From: cms@philabs.philips.com (Caroline M. Shone)
Newsgroups: alt.birthright,alt.abortion.inequity,talk.abortion
Subject: Re: Shameless attack on pro-choicers in general!
Date: 21 Aug 92 21:10:53 GMT
Organization: Philips Laboratories, Briarcliff, New York

In article <1992Aug14.022124.3457@ucsu.Colorado.EDU> knapp@spot.Colorado.EDU (David Knapp) writes:
>In article <1992Aug10.161448.6148@csus.edu> chaneysa@nextnet.csus.edu (Stephen A Chaney) writes:
>>
>>This is supposed to be a devastating attack? Okay, Mr. Perez, get out
>>your pen and paper, class is in session: 
>>
>>1) Not one single cell in the human body has genetic codes for other
>>organs except for that organ which the given cell is a part of.
>>Stomach cells only have stomach cells, with no provision for brain
>>cells or arm cells.
>>The zygote cell does, in fact, have within it, departments WRT
>>his/her genes, that handle arm, leg, and stomach growth.  
>>FACT: Not one cell in your body differentiates. Only the zygote can do
>>that. This fact contradicts your first point. 
>>2) Twins: The presence of twins produces the question of whether we
>>have one human individual, or two, within the same zygote. DEFINITELY
>>NOT ZERO. Triplets means we have three individuals growing out of one
>>zygote. Quadruplets? FOUR individuals. All of whom are sitting in that
>>one zygote, and growing out. They couldn't grow out unless they were
>>there in the first place, at fertilization. 
>>This contradicts your second point.  
>>
>
>I thought you all might be interested to hear what a biology expert has
>to say about Mr. Chaney's biological comments above.
>
>
>Professor Purves' response to Mr Chaney's claims follows.
>
>> 1) Not one single cell in the human body has genetic codes for other
>> organs except for that organ which the given cell is a part of.
>> Stomach cells only have stomach cells, with no provision for brain
>> cells or arm cells.
>> The zygote cell does, in fact, have within it, departments WRT
>> his/her genes, that handle arm, leg, and stomach growth.  
>> FACT: Not one cell in your body differentiates. Only the zygote can do
>> that. This fact contradicts your first point. 
>
>Just about every statement in this paragraph is false.  Especially
>the "FACT."
>
>> 2) Twins: The presence of twins produces the question of whether we
>> have one human individual, or two, within the same zygote. DEFINITELY
>> NOT ZERO. Triplets means we have three individuals growing out of one
>> zygote. Quadruplets? FOUR individuals. All of whom are sitting in that
>> one zygote, and growing out. They couldn't grow out unless they were
>> there in the first place, at fertilization. 
>> This contradicts your second point.  
>
>This set of statements is hard to discuss, in that I cannot grasp
>the concept of "individuals" "sitting in" a zygote and "growing out."
>A person doesn't "grow out" of a zygote; the zygote DEVELOPS INTO a
>person.  Biologically speaking, that is...
>
>In the case of identical twins, the zygote (fertilized egg) divides;
>the resulting two cells become separated; and each of those cells
>DEVELOPS INTO a distinct person.  In a single birth, the products
>of the first division of the zygote stay together and develop
>(roughly speaking) into two halves of the resulting person.
>
>> 1) "Sperm and ova do this with the right conditions..."
>> Interesting that the condition required, is fertilization. Which
>> points right back to where life begins... 
>
>I don't find that either participant in this debate is getting
>anywhere.  For what it's worth, it is possible in some cases to
>raise plants from pollen that hasn't participated in fertilization.
>Male ants, bees, and wasps are haploid and thus haven't resulted
>from fertilization.  Females (the vast bulk of these hymenopteran
>populations) are diploid and result from fertilization.
>
>> 2) A zygote only needs nutrients and a non-hostile environment to 
>> grow into a newborn baby. A newborn baby needs nutrients and a
>> non-hostile environment to grow into an adult. 
>> What is the difference? A zygote is proportionally inferior and far
>> more vulnerable than a newborn, but a newborn is proportionally
>> inferior and far more vulnerable than an adult. 
>
>A (human) zygote needs lots more than nutrients and a "non-hostile
>environment."  While plants can be raised from single cells in vitro,
>this cannot be done with a mammalian zygote.  Thus far, we can't
>get from zygote to baby without the maternal environment.
