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Archiver > Y-DNA-HAPLOGROUP-G > 2008-07 > 1216579797


From: "Ray Banks" <>
Subject: [Y-DNA-HAPLOGROUP-G] PRIVATE REPLY - DNA terms
Date: Sun, 20 Jul 2008 11:49:57 -0700
References: <bee.2b6b5045.35b49a69@aol.com>


Jim,

I reply privately when the questions posed are likely to be of interest to
the person posing them, but probably are not of general interest.

There is more explanation at my web site on DNA -- not the links at bottom
http://www.members.cox.net/morebanks/G2Ideas.html
[The "I" in Ideas must be capitalized if copied]

For even more detail, you will have to purchase a textbook dealing with
genetics and population genetics.

For the other information you requested, visit the first part of the
sections on Early Origins of Haplo G

http://www.members.cox.net/morebanks/G2Ideas.html

What you seem to requesting is a migration report for your specific family.
It has been incredibly difficult typing migrations to large groups of
persons in the last 2000 yrs and almost impossible for individuals. An
individual can move thousands of miles in a single lifetime. This request
for a family-specific migration history is the most common question I
receieve, and I never have an answer.

You will not great variation in population genetics books for the
geograpghic origins of haplo G as well as large time differences. For
persons in the Genographic Project, a simple explanation such as they
provide is helpful, but it also implies there is concensus as to timing and
location, which is not the case. Haplo G arose during a period of
hunter-gatheirng and families could move large distances following herds.
The time calculations are based on limited samples. Mutation processes at
STR markers are subject to complicated reversals hiding mutations. And time
calculations are based on the number of mutations found. The scientists use
fudge factors to try to overcome this, but some skepticism exists about
this. The only way to overcome this is to test ancient carbon-dated
skeletons for presence of haplo G, and so far not one such specimen has been
located.

You may find these paragraphs from my Banks project also helpful

The markers on the Y chromosome
The 37 markers of the Y chromosome being used for the Banks DNA project are
reported as numbers. These represent the length of segment of a DNA site.
The varying lengths are caused primarily by insertions or deletions at
certain points during the slightly imperfect process that creates a new
strand. An insertion increases the number and length; a deletion does the
opposite. There is some variation in how parts of the large DNA chromosome
are prone to deletion or insertion. The final scientific article on this
subject listed below specifically observed the changes at the portion of DNA
used in our genealogy testing and found insertions to outnumber deletions by
a ratio of 5 to 2. Although the number of mutations was not large in this
study, this is all that is available and would seem to argue that marker
values in deep ancestry will tend to be lower. For example, where value
ranges at a marker are reported to range from 11 to 15 among all test
subjects, the 14 and 15 would seem to be more recent changes within the
haplogroup. There may or may not be flaws in this logic.
Articles:
1994 Deletion bias found in rates of insertion and deletion in non-coding
parts of DNA in primates.
1995 Deletion bias in rates of evolutionary insertion and deletion in
pseudogenes
2002: Bias toward insertion in nucleated cells.
2003 Deletions more common in pseudogenes
2003: Deletions more common than insertions in coding parts of DNA.
2000: Expansion of size more common in short DNA repeats; contraction in
longer ones.
2000: Bias toward lengthening found in short-tandem repeats on Y chromosome
2005: Bias toward lengthening found in short-tandem repeats on Y chromosome

Mutation rates.
Scientists have prepared charts and calculation programs that allow one to
calculate how many generations lie between one test subject and another test
subject and their most recent common ancestor. This is not a precise
number, but rather a range of numbers. Probably the most useful portion of
these graphs is the maximum number of generations. Typically, a single DNA
marker will experience a mutation once in every 500 generations. My math
may not be precise, but typically a 12-marker group should have one mutation
every 24 generations, and a 37-marker group should have a mutation every 3
generations. The range of possibilities includes no mutations in 500
generations at one extreme and multiple mutations in a single generation at
the opposite extreme—these extremes are both very rare events. Occasionally
a mutation will change the value by two numbers rather than one. A firm
definition of generation does not exist but is somewhere between 25 and 30
years. I usually use 30 yrs to be conservative.
Articles
Mutation rates in sperm DNA from single individuals
Mutation rates in Y chromosome in large number of father and son pairs
Mutation rate found in 692 N. American father-son pairs, Y chromosome loci
Mutation rate found in 3,026 Spanish/Potuguese father-son pairs, Y
chromosome loci

