GENEALOGY-DNA-L Archives
Archiver > GENEALOGY-DNA > 2000-11 > 0974049200
From: "Bettie Rehling" <>
Subject: Re: [DNA] Scott Woodward at Saint Marys County, MD event
Date: Sun, 12 Nov 2000 11:13:20 -0600
References: <44.8ab9116.273ff34f@aol.com>
Dear Anne, Dennis and Scott,
Many thanks for your kind responses to my query. Your explanations were
truly useful, and cleared up a number of my questions. I'm relieved that
what I had come to believe is right..and sad to have it confirmed that I
have to wait for more pieces of the puzzle to get past my genealogy dead
ends. Locating male descendants of the brickwall ancestors is certainly an
interesting option. I appreciate all your help!! Great Site! Bettie
Many thanks for your
----- Original Message -----
From: <>
To: <>
Sent: Sunday, November 12, 2000 7:21 AM
Subject: Re: [DNA] Scott Woodward at Saint Marys County, MD event
> In a message dated 11/11/00 7:05:26 PM Pacific Standard Time,
> writes:
>
> > but surely there is more DNA than just the two lines??
>
> Yes, indeed. The entire human genome has 23 chromosome pairs in the cell
> nucleus. It is 3 billion "bases" in length. Bases are the chemical units
that
> string together to form the code, abbreviated A for adenine, T for
thymine, G
> for guanine, and C for cytosine. The Y chromosome only has about 60
million
> bases and the mtDNA outside the nucleus only has 16K (although there are
many
> copies in each cell).
>
> The reason we place so much emphasis on Y chromosome and mtDNA testing
here
> is that you know with certainty where you got your Y chromsome and your
> mtDNA. For your other chromosomes, you know you got one of the pair from
your
> father and the other from your mother. But you don't know whether the one
> your father gave you came from HIS father or HIS mother. For an additional
> complication, chromosomes can swap parts -- this is called "crossing
over."
> This means the chromosome your father gave you could be 2/3 from your
> paternal grandfather and 1/3 from your paternal grandmother.
>
> All of this makes tracing relationships very fuzzy, which is why I posed
my
> question for Scott Woodward re the utility of collecting four generation
> pedigree charts.
>
> If you can find a high school or college biology text, you could follow
the
> diagrams better than my explanation, I'm sure. Which reminds me, back when
I
> was in high school, we didn't even know how many chromosomes there were! I
> was taught that we have 48.
>
> Ann Turner
>
>
> ==============================
> Shop Ancestry - Everything you need to Discover, Preserve & Celebrate
> your heritage!
> http://shop.myfamily.com/ancestrycatalog
>
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