Newsgroups: sci.space.shuttle
From: henry@spsystems.net (Henry Spencer)
Subject: Re: Shuttle Atmosphere / Hypoxia
Date: Mon, 1 Jan 2001 02:47:06 GMT

In article <20001231103332.14112.00000094@ng-mi1.aol.com>,
Doug Goncz  <dgoncz@aol.comm> wrote:
>I've read in newsgroups that women can more easily distinguish between the
>deeper shades of red since they have an extra color sensitive cell in their
>eyes, an extra cone type to make a total of four types. The evidence given was
>that fewer women are red-color blind.
>Just a rumor?

Last I heard, it was pure speculation.  The gene for one of the light-
sensitive pigments is on the X chromosome, so it is conceivable for a
woman to have two slightly-different copies of it.  Normally, one X is
suppressed and the other one is active... but *which* gets picked is more
or less random on a cell-by-cell basis.  So a woman *could* have two
slightly different cell types with different sensitivities.  As far as I
know, there's no specific evidence that this is actually true.  (The
female ability to distinguish between, say, Mauve Mist and Faint Passion,
when males consider them identical shades of pink, is almost certainly
mostly cultural -- the result of simply paying more attention to colors.)

Women suffer much less from color blindness for the same reason as they
suffer much less from a number of other sex-linked genetic diseases:  some
of the genes involved are on the X chromosome, and women have a spare X,
so unless they have the defective gene on *both* Xs, half their cells will
be using a normal gene, and that's usually enough to provide roughly
normal functioning.  Men only have a single X -- the Y chromosome carries
almost nothing useful except sex-determination genes -- and so a single
defect takes down all of their cells.

>Let's see H+, O-. So hypoxia would be associated with alkalosis, not acidosis?

It's more complicated than that because most of the oxygen is not present
as ions.  A quick look at references doesn't turn up mention of a specific
change in blood pH.
--
When failure is not an option, success  |  Henry Spencer   henry@spsystems.net
can get expensive.   -- Peter Stibrany  |      (aka henry@zoo.toronto.edu)

Newsgroups: sci.space.shuttle
From: henry@spsystems.net (Henry Spencer)
Subject: Re: Shuttle Atmosphere / Hypoxia
Date: Mon, 1 Jan 2001 20:06:42 GMT

In article <3A50856D.25FA2A84@together.net>,
John Beaderstadt  <beady@together.net> wrote:
>> Men only have a single X -- the Y chromosome carries
>> almost nothing useful except sex-determination genes -- and so a single
>> defect takes down all of their cells.
>
>So, that would be why baldness is a predominately male trait, but is
>inherited from the mother?

That's may be part of it, although hair patterning is complex, as I
recall, and hormones figure into it too.

Hemophilia is a more prominent (and simpler) example.  It ran in several
European royal families for generations:  most boys with the gene died
before adulthood, but girls with only one bad gene survived to pass it on
to half of their children.
--
When failure is not an option, success  |  Henry Spencer   henry@spsystems.net
can get expensive.   -- Peter Stibrany  |      (aka henry@zoo.toronto.edu)