In testing for 37 markers, a perfect match of the markers indicates the two
subjects likely had a common male ancestor no more than 21 generations ago
at most. If only 36 markers match, this indicates a common ancestor would
likely have existed no more than 35 generations ago. If only 35 markers
match, this indicates a common ancestor would likely have existed no more
than 58 generations ago. On average the common ancestor is often more
recent than these maximum number of generations.

The maximum distance to the most common ancestor is very useful information
in identfying whether the various Banks families in the U.S. are related to
each other.

Mutation rates were calculated by (a) comparing the DNA changes in a large
number of fathers and sons and (b) determining the mutation rate within a
large sample of sperm cells of several men. (see links above) These can be
expensive tests to conduct, and the testing has never been done using just
the specific markers used in the genealogy testing. It is known that some
families have faster mutations than others so there is some imprecision in
the whole process. As best as can be determined, the standard mutation
rates used in the charts are the slowest. So information from the faster
mutating families do not interfere with the conservative calculation of the
farthest possible number of generations to the most recent common
ancestor—which is of most interest.

You only have 12 markers. We have not been able to reliably establish
relationships for ancient times except with 67 markers. See my clade pages
in the second section on the page covering this.

Ray Banks

----- Original Message -----
From: <>
To: <>
Cc: <>
Sent: Sunday, July 20, 2008 6:40 AM
Subject: [Y-DNA-HAPLOGROUP-G] Need Help: Haplogroup G2


>
> Dear Friends,
> I am new to this list. Be aware that I am neither a geneticist nor a
> scientist, but I am a businessman who has a hard time understanding most
> of the
> posts on this list. I had my DNA tested for National Geographic’s
> “Genograhic
> Project.” Let me give you the results, then I have a question.
> My Genographic Project results say I belong to Haplogroup G2, carrying
> the
> following Y-chromosome markers: M168 > M89 > M201 > P15
> Furthermore it says my Short Tandem Repeats (STRs)/Loci are as follows:
> 14/393; 14/19; 10/391; 11/439; 12/389-1; 17/389-2; 13/388; 22/390;
> 11/426;
> 15/385a; 15/385b; and 11/392. Believe me when I say I can partially
> understand the
> Mutations (M), but have absolutely no understanding of STRs and Loci or
> what
> they mean. One of the problems one gets from National Geographic’s “
> Genograhic Project” is that its very generic, doesn’t explain most of the
> terminology used and the haplogroup G2 just “stops” in Greece.
> Project: My grandson will belong to the same Haplogroup with the same
> markers. I am trying to write a paper which explains his “Genetic
> History” and the
> geographic migration of his G2 haplogroup over the last 60,000 years for
> my
> 15-year old grandson. In order for it to be somewhat interesting to him I
> am
> trying, with minimal success, to put as much in laymen’s language as is
> possible.
> QUESTION: Based on my G2 haplogroup, Y-chromosome makers, STRs and Loci
> does
> anyone of website(s) where I might go to get an explanation of its
> “Genetic
> History” and geographic migration through time, from inception to today.
> I
> am not looking for a 100-page professional scientific article on the
> subject,
> rather a 15 page explanation and description of our haplogroups Genetic
> History and geographic migration. Any suggestions would be deeply
> appreciated!
> Respectfully,
> Jim Forcum
>
>
>
> **************Get fantasy football with free live scoring. Sign up for
> FanHouse Fantasy Football today.
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>
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