GENEALOGY-DNA-L Archives

Archiver > GENEALOGY-DNA > 2010-02 > 1266990586


From: Thomas Krahn <>
Subject: Re: [DNA] Hello Mr. Krahn
Date: Tue, 23 Feb 2010 23:49:46 -0600
References: <9a804091002231904y6e27ed67g287b8f27361b1274@mail.gmail.com>
In-Reply-To: <9a804091002231904y6e27ed67g287b8f27361b1274@mail.gmail.com>


Dear ab10man2,

First I need to mention that I definitely do not have a Dr. title so please
leave it away before I get into trouble.
My university degree is Dipl-Ing. Biotechnology from the Technical
University Berlin
and I specialized in molecular genetics. This is the subject where I can
definitely try
to answer your questions. However I don't feel familiar enough with
population statistics
and history (esp. not Arabic or Jewish history) so that I unfortunately
cannot answer some of your questions.


ab10man2 wrote:
> Hello Dr. Krahn,
>
> I hope you get this message doing well. I am sorry to contact you by this
> e-mail but it is the only one that I found for you. I have tested a
> y-chromosome test with Family Tree DNA, and it showed my haplogroup to be
> J1e.
>
> Later, I tested the snp l222.2 and it was positive in my kit. These tests
> confirmed that I have a Semitic Arabic origin in my paternal line.
>
> I have been in contact with so many experts and scientists including Mr.
> Greenspan and Ms. Schrack about the new developments within this haplogroup.
> I want to say that, honestly, getting answers to my questions from you would
> be the most perfect way to have them answered for ever..
>
> I hope you take a look at them, and provide me with the answers if you would
> like - for sure.
>
>
> Q1: I know that we now have a newer tree of the haplogroup J1 in ISOGG
> website. Would you estimate the time of when l222.2 is going to be added to
> the haplogroups' tree in ftdna.com ?
>
This is just a organizational decision that needs to be done by the FTDNA
management as soon as the IT group has the time to make the modifications
on the website. I have no influence on this. The GRC lab can't see a
difference
whether the order is from a deep clade test or from the advanced orders
page.
>
> Q2: Since we have more than 400 Arabic kits now, have been there any
> developments in the project WTY ( or WTY2 if it has been started ) in
> finding new mutations within J1e under l222.2 ? And is l222.2 a back
> mutation ?
>
L222.2 is not a back mutation. It is a parallel mutation.
L222.1 shows up in E-M2 samples.
There where several J-L222.2 participants among the WTY participants so far.
I am not aware of any systematic testing strategy/group that tries to
divide J-L222.2 further though.

> Q3: Would we have the ability to assign different snp's for each Arabic and
> Jewish tribe in the future ?
>
There are probably enough SNPs on the Y chromosome to find a distinct
SNP for
each individual male. The question is rather if members of each "tribe"
share enough
markers so that you can identify a clear border around your "tribe"
definition.
This I can't answer.
> Q4: Is Family Tree DNA having a genetic conference this year ? ( I am
> asking since we used to hear good news from such conferences).
>
I have heard discussions about it but I can't confirm a definitive "yes"
yet.
I don't have a date either.
> Q5: Do you think that we might need to test more markers in the future to
> determine TMRCA ?
>
It depends on what level of resolution and confidence your genealogical
research requires.
In general more markers will increase resolution and confidence of a
TMRCA calculation.
Especially if we are looking at the time before the surnames and
genealogical records the resolution
of the TMRCA calculation is rarely sufficient to draw reliable
conclusions. With new SNPs we
may not be able to calculate exact dates, but at least we are able to
put events into a chronological order.

However if you have genealogical records and are therefore able to
simply count the generations
then a 67 marker match is more than enough to confirm this exact TMRCA.
Then it doesn't even
matter if you have a few STR mutations or not. The TMRCA won't change
because the genealogical record
is more precise. No further testing is necessary in this case.
> Q6: Do you recommend using: ( trees or calculators ) in finding TMRCA
> between people that have more than 8 markers difference ?
>
No because I can't evaluate how reliable the calculators are. Other
experts on this list may give you a better informed answer.
> Q7: Do mutation rates change if we test more people of the same subclade ?
>
The mutation rates itself don't change depending on what you test.
However our measurement value comes closer to the real mutation rate the
more independent persons we test.
If we are selecting the testing persons from a distinct subclade then
we'll approach the mutation rate valid for that specific subclade which
may be a different mutation frequency than in another subclade.
Differences are usually small.
However biochemical reactions are complex systems that can be influenced
by a huge number of border conditions
> Q8: Would you recommend that I do the WTY test or not ?
>
I don't want to influence you in either direction. If a new SNP may be
helpful with your personal research you should give it a try.
If you don't have many matches in the STR database it may be better
worth to spend the money for testing multiple persons among your
relatives to get a clearer picture about your genealogy.
> Q9: Can I rely on 25 markers match or do I need to take 67 markers matches
> in consideration ONLY?
>
>
This depends on the question that you want to solve. The statistical
experts on this list may be able to give you quantitative formula on how
to calculate the number of necessary markers to solve your question at a
distinct confidence level.

I hope this helps,

Thomas


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