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Re: [Channel-talkbio] Unit 9 Human Evolution

From: Mary Johnston <mjohnston@haverhill-ps.org>
Date: Tue Mar 06 2007 - 11:05:33 EST

 
Hey Karen and Ed,
  Onto the next unit which was evolution. I have always enjoyed this
topic and am still amazed when people try to deny the process of
evolution. I always enjoy reading about how the chimpanzee is our
closest living relative anf facts like there is more genetic variation
within ethnic populations than between the major racial groups. For
example, the online text points out that "if everybody on earth became
extinct except for the Kikiyu of East Africa, about eighty percent of
all human variation would still be present in the reconstituted
species." This is essentially saying that we are all much more closely
related than one might at first think. I think the "Out of Africa"
hypothesis that all modern humans are descended froma Mitochondrial Eve
and Y chromosome Adam who were based in Africa is quite plausible.
There seems to be little evidence to support the idea of pure races. We
are all mixed at some point. It makes me think of the current
presidential election and the controversy surrounding Barak Obama. Some
people think he will have a hard time appealing to blacks and whites
because he has a mixed heritage. Some of his ancestors may even have
owned slaves. This argument is ridiculous on several counts including
that his heritage has no impact on his ability to lead this country and
that everyone at some point in their heritage is mixed.
    I am a proponent for the "Out of Africa" hypothesis which states
that modern humans evolved from a common ancestor who started in Africa
and then spread eventually to the other continents. evolving as
conditions required. The multiregional hypothesis which states that
Homo sapiens populations evolved simultaneously in separate areas like
Africa, Europe, Asia. all at once seems a little too convenient and
current DNA evidence suggests that the Africa model is more probable.
     I found the research on asthma to be quite interesting as well
because my new little niece has been diagnosed with asthma and asthma
seems to be on the rise in this country probably in great part due to
environmental reasons like high levels of pollution. The interesting
finding by researchers was that the genes that were indicators of asthma
were not the same for whites, blacks, and hispanics. My niece has a
white father and a hispanic mother. Obviously I don't know which
genetic markers she has, but it would be an interesting research
project. This idea of major differences between the races in asthma
seems to contradict the idea that races are more similar than they are
different.. The author of the online text tries to explain this by
saying the differences are due to marker allele frequency differences
and not to gene type differences. In other words the alleles that mark
the genes of interest may occur more frequently or less frequently
depending on the group one is analyzing. The text is quick to add that
more research needs to be done in this field before we have a conclusive
answer. In my own opinion, I would think that it would make sense that
although many differences are present, all human beings are
fundamentally more similar than they are different and that probability
and allelic frequency plays a huge role in evolution. Just think about
cases of genetic drift. What do you think about this idea?
Mary Johnston

________________________________

From: channel-talkbio-bounces@learner.org on behalf of
channel-talkbio-request@learner.org
Sent: Mon 3/5/2007 12:00 PM
To: channel-talkbio@learner.org
Subject: Channel-talkbio Digest, Vol 7, Issue 1

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Today's Topics:

   1. Re: Cell Biology and Cancer and Reply to Geneticsof
      Development (Karen Blaustein)

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

Message: 1
Date: Fri, 2 Mar 2007 20:17:22 -0500
From: "Karen Blaustein" <kblaustein@haverhill-ps.org>
Subject: Re: [Channel-talkbio] Cell Biology and Cancer and Reply to
        Geneticsof Development
To: "Discussion list for REDISCOVERING BIOLOGY"
        <channel-talkbio@learner.org>
Message-ID:
 
<69BB75AAB563AB418EEB93D45855D87D0196E2D2@hps-mail.haverhill-ps.org>

Greetings Mary and welcome Ed to our discussions,
Mary I am glad you changed the discussion to cancer, although I find the
subject of stem cells so interesting even though it is so controversial.
After watching the video on cancer it is amazing to me how much
scientists now know about the genes and proteins that control cell
growth. Nevertheless, we still do not have a "cure" for cancer. As
discussed in the movie, it is wonderful that there are so many new and
different treatments for cancer that did not exist 25 years ago due to
our increased knowledge of the cell cycle and the genes that activate
and inhibit cell growth. This subject is very personal to me because my
mother died of cancer at the age of 45. When she was diagnosed at 35 she
was only given 6 months to live, but actually lived another 10 years.
However, she suffered through chemotherapy for most of those years and I
remember her saying how she was hoping to live as long as possible in
hopes of the discovery of a cure for cancer. While watching the video,
I couldn't help but think that if the resources that are available now
were available when she was alive, she might have had a better chance of
surviving the cancer.
As for your question Mary, I think that access to health care is
essential to bridge the gap between the haves and the have-nots. As you
mentioned, I am sure that many people do not trust the health care
system or are afraid of seeking medical treatment. Education is an
important component in the formula. That is why it is important for
students to learn about the causes and preventions of cancer and
understand the cell cycle so they have a better understanding of the
disease and therefore may use this knowledge if needed in the future.
It would be great if a national healthcare system was available.
Unfortunately, economically it does not seem very feasible. I think we
also need to fix our educational economic woes along with our healthcare
system!

