On the face of it, a Y-DNA haplotype appears to be just a string of
meaningless numbers — and without a lineage, it is. For a haplotype
to be useful, we need to understand what the values for the markers mean
when used in combination with paper genealogy. To simplify understanding
them, I place these marker values into four categories:
1. Modal Values. These values are the most
common ones for the entire haplogroup subclade; and, because they are the
most common values to have, having them is literally unremarkable.
2. Signature Markers. These are non-modal marker
values shared by everyone in a family. They consistently and, in
combination, uniquely distinguish a family. Presumably, these
are the mutations possessed by the family's progenitor within "genealogical
time." In contrast, sharing the haplogroup modal values with a family
is of virtually no significance beyond the fact that you're related somewhere
back in time — as we all are if you go back far enough.
3. Private Markers. These markers are unique to one
test subject. The mutation has happened in the individual's descent
from the family progenitor, but we don't know in which generation.
As more cousins are tested, private markers will turn into branch markers,
unless the mutation occurred in the test individual, himself. Because
the latter can be the case, it is not irrelevant to test a brother, father,
or first cousin. Anyone with a private marker should test cousins
(i.e., 1st cousin, 2nd cousin, 3rd cousin, etc.) until the location
of the mutation is determined.
4. Branch Markers. These are marker values shared
by two or more members of a family, but not the entire family, in other
words, by a branch of the family. Once someone has proven their membership
in the family by possessing its signature markers, the branch markers become
highly important because these markers most likely represent a shared common
ancestor more recent than the family's progenitor. (In some cases,
a shared value on a volatile, fast mutating marker may mean the mutation
happened more than once in the family; paper genealogy and the testing
of cousins can determine which is the case.)
To demonstrate the above, I've taken an example from a cohesive lineage
group in the GIBSON
project as shown in the table below (thank you, Valentine Van Zee,
Gibson Project Administrator, for your assistance and cooperation).
We are all related to one degree or another, so it would be superfluous
for me to say all the individuals in the table are "related." The
question is whether or not they are related in genealogical time,
that is, since the adoption of surnames and the keeping of records for
common citizens. For most of us, that means being related within
12 to 15 generations or within about 350-450 years. |
| One thing obvious from the chart is that everyone needs to upgrade
to 67 markers to really understand what is going on. The GIBSONs
who have not tested 67 markers will have to remain in an "unassigned" group
until they upgrade. I have found the need for 67 markers to be the
case for Haplogroup R1b in all my projects. If a haplotype is rare,
you can sometimes get away with fewer markers, but not in R1b. Haplogroup
R1b is the most common haplogroup in western Europe, reaching a frequency
of 70-80% in the British Isles (please see distribution
map). |
Modal Values
The first row in the table below is the modal haplotype for Haplogroup
R1b, which is highlighted in cyan (light blue). Like most individuals,
the test subjects match their haplogroup's modal haplotype at most markers.
Being R1b and matching a modal value for R1b should be considered of minimal
genealogical significance. It simply supports that you are a member
of a large group originating thousands of years ago. The genealogically
significant values are those that differ from the R1b modals, so
please ignore all the values highlighted in cyan and consider the sea
of blue simply background noise. My use of the R1b modal should
not be taken as implying that it is the ancetral haplotype for either the
haplogroup or the family, nor that the genetic distance from it can be
used to estimate the distance in time from the haplogroup's common ancestor.
There are many paths from the haplogroup's ancestor to its descendants,
none of them direct (i.e., without innumerable twists, turns, and
reversals — on each and every marker). With the aid of paper genealogy,
the most we can hope to unravel is the last ten to twenty generations. |
Signature Markers
Ignoring the markers highlighted in cyan, we are struck by the agreement
of most of the differences, that is, the six columns highlighted in the
muted orange color I've selected for the GIBSON family, plus two columns
highlighted in bright green. These are this GIBSON family's signature
markers. |
Private Markers
Scattered around the table are cells highlighted in bright yellow.
These are private mutations, ones acquired by these individuals in their
descent from the family's progenitor. When testing 67 markers, you
can statistically expect one mutation event to occur about every
seven generations, and experience has shown (empirical evidence demonstrates)
that the number of mutation events typically ranges from 0 to 3 in an individual's
descent from a common ancestor
in genealogical time. (This
number can be higher in families with deep roots, such as some Scottish
clans with paper genealogies tracing back into the 13th Century.) |
Branch Markers
I've highlighted the branch markers in purple. The mutation at
DYS413a represents a major division in this GIBSON family. If everyone's
pedigree is carried back far enough, the lines will presumably converge
on the ancestor in whom this mutation occurred. |
There are three other cases where this GIBSON family has individuals
sharing what would otherwise be a "private" mutation (i.e., a value
that is neither modal for the haplogroup nor signature for the family).
In one case, it's clear that it's a true branch mutation, that is,
a case of two individuals sharing the same common ancestor, one more recent
than the family progenitor. The second case may represent the same
situation, but we don't know for certain because we don't know their lineages.
In the third case, it appears we have an instance of the same mutation
happening twice on a very volatile marker.
| • The certain branch marker is shared by G-6 and GX-1 who have
a value of 14 at DYS392 when everyone else is 13 at that marker.
A check of their pedigrees suggests John (G-6) is the great-grandfather
of Gideon (GX-1). It appears a value of 14 at DYS392 will identify
descendants of John, with the inference that no one else in the table descends
from him. |
| • The possible branch marker is shared by G-113 and G-11 who
have a value of 19 at DYS570 when nearly everyone else is 18 at that markers.
We don't have a lineage for G-113, so we don't know where or if they have
a recent connection. DYS570 is a volatile marker, so the mutation
could have happened independently. |
| • The other case is the value of 41 at CDYb for G-20 and G-23.
CDY is volatile multi-copy marker; and, because G-20 and G-23 differ
at DYS413a, I believe this is a case of the same mutation happening twice
on CDYb, making each of these a private marker, not a branch marker.
Note that these two individuals cannot be placed on a logically branching
tree unless either the CDYb mutation happened twice or the DYS413a mutation
happened numerous times. As the former is far more probable, I'm
assuming that is the case here. |
|
| As it happens, this family has remarkably few Branch and Private mutations
in the 38-67 marker panel. I have a similar situation in one family
in my CARRICO project, but in other projects this panel has as much variability
as the other panels. My point is to not allow the lack of mutations
here discourage you from making 67 markers the standard for your project.
Sooner or later it will pay off. |
| Two individuals, namely the HURST and the COLLINS, appear to have NPEs
in their lineages, that is, they are really GIBSONs. Ironically,
each of these matches 67/67 to the GIBSON modal haplotype (and, no, I don't
see any particular significance to that fact). |
| It appears the JUSTICE individuals are related to these GIBSONs, though
it's unclear whether it's through an NPE
or simply that their connection is prior to surname adoption. In
a cladogram, their haplotype would be the most ancestral one, which is
the reason they are placed at the top of the table. The ancestral
haplotype is followed by the addition of the mutations at DYS449 and CDYa
(bright green table cells), then followed by the mutation at DYS413a (dark
purple table cells), then followed by the "private" mutations (bright yellow
table cells). If you consider these GIBSONs and JUSTICEs to be just
one family, then the markers highlighted in green switch from being GIBSON
signature markers to being GIBSON-JUSTICE branch markers. |
| Bottom line: everyone needs to upgrade to 67 markers!
And the person tested elsewhere (GX-1) needs to join the project at FTDNA,
then upgrade to 67 markers. |
|
