Y chromosome
Richard Alexander
[snip]
> June 19, 2003
> Men's Survival Secret: Bending Y Chromosome
> By NICHOLAS WADE
[snip]
> As part of the work, the scientists have tallied the exact number of genes
> on the Y chromosome,
I strongly doubt that any human yet knows the exact number of genese
on the Y chromosome. I don't know why Mr. Wade made that statement.
[snip]
> Although most men are unaware of the peril, the Y chromosome has been
> shedding genes furiously over the course of evolutionary time, and it is now
> a fraction the size of its partner, the X chromosome.
[snip]
> The cost of this abstinence, however, is that most of the Y's genes have
> been rendered useless by mutation and physically shed. The X and the Y
> chromosomes were once as similar as the 22 other pairs of human chromosomes,
> and each carried about 1,000 genes. Now the Y carries fewer than 100.
How in the world can anyone be so dogmatic about genetics,
particularly about events supposed to have happened long before the
the creation of any surviving sample?
Who says the X and Y chromosomes were once the same size? How do they
know? What were the functions of the supposed lost genes? Is this
another story the geneticists are telling us, like the idea that the Y
chromosome is not good for much? Can you not see the irony, the
incredible arrogance, in someone making statements about what the Y
chromosome once was at the same time admitting how wrong scientists
have been about what the Y chromosome is? How could we be so certain
that we know what the Y chromosome was a million years ago when we
were so wrong about it a year ago?
[snip]
> The finding of 78 active genes on the Y contradicts an earlier impression of
> the chromosome as being a genetic wasteland apart from its male-determining
> gene. But if the Y is not a wasteland, important consequences ensue for the
> differences between men and women.
>
> As often noted, the genomes of humans and chimpanzees are 98.5 percent
> identical, when each of their three billion DNA units are compared. But what
> of men and women, who have different chromosomes?
>
> Until now, biologists have said that makes no difference, because there are
> almost no genes on the Y, and in women one of the two X chromosomes is
> inactivated, so that both men and women have one working X chromosome.
>
> But researchers have recently found that several hundred genes on the X
> escape inactivation. Taking those genes into account along with the new
> tally of Y genes gives this result: Men and women differ by 1 to 2 percent
> of their genomes, Dr. Page said, which is the same as the difference between
> a man and a male chimpanzee or between a woman and a female chimpanzee.
In light of what we now admit we had wrong, it sounds funny hearing
people compare the simularities of one genetic structure to another,
sort of like listening to someone convert units with far too many
digits of precision.
[snip]
Tim Tyler
: "The Professor" <sgho...@aol.comrade> wrote in message news:<hbtIa.2342$1n....@twister.nyroc.rr.com>...
:> The cost of this abstinence, however, is that most of the Y's genes have
:> been rendered useless by mutation and physically shed. The X and the Y
:> chromosomes were once as similar as the 22 other pairs of human chromosomes,
:> and each carried about 1,000 genes. Now the Y carries fewer than 100.
: How in the world can anyone be so dogmatic about genetics,
: particularly about events supposed to have happened long before the
: the creation of any surviving sample?
: Who says the X and Y chromosomes were once the same size? How do they
: know? [...]
Everyone - AFAIK - and by looking at distantly-related asexual organisms,
who never developed Y chromosomes - and never had their genes suppressed
by other nuclear genes - and never bled most of them.
: What were the functions of the supposed lost genes? [...]
They would have matched those on the X chromosome. Indeed they
would have /been/ X chromosomes.
--
__________
|im |yler http://timtyler.org/ t...@tt1.org
Richard Alexander
> Richard Alexander <po...@aol.com> wrote:
> : "The Professor" <sgho...@aol.comrade> wrote in message news:<hbtIa.2342$1n....@twister.nyroc.rr.com>...
>
> :> The cost of this abstinence, however, is that most of the Y's genes have
> :> been rendered useless by mutation and physically shed. The X and the Y
> :> chromosomes were once as similar as the 22 other pairs of human chromosomes,
> :> and each carried about 1,000 genes. Now the Y carries fewer than 100.
>
> : How in the world can anyone be so dogmatic about genetics,
> : particularly about events supposed to have happened long before the
> : the creation of any surviving sample?
>
> : Who says the X and Y chromosomes were once the same size? How do they
> : know? [...]
>
> Everyone - AFAIK -
I suppose that is informative, within the vague parameters of the
word, "everyone."
> and by looking at distantly-related asexual organisms,
> who never developed Y chromosomes - and never had their genes suppressed
> by other nuclear genes - and never bled most of them.
I can see how one might make an imaginative story connecting such
ancient organisms with us, but that is far from actually being witness
to the progression. I am concerned that such theories--based as they
are on the absence of alternative data--are prone to gross errors.
How would you test the claim that the human Y Chromosome descended
from the chromosomes of asexual organisms? How would you falsify the
theory?
> : What were the functions of the supposed lost genes? [...]
>
> They would have matched those on the X chromosome. Indeed they
> would have /been/ X chromosomes.
Again, how could you test such a claim? How would we know if you were
wrong?