Yesterday, one of the Rootsweb listservers went down, and there was chatter on
various lists about messages being delayed. The best course in such cases is
usually to just be patient and wait. Well, it's been 22 hours since posting my
reply to Linda, and it still hasn't shown up. On the chance that the message
was lost, not just delayed, I'm giving it another try. If you end up eventually
getting the original message, too, my apologies.
Diana
-----Original Message-----
From: Diana Gale Matthiesen [mailto:DianaGM@dgmweb.net]
Sent: Monday, August 20, 2007 5:25 PM
To: 'carrico-dna(a)rootsweb.com'
Subject: RE: [CARRICO-DNA] Node Chart for Peter CARRICO I
Linda,
The mutations each subject has only to himself did happen
later, in some generation after Peter I, but before
themselves. We don't know, yet, where. The values that they
all share had to have occurred before Peter I because those
were the values he transmitted. Peter might have been
carrying, at most, one new mutation from his father. We
won't know that until we've hooked up with his originating family.
These subsequent mutations, in our tested subjects, could
have happened in any generation, even the current one. I
have twice had reason to test brothers in my family. In one
case, the brothers matched 67/67, but in the other, they
matched 66/67. In the latter case, a mutation occurred
between the father and one of his sons. We know which one
because one of the brothers matches his cousins, while the
other is off by that one mutation. In other words, one of
the brothers is modal at that marker (same value as his seven
tested cousins), while the other brother is unique in the
family for that marker.
The mutation occurs during "spermatogenesis," the biological
process whereby an undifferentiated cell in the father's
testicle is transformed into a mature sperm (independent,
with a means of propulsion). Just that one sperm carries the
mutation, so it is transmitted to just one son. From then
on, the son bearing the mutation will pass it on to all of
his sons. That's how we're able to pin-point where a
mutation took place, provided we have enough test subjects.
The odds against the same mutation happening twice in sperm
transmitted by one father are so astromical that it is taken
as a given that any particular mutation is a one-time event
transmitted to only one son. The odds against one father
having more than one son with *any* mutation, much less the
same mutation, are also astronomical -- unless the father
works in a nuclear power plant... Seriously, mutations are
fundamentally rare events, which is the reason this method works.
Diana
P.S. There's something to be said for, ultimately, testing
all of your living male blood relatives. You don't know what
you'll turn up. Maybe nothing unexpected, but that's a nice
outcome, too.
> -----Original Message-----
> From: carrico-dna-bounces(a)rootsweb.com On Behalf Of Linda Boorom
> Sent: Monday, August 20, 2007 1:56 PM
> To: carrico-dna(a)rootsweb.com
> Subject: Re: [CARRICO-DNA] Node Chart for Peter CARRICO I
>
> I have, I guess, 2 questions.
>
> Is it not possible that some of these mutations took place
in more recent generations?
> If so, I understand the need to have more "cousins" tested,
as even with first cousins, there could
> be a slight difference?
>
> OK, so I have three (3) questions :-)
>
> When a mutation takes place, does it take place in all
sons? For example, I have 3 brothers. If all
> 3 brothers were tested as well as my father, if the
mutation took place in my father's offspring (&
> not in him), would all 3 brother's have the same mutation,
or could just one of the 3?
>
> Just curious.
>