World Families Network
Interpreting
Results
Last Update 1 Oct 2006
Take a
look at
FTDNA's Tutorial Page - with many
links:
We all share common ancestors - the question is how recently. Is it
“recent”, since the advent of surnames, long ago or very long ago
-
I
think in these time frames
-
Within several hundred years - a shared recent common ancestor or
“RCA”
-
Since the advent of surnames (c1100). I call this common ancestor
since the advent of surnames a “CAS”
-
In the range of 1000s of years. This is defined by men sharing the
same "Haplogroup"
(which can go to 10-20,000 years ago)
-
In the range of 10s of 1000s of years. This is shown by men who do
not share a Haplogroup
-
Matches are evaluated in terms of markers which have the same result.
-
Based on a large database, a Haplogroup assignment can be made for
most results - based on an assessment of the first 12 markers.
-
Sometimes,
a SNP (pronounced "snip" test is required to identify the
Haplogroup.
-
Haplogroup
assignments at FTDNA are color coded
-
Green -
SNP tested
-
Red -
estimated by FTDNA, based on matches (or near matches) to
other results which were SNP tested
-
Black -
other estimates of the Haplogroup
-
For those
interested in exploring this a little further, Whit Athey has
developed a tool to estimate your haplogroup.
Click Here .
-
If a sufficient quantity of markers match, then we can confirm a RCA
or CAS
-
Once we have at least two matches at 25 markers or more, we (World
Families Network) declare
a "Lineage" - which is a group of men descending from a Common
Ancestor
-
As we get more results, we can often define the exact result of
the Common Ancestor at every marker. We call this the
"Ancestral Haplotype"
-
As we get more results, the paper trails give us insight into
when and where this Common Ancestor may have lived.
-
Within a Lineage, the non-matching markers may give us more
information
-
Typically, the mismatches will be only one count - except on the
markers which mutate the fastest (464 and CDY)
-
We call the mismatches "Mutations"
-
If the mutation has no match - it is simply a mutation (for now)
-
If the mutation is matched by another result, we likely have an
indication of a branch recent common ancestor (BRCA) who also
descends from the RCA, but lived more recently and is shared by
the two men with the matching mutation
-
Statistical analysis is disappointingly vague, as the mutations are
pretty random, but we can still make some useful generalities - as
long as we don't try to become too precise in our interpretation.
I think of these statistical results as a "fuzzy" answer.
-
One approach to this
analysis is "Time to Most Recent Common Ancestor" or tMRCA" which can be
reported at the 50% probability (this can very misleading)
-
Family Tree DNA's
FTDNATiP calculator makes a similar calculation and reports the
probabilities for each 4 generations (which they call 100 years.
Because this approach gives a range of answers, it is a more appropriate
form of answer - but is not "satisfying" in simplicity)
On
12 markers
-
A 12/12 match of the men of the same surname usually indicates a RCA - or possibly an earlier CAS (or both)
-
Many 12/12 matches of men with differing surnames will fall apart at
25 markers - as the 12/12 resolution isn't regularly sufficient to
discern relationships across differing surnames
-
A few 12/12 matches of men of the same surname also "fall apart" at 25 markers, but most maintain a
“Match” (see the Russell example below)
-
A number of 11/12 matches and most 10/12 matches fall apart at 25
markers - indicating no RCA or CAS
-
I prefer not to have to assess relationships based on 12 marker
results and won't "call" a Lineage until at least two men
"match" at
25 markers
On 25 markers:
-
Matches of 23/25, 24/25 & 25/25 indicate a RCA and CAS. In
shorthand - a match of 23/25 or better is even called a "Match"
-
Matches of 22/25 or even 21/25 may indicate a CAS - but probably not
a RCA. This situation requires more markers to have clear insight
-
Matches lower than 21/25 typically indicate that there is no CAS
-
When in doubt
about the interpretation at 25 markers, upgrades to 37 markers
provide additional clarity
On 37 markers
-
Matches of 33/37 and better indicate a RCA and CAS. These are the
ones typically called a "Match"
-
Matches of 29/37 and higher indicate a moderate to higher
probability of CAS, increasing in probability as the match gets
tighter
-
Some families mutate faster than others, providing additional
insight as the number of results in a Lineage increases
On matches at markers with mutations, we can begin identifying the BRCAs.
