Seeking clarification in understanding genetic concepts

[Anony!]

>"Dean P McCullough"  wrote:
> Lets see if this gets back to you.
> To answer a few of your questions:
>
> Given that the genome between mouse and human is at lest 99% the same,
> the differences between one human and another is at least 99.9% the
> same.  Thus, it is very important to get a baseline, from which we can
> study the very minor variations from one person to another.

Where did you get this statistics from? Especially between one human to
another.

> It is well known that these minor changes can have a major impact on the
> individual.  For example, there is a phenomenon called tandem repeats
> where a small number (2,3,4) basis are repeated many times.  A number of
> genetic diseases have been traced to a different number of repeats in
> these tandem repeats.
>
> As for meiosis, there is recent evidence that a woman continues to
> generate new eggs.  Meiosis occurs only in the sexual organs, and is not
> something (in humans) that occurs else where.  Also, keep in mind that
> the copied chromosome is not purely from the mother or father.  There is
> many crossovers from one side of the chromosome to the other.  Though
> there is a greater likelihood that adjacent genes on the same
> chromosomes are from the same parent, in general, across the chromosome,
> this is not true.  I do not believe we have a good handle yet on the
> expected number of cross overs that occur.
>
> Hope this helps.
>
> > Hello all,
> >
> > I'm trying to understand about genetic engineering by reading the
> > relevant articles on www.wikipedia.org, but I'm having some difficulty.
> >
> > First of all, there's the article on genomes, where it says:
> >
> > "In biology, the genome of an organism is a complete DNA sequence of
> > one set of chromosomes..."
> >
> > For me, this means that each genome will be different for each
> > person. But I know that recently, there has been a project going on
> > to describe the "human genome". I assume that this cannot then refer to
> > a single person, but then how possible is it to arrive at a 'generic
> > genome' for all of humanity?
> >
> >
> > Also, I've been trying to understand meiosis. Am I correct in saying
> > that this only happens when sperm or egg cells are being made?
> > At what time in a human beings life would this be - is this a
> > continuous process, or a one off? I ask, because I seem to recall
> > reading that a woman has all the eggs that she will ever produce
> > when she is born.
> >
> > Also, am I right in saying that each of these reproductive cells
> > has a different combination of genetic material from the person
> > that produces it, depending on which of the 23 chromosomes is
> > selected from either his mother's chromosome set or his father's
> > chromosome set and on the effects of 'crossing over' during meiosis?
> > How much 'crossing over' actually takes place - does it occur at
> > multiple points in each chromosome?
> >
> > Thanks in advance for any answers or confirmations.
> >
> > --
> > Akin
> >
> > aknak at aksoto dot idps dot co dot uk
>
>
>
> --
> Dean P McCullough
> 410 997 7506
>
>


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