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Family Finder - The Big Picture? #dna


Martin Davis (com)
 

I received below a helpful clarification >from Max Blankfeld at FTDNA which I
am sure others would wish to see.

Martin

Martin Davis - London (UK)

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From: Max - Family Tree DNA [mailto:max@familytreedna.com]

Martin, this is what I sent to Steven Bloom, who had similar questions. You
are welcome to post it to the list:

Here are the main problems that Jews have in trying to identify common
ancestors - as you certainly know?
a) lack of a common surname prior to late 1700?s early 1800?s
b) inbreeding population
c) many unrelated lines adopting same surnames
d) many related lines adopting different surnames
e) many surnames being adapted to the land where descendants moved in

To put it in simple terms it makes the work for us, Jews, a little more
complicated as we cannot trace people as easily as the others would be able
to. Our trees in general are much shorter. It's harder for us to focus on a
certain path/line. To do that we need more people to be tested, and combine
more with Y, mtDNA and X to help identify lines given the combined results
from all tests.
So, in terms of a Family Finder result, a 3rd cousin match, given the
inbreeding, may show a total value of centimorgans composed >from the
combination of different lines due to that inbreeding, and thus, what the
algorithm guesses to be a 3rd cousin, may in fact be a more distant cousin.
Example: I had a case of a person that matched with my nephew (my brother?s
son) as a 2nd cousin, and with me as a 4th cousin. If we were talking about
matching with just one line, he should be 3rd, and I 4th. But because he may
be adding blocks of DNA >from his maternal line (unrelated to me) to the
relationship with that person, those blocks, adding up to the my main block
with him, elevates by one generation his matching to that person.
I hope this was not too confusing.
Therefore, the names that don't make sense to you are there as a match
because of inbreeding, which makes them look more closely related than they
really are, and therefore unknown to us.
Another example >from my own matches related to change of names: I have one
match predicted as 4th cousin with the last name Rubio - typical Hispanic
name (I also had the first and middle Hispanic names). My first reaction was,
what is this name doing there?? Well, I checked his record and there's a
note there: his ancestral name was Rubizewsky? well, I checked JewishGen and
I saw 2 records >from a very small town in Belarus with the name Pinsk. And
guess where my mother is from? Yes, you guessed it right: Pinsk!
So, this is a most probable case of inbreeding, combined with a change,
generations later, to a Hispanic name.
In short, while you should not dismiss those "make no sense matches", you
should certainly weight in all the factors I mentioned above.
As we gather more Jewish samples we will be able to adjust the algorithm to
reflect all those factors.
In the meantime, I can tell you that we've already had several success
stories coming out of the Family Finder test.

E-mail me anytime!

Max Blankfeld
Vice-President, Operations and Marketing
http://www.FamilyTreeDNA.com


Arline and Sidney Sachs
 

Max Blankfeld, VP of Family Tree DNA wrote:

Here are the main problems that Jews have in trying to identify common
ancestors - as you certainly know?
a) lack of a common surname prior to late 1700's early 1800's
He is talking about Ashkenazim and not most of the other Jews. Most of
them did had family names for over 500 years.

b) inbreeding population
He is is right about inbreeing. Let look at the numbers of Ashkenazim.
In 1500, it is estimated that the numbers were between 15,000 to 20,000.
By 1800 the number were about two million and 100 years later, eight
and half million. This means that on the average for each couple, there
were 3 children living long enough to had the following generation.
Using this figure of three children per couple, each couple would have
729 ggggreatgrandchildren with no inbreeding. Going the other way, each
of us have 16 pair of gggreatparents. If cousins did not married, we
would have over 23,000 5th cousins. Then if one takes any two
Ashkenazim, the chances not being related are 1 over the square of
23,000 which equal to 1 over half billion.

c) many unrelated lines adopting same surnames
For example, just look at the different haplogroups than the name
"Cohen" are in.

d) many related lines adopting different surnames
I run a haplogroup project called J2b_455-8. Everyone in it are J2b
with the value on DYS 455 of 8. The founder person (MCRA) is estimated
to lived less than 1000 year ago. Out of the 59 persons that I found
belonging to our haplogroup J2b2e, there were 53 different surnames.

e) many surnames being adapted to the land where descendants moved in.,
Some of the names in my project are Arnold, Brown, Cole, Gorden,
Perkins, Scott and Smith.

What Ashkenazim Jews need to do is to formed more haplogroup projects
based on the results >from Y-DNA testing or on some string values >from the
Family Finder results. Family Tree DNA is very helpful with setting them
up. Just be very careful in naming them. My group was called first as
"J2e1_H102". The "H102" is a SNP that was not part of my Y-DNA results.

Sidney Sachs
Lorton, VA


Robert Neu
 

Hi,
Relationships based on DNA testing are exactly thst. Probab;y the
best way to call the people that one shares a "related" dna with,
until proven otherwise, is "dna cousins".

However don't dismish it that easily. On a wide spectrum it does
inform you whether you have a likely dna that one, to some, to many
othet likely Jewish population, whether Oriental, Sephardic, or
Ashkenasy. Also remember that up to 9th century conversions were
allowed and frequent, hence, becoming disallowed.

As to family names most were acquired in the late 18th century,
though some had one much earlier. Nevertheless patronimics were the
rule. As an example when in the old testament the writer is presented
as Jozhua son of Nun, all it is his name: "Joshua ben Nun".

The suggestion that one would have a different dna result >from our
immediate parents is ridiculous. Remember that there were perhaps
10,000 Jews in Europe of the 10/12th Century. Looking at it another
way it means that by then we are all related.

Among the ways Jews came to Europe is the conquest of Rome in the
first century , and the second century CE when Masada and Bar Kochba
were defeated. Remember that The Roman soldiers were ***not Romans***
but more than likely Germanic and that the retiremeent plan, after
twenty five years of survival, was the prisoners you took and a piece
of land near the borders of the Roman Empire.

So, yes some of us may have DNA that is not 100% >from the Middle East.

So let us be tolerant even in our DNA cousins.

Robert Neu