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.
aknak at aksoto dot idps dot co dot uk