people and try to figure out who your common
ancestor is. Do not bother with 12 or 25 marker matches.
 
If, on the other hand, you have no 37 or 67 marker matches, check your
preferences to see that your test results are being compared to the
entire FTDNA database. You may still have not matches, my White cousin
has no matches. Some of you who are being compared to the entire FTDNA
database, will find you have matches with other surnames. These should
not be ignored, depending on the GD you could be closely related
biologically. If you really want to research the genetic history of
your family, these matches should be looked into.
 
For more information on the R haplogroup, go to:
 
www.isogg.org/tree/ISOGG_HapgrpR.html
 
You will see each extension of the haplogroup, and the SNP mutations
that must be present to acquire the extension. Now don't run out and
order the advanced tests, if one of your group has been tested, you
share his extensions.
 
Also, on the lower right of the FTDNA homepage, is a tutorial you might
like to look at.
 
I hope this answers the question about the relevance of the Family
Groups, and I am sorry it is so long winded. I look forward to any more
question you may have.
 
Marleen Van Horne
White yDNA Project

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