GENEALOGY-DNA-L Archives

Archiver > GENEALOGY-DNA > 2002-04 > 1019666478


From: "Allan S. Gleason" <>
Subject: Re: [DNA] Relative Genetics/Ancestry.com results
Date: Wed, 24 Apr 2002 09:41:24 -0700
References: <103.141fe35e.29f5be9c@aol.com> <5.1.0.14.0.20020423224215.04edbe70@wells.org>


Might as well throw in my two cents worth. When I had my tests done last year with
BYU/Relative Genetics, Diahan had, at that time informed me that they had upped the
mutation rate from .002 to .0025 based upon their observation that going rate was
too low. That was before all of the new markers were introduced. Since .002 was
considered the average for the original 10 or 12 markers used by the industry, it
could well be that the newer markers do have significantly higher mutation rates.

Also considering sperm in males (of course) it is known based on certain genetic
diseases that since sperm (as opposed to eggs) are constantly generating over a
man's lifetime that the sperm mutates at least five times more frequently than do
women's eggs which she has from birth - Huntington's disease is one major example.
So perhaps from my 'off the street' knowledge it stands to reason that perhaps most
mutations come from male sperm which are a function of the father's age. Seems to
make sense to me. I know, guys, it is much better to blame women's old eggs for
problems than to consider men's tadpoles to ever be at fault.

I would also suggest that Dr. Woodward has a unique advantage over most if not all
geneticists in that he is a professor at Brigham Young University (for you newbies)
and is head of the largest genetics project going which involves 100,000 donors
world wide. These donors are expected to have genealogies at least four generations
deep. The project is far from complete, but I suspect that he and his grad students
have already gotten quite a bit of data.

Bear in mind that genetics workers in the field of paleoanthropology valued markers
which virtually never mutated since they were interested in creatures many thousands
or millions of years old. Mutations were on their "bad" list. Even forensics people
aren't thrilled about haplotypes mutating. Now along comes "popular genealogy"
(where popular means lucrative) where everyone wants to be able to resolve
individual generations so the drive is toward relatively "unstable" markers. It is
true that generational resolution can be achieved by increasing the number of
markers, but that has already been done to a great extent with increased cost.
However, as the graph at FTDNA's website shows, there is a practical limit to
increasing markers to say nothing of finding them and researching their properties.

Finally, I understand that it is always best to end with a question, so, since
mutations are considered to be random events throughout the genome, other than mere
size in basis points, why are some locations more random than others - or are they?
8>0

Allan
PS: Reminds me of non-random random number generators (algorithms) used in
calculators. Or if God is infinite, is infinite space non-infinite? Just kidding!




"Orin R. Wells" wrote:

> At 09:55 PM 4/23/2002 -0700, Brett Miller wrote:
> >Just for the sake of argument, lets say mutations increase during the peak
> >of the 11 year sun-spot cycle. That would throw off a lot of studies that
> >use lots of one generation events within a short time period.<<
>
> This is an interesting observation and, of course, there are no studies
> complete enough at this point to even suggest that this might indeed be the
> case. For now everyone is assuming that the mutations happen rather
> randomly although they want to put a predictable rate on them. The rates
> are probably invalid if the real driving force is something entirely
> different. We have speculated on this list that the frequency might
> actually increase with the age of the parent. Until someone has enough
> public data where we can trace specific mutations to a particular ancestor
> and start collecting the information on age of the parent at conception,
> phases of the moon or whatever anyone can think to toss in, we are not
> going to be able to even seriously hazard any real guesses. At this point
> I have seen no one even attempt to try to associate the differences between
> descendants to the ancestor, age or anything else. We really don't have
> enough data among us yet to even begin to do this.
>
> >It makes sense to me to actually USE genealogy, as Dr. Woodward does, to
> >find the "many-generation" mutation rate that will then be
> >applied back to determine genalogical unknowns.
>
> I think it has to go deeper than I suspect Dr. Woodward may have been able
> to achieve with his studies to date. What is needed is a number of large
> studies where a broad number of descendants are used to identify
> mutations. Then additional focused descendants from specific branches of
> the family are going to be needed to identify the exact ancestor in whom
> the mutations happened. A number of these occurrences will be necessary to
> establish/recognize a pattern if one exists or not if it does not
> exist. The answer may be some natural set of circumstances or it may turn
> out to be exactly random. I believe from talking to Dr. Woodward that he
> is interested in following this sort of path but I do not know whether he
> has had any proper opportunities to do so.
>
> Orin R. Wells
> Wells Family Research Association
> P. O. Box 5427
> Kent, Washington 98064-5427
> <>
> http://www.rootsweb.com/~wellsfam/wfrahome.html
> Subscribe to the "Wells-L" list on RootsWeb
>
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