This is when yDNA testing begins to directly correlate with paper
trails.
-
Matches
indicating BRCA are a close match to the Ancestral Haplotype, but
share a mutation that is different.
-
It is possible
for more than one BRCA to show on a result (see the Barton example
below)
-
It is in the context of the BRCA that a 37 marker test for someone whose
paper trail already puts them in the Lineage can potentially benefit
themselves and others of the Lineage, as they begin to help in defining the branch
structure.
------------------------------------------------------------------------------------------------
Here is a sample from the Russell family, which shows men who were
12/12 (or 10/12 and 11/12)
|
|
Real Example |
* |
3 |
3 |
1 |
3 |
3 |
3 |
4 |
3 |
4 |
3 |
3 |
3 |
|
|
H |
9 |
9 |
9 |
9 |
8 |
8 |
2 |
8 |
3 |
8 |
9 |
8 |
|
|
a |
3 |
0 |
|
1 |
5 |
5 |
6 |
8 |
9 |
9 |
2 |
9 |
|
|
p |
|
|
|
|
a |
b |
|
|
|
| |
|
| |
|
|
l |
|
|
|
|
|
|
|
|
|
1 |
|
2 |
|
|
o |
|
|
|
|
|
|
|
|
|
|
|
|
|
Russell Lineage I |
R1b |
13 |
23 |
14 |
11 |
11 |
14 |
12 |
12 |
11 |
13 |
13 |
29 |
|
R-2 |
John L Russell, b 1833 |
R1b |
13 |
23 |
14 |
11 |
11 |
14 |
12 |
12 |
11 |
13 |
13 |
29 |
|
R-23 |
JD Russell |
R1b |
13 |
23 |
14 |
11 |
11 |
14 |
12 |
12 |
11 |
13 |
13 |
29 |
|
R-25 |
CE Russell |
R1b |
13 |
23 |
14 |
11 |
11 |
14 |
12 |
12 |
11 |
13 |
13 |
29 |
|
R-3 |
ES Russell |
R1b |
13 |
23 |
15 |
11 |
11 |
14 |
12 |
12 |
11 |
13 |
13 |
29 |
-
R-2, R-23 and R-25 are all 12/12 to
each other and to the Lineage I Haplotype
-
R-3 is 11/12 to the others and to the
Lineage I Haplotype
-
It appears that all 4 men share a
RCA.
Then, all men upgrade
|
|
Real Example |
* |
3 |
3 |
1 |
3 |
3 |
3 |
4 |
3 |
4 |
3 |
3 |
3 |
4 |
4 |
4 |
4 |
4 |
4 |
4 |
4 |
4 |
4 |
4 |
4 |
4 |
4 |
G |
Y |
Y |
4 |
6 |
5 |
5 |
C |
C |
4 |
4 |
|
|
H |
9 |
9 |
9 |
9 |
8 |
8 |
2 |
8 |
3 |
8 |
9 |
8 |
5 |
5 |
5 |
5 |
5 |
4 |
3 |
4 |
4 |
6 |
6 |
6 |
6 |
6 |
A |
C |
C |
5 |
0 |
7 |
7 |
D |
D |
4 |
3 |
|
|
a |
3 |
0 |
|
1 |
5 |
5 |
6 |
8 |
9 |
9 |
2 |
9 |
8 |
9 |
9 |
5 |
4 |
7 |
7 |
8 |
9 |
4 |
4 |
4 |
4 |
0 |
T |
A |
A |
6 |
7 |
6 |
|