>
>> 1) Ova and sperm are potential humans because they do not have the
>> power to differentiate, until they fertilize. They aren't even growing
>> or developing. The z/e/f does. A common person's view of what I'm
>> saying, might be, "Feed all the chicken soup you want, to sperm, ova,
>> skin cells, or warts, but they just won't differentiate." Can't say
>> that about the z/e/f.
>
>Eggs and sperm do develop, in a biologist's terms.  Otherwise, you
>are okay with this statement.
>
>> 2) The question of identical twins can also be approached by asking,
>> "Do we have one individual human, or two?" 
>
>Identical twins are obviously two individual humans.
>
>I haven't commented on the other numbered items, because they are
>political statements rather than biological ones.
>
>
>Me (David Knapp) again... 
>
>Below I ask Prof. Purves several pointed questions relating to Mr. Chaney's
>assertions. My questions are denoted by >  His responses aren't denoted.
>
>
>> Some direct questions are:
>> 
>> Do multiple births come from multiple eggs or from whacky things happening
>> at early cell division stages.
>
>Identical twins derive from a single egg.  If the daughter cells
>produced by mitosis of a zygote separate, you get identical twins.
>Fraternal twins derive from two eggs, fertilized by separate sperm.
>
>> Is the same DNA in all cells?
>
>To a first approximation, YES.  There are exceptions.  For example,
>eggs and sperm are haploid and have only half the genetic information
>found in somatic (body) cells.  Mammalian red blood cells lack
>nuclei at maturity and hence have NO nuclear DNA.  Those white blood
>cells that give rise to the immune system splice out part of their
>DNA as part of their differentiation to become specific for a
>given antibody or T-cell receptor.
>
>However, "stomach" and "brain" cells have the same DNA except for
>chance mutations in individual cells that are not related to their
>position in the body.
>
>> Does the DNA contain the 'code' for all body parts and functions? Is 
>> the DNA in my brain cells different than the DNA in my stomach cells?
>
>Yes (first question).  No (second question).
>
>> When does a fetus get along enough to have brain activity begin? When 
>> does myelination occur?
>
>"Brain activity" is not a single, simple thing.  Some parts of the
>brain, such as the cerebellum and thalamus (for example) don't
>specialize until the middle of the second month.  At about this
>time, some reflexes are operative, and the brain may be regulating
>some of the organs.  For this to happen, myelination has to have
>taken place.
>
>The events just described aren't really fetal events, but early
>embryonic.  The term 'fetus' usually applies to an embryo at least
>two months along in its development.
>
>> You can see where this is heading, but I need the facts, no hearsay.
>
>My remarks derive from standard books of introductory biology and
>developmental biology.  I am not well informed on the last two
>questions (concerning neural development), but I looked the material
>up in outstanding textbooks.
>
>> Thanks for responding!
>
>You're welcome.
>
>(bill)
>
>Professor Purves' credentials below.
>
>B.S. Caltech 1956, Ph.D. Yale 1959.  Chaired biology departments at
>UCSantaBarbara, UConn, and (now) Harvey Mudd.  Current textbook is
>Purves, W.K. (Harvey Mudd College), Orians, G.H. (U. Washington),
>and Heller, H.C. (Stanford).  LIFE: THE SCIENCE OF BIOLOGY, 3rd
>edition.  Sinauer Associates and W. H. Freeman, Inc.  1992.  In
>use at over 110* colleges and universities this fall term.  *(Includes
>Harvard, Yale, MIT, Stanford, Michigan, Berkeley, UCLA...)
>
>From his assertation of Chaney's claims, and other experts I have talked 
>to around the world about Chaney's claims, I, and presumably you, would
>have to conlude that Mr. Chaney doesn't show much knowledge of biology.
>
>I would go so far as to say he is ignorant of some fundamental areas of 
>biology which are quite important to understand if one is to make claims about
>biological relations to abortion.
>
>Chaney should either read up more on biology before making incorrect statements
>or stop attempting to discuss human biology and fetal development.   
>
>-- 
>David Knapp                                      University of Colorado, Boulder
>Highly Opinionated, Aging  and                      knapp@spot.colorado.edu
>Perpetual Student of Chemistry and Physics.
>            Write me for an argument on your favorite subject.
Newsgroups: alt.birthright,alt.abortion.inequity,talk.abortion