I always knew they were different

[Gerry]

Yeah, we needed years of "scientific research" to tell us this...as if any
boy with a mother or girl with a brother couldn't figure it out.
G


----- Original Message -----
From: "Harry Edwards" <laughingwolf at ev1.net>
To: "ghetto survivors" <austin-ghetto-list at pairlist.net>
Sent: Thursday, March 17, 2005 10:21 AM
Subject: Fwd: I always knew they were different




Begin forwarded message:

> From: Harry Edwards <laughingwolf at EV1.NET>
> Date: March 17, 2005 10:58:02 AM CST
> To: GHETTO2 at LISTS.WHATHELPS.COM
> Subject: I always knew they were different
> Reply-To: Remembrances of Austin Ghetto <GHETTO2 at LISTS.WHATHELPS.COM>
>
>
> http://www.latimes.com/news/science/la-sci-
> xchromosome17mar17,1,6092863.story?coll=la-news-science
>
>
> THE NATION
>
> Women Are Very Much Not Alike, Gene Study Finds
>
> X chromosome diversity among females suggests that in effect 'there is
> not one human genome, but two -- male and female,' researcher says.
>  By Robert Lee Hotz
>  Times Staff Writer
>
>  March 17, 2005
>
>  Scientists have found genetic evidence for what some men have long
> suspected: It is dangerous to make assumptions about women.
>
>  The key is the X chromosome, the feminine sex chromosome that all men
> and women have in common.
>
>  In a study published today in the journal Nature, scientists said
> they had found an unexpectedly large genetic variation on the X
> chromosome among women. The findings were published in conjunction
> with the first comprehensive decoding of the chromosome, which
> appeared in the same journal.
>
>  Females can differ from each other almost as much as they do from
> males in the behavior of many genes at the heart of sexual identity,
> researchers said.
>
>  "Literally every one of the females we looked at had a different
> genetic story," said Duke University genetics expert Huntington
> Willard, who co-wrote the study. "It is not just a little bit of
> variation."
>
>  The analysis also found that the obsessively debated differences
> between men and women were, at least on the genetic level, even
> greater than previously thought.
>
>  As many as 300 of the genes on the X chromosome may be activated
> differently among women than among men, said molecular biologist Laura
> Carrel at Pennsylvania State University College of Medicine, the other
> author of the paper.
>
>  The newly discovered genetic variation among women might help account
> for differing gender reactions to prescription drugs and the
> heightened vulnerability of women to some diseases, experts said.
>
>  "The important question becomes how men and women actually vary and
> how much variability there is in females," Carrel said. "We now might
> have new candidate genes that could explain differences between men
> and women."
>
>  All told, men and women may differ by as much as 2% of their entire
> genetic inheritance, greater than the hereditary gap between humankind
> and its closest relative — the chimpanzee.
>
>  "In essence," Willard said, "there is not one human genome, but two —
> male and female."
>
>  Scientists estimate that there may be as many as 30,000 genes in the
> chemical DNA blueprint for human growth and development known as the
> human genome.
>
>  The genes are parceled out in 23 pairs of rod-like structures called
> chromosomes contained in every cell of the body.
>
>  The most distinctive of the chromosomes are the mismatched pair of X
> and Y chromosomes that guide sexual development.
>
>  Until now, researchers considered the shuffle of sex chromosomes at
> conception a simple matter of genetic roulette.
>
>  The chromosomes that dictate sexual development are mixed and matched
> in predictable combinations: A female inherits one X chromosome from
> each parent; a male inherits an X chromosome from his mother and a Y
> chromosome from his father.
>
>  To avoid any toxic effect from double sets of X genes, female cells
> randomly choose one copy of the X chromosome and silence it — or so
> scientists had believed.
>
>  The new analysis found that the second X chromosome was not a silent
> partner. As many as 25% of its genes are active, serving as blueprints
> to make necessary proteins.
>
>  To investigate this variation, Carrel and Willard isolated cells from
> 40 women and measured the activity of hundreds of genes to see whether
> those on the second X chromosome were active or silent.
>
>  Although those extra genes were supposed to be turned off, they found
> that about 15% of them in all female cells were still active, or in
> the terminology of genetics, "expressed." In some women, up to an
> additional 10% of those X-linked genes showed varying patterns of
> activity.
>
>  "This is 200 to 300 genes that are expressed up to twice as much as
> in a male or some other females," Willard said. "This is a huge
> number."
>
>  Researchers were surprised that they found so many unexpected
> differences in the behavior of the one sex chromosome that men and
> women share.
>
>  Though there is dramatic variation in the activation of genes on the
> X chromosomes that women inherit, there is none among those in men,
> the researchers reported.
>
>  Researchers have yet to understand the effect of so many different
> patterns of gene activation among women or determine what controls
> them, but all the evidence suggests that they are not random.
>
>  "What had looked like a simple yes or no has turned into a thousand
> shades of gray," said molecular biologist David Page, an expert on sex
> evolution at the Whitehead Institute for Biomedical Research in
> Cambridge, Mass.
>
>  Illuminating this complex palette was the work of an international
> team of 250 scientists led by geneticist Mark Ross at the Wellcome
> Trust Sanger Institute in Hinxton, England. The team produced the
> first complete sequence of the X chromosome about two years after the
> decoding of the male Y chromosome.
>
>  The researchers found that the X chromosome, though relatively poor
> in genes, is rich in influence, deceptively subtle, and occasionally
> deadly to males.
>
>  The international team identified 1,098 functional genes along the X
> chromosome, more than 14 times as many as scientists had located on
> the tiny Y chromosome.
>
>  Even so, the researchers said, there were fewer genes to be found on
> the X chromosome than on any of the other 22 chromosomes sequenced so
> far.
>
>  Most of the X genes are slightly smaller than average. But one is the
> largest known gene in the human genome, a segment of DNA linked to
> diseases such as muscular dystrophy that is more than 2.2 million
> characters long.
>
>  The X chromosome contains a larger share of genes linked to disease
> than any other chromosome.
>
>  It is implicated in 300 hereditary disorders, including color
> blindness, hemophilia and Duchenne muscular dystrophy. Nearly 10% of
> the genes may belong to a group known to be more active in testicular
> cancers, melanomas and other cancers, the team reported.
>
>  "The biggest surprise for us was just how many of these
> [cancer-related] genes there are on the X," Ross said. "There are very
> few of these elsewhere on the genome."
>
>  The complete gene sequence provided some clues to the origins of the
> human sex chromosomes.
>
>  The researchers found that most of the genes on the X chromosome
> reside on chromosome 1 and chromosome 4 of chickens.
>
>  That supports the theory that the human sex chromosomes evolved from
> a regular pair of chromosomes about 300 million years ago when
> chickens and humans shared a common ancestor.
>
>
>  If you want other stories on this topic, search the Archives at
> latimes.com/archives.



----------------------------------------------------------------------------
----






----------------------------------------------------------------------------
----


> >
> > Article licensing and reprint options
> >
> >
> >
> > Copyright 2005 Los Angeles Times
> >
> >
>