Karen

________________________________

From: channel-talkbio-bounces@learner.org on behalf of Mary Johnston
Sent: Tue 2/27/2007 8:43 AM
To: channel-talkbio@learner.org
Subject: Re: [Channel-talkbio] Cell Biology and Cancer and Reply to
Geneticsof Development

Dear Karen,
     I am totally disgusted by someone selling fertilized embryos for
$3000 per embryo. This is the blatant selling of human life. I thought
we abolished selling people in this country quite a long time ago, but
apparently every time we take a few steps forward, we also take a few
steps backward. I realize that a fertilized embryo is not the same as a
fully developed new-born baby, but what else would an embryo ever
become? I know you could take the argument to the extreme and say what
about a sperm or an egg cell? Don't these have the potential to become
a new life? I don't believe so. It is that beautiful moment of
fertilization that makes all the difference. The information and
directions for a whole person are not present until that occurs.
Otherwise, any other point at which we say "Life" has occurred is really
arbitrary such as is it heart development or brain development or the
moment the fetus looks "human"? I know a lot of people would not agree,
but a sperm left alone will never become a human being. An embryo
allowed to develop will and this makes all the difference in my opinion.
      In regard to the chapter on cancer, I was really surprised that
the National Cancer Institute's Budget was 4.6 billion dollars ten years
ago and we still have not managed to beat cancer. I know that there is
a lot of great work going on from tumor suppressor drugs to
anti-angiogenesis factors, but the fact that cancer is still killing so
many of us is a hard pill to swallow. Of particular interest to me was
the fact that cancer death rates differ among different sub-groups of
the population. For example, as quoted in the unit, the 1996
"colorectal cancer death rate was 16.4 per 100,000 for white Americans
and 22.5 per 100,000 for black Americans and that the death rate for all
cancers combined is about 30 % higher for blacks than whites." This
indicates that cancer is ravaging our society and also exploiting
discrimination. Perhaps blacks do not have as easy access to health
care or perhaps they are mistrustful of a medical system predominated by
white male doctors. Perhaps they are more often dismissed as being OK
when early signs of disease should have been caught or perhaps even that
they themselves have a culture of not seeking medical treatment because
they feel they cannot afford it or don't want to be burdensome to their
families. Whatever is the case, I found this to be a disturbing and
unacceptable trend. What can we as a scoiety do to stop this disparity?
Perhaps we need more free clinics that provide public services and
walk-in programs. More importantly, we need a national healthcare
system that provides everyone with equal access to medical care just as
we have a national public school system. I realize that there would be
some problems with this, but just because the situation wouldn't be
perfect doesn't mean that we shouldn't try and attempt beneficial
change. What do you think?
Mary Johnston
  

________________________________

From: channel-talkbio-bounces@learner.org on behalf of
channel-talkbio-request@learner.org
Sent: Mon 2/26/2007 12:00 PM
To: channel-talkbio@learner.org
Subject: Channel-talkbio Digest, Vol 6, Issue 5

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Today's Topics:

   1. Re: Unit 7 Genetics of Development (Karen Blaustein)

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

Message: 1
Date: Sat, 24 Feb 2007 16:51:12 -0500
From: "Karen Blaustein" <kblaustein@haverhill-ps.org>
Subject: Re: [Channel-talkbio] Unit 7 Genetics of Development
To: "Discussion list for REDISCOVERING BIOLOGY"
        <channel-talkbio@learner.org>
Message-ID:

<69BB75AAB563AB418EEB93D45855D87D0196E2CF@hps-mail.haverhill-ps.org>

Hi Mary,
I basically agree with you. It was interesting to learn about the
differences between a totipotent stem cell and a pluripotent stem cell.
I had never heard of a totipotent stem cell, but now realize that they
are the only ones that have the ability to develop into a fetus with the
associated placenta. Personally, I do not believe that we should produce
embryos for the sole purpose of research when other sources of stem
cells are available. These include embryos produced by infertile
couples that are no longer needed due to various factors. Many of these
embryos may be discarded and therefore I believe that these embryos
could be used for research. However there are still many controversial
implications concerning stem cells. Should we ban couples from using
fertility treatments because they will inevitably be producing some
embryos that may never be used? Is this the same thing as killing a
possible life? To me, it basically comes down to this... the stem cells
have not diferentiated into specialized cells. Accordingly, they do not
have nerve cells, brain cells, etc. which are cells assoicated with
thought, feelings, and pain. Similarly, organs have not yet developed.
Therefore, they are not really a living human being yet. Could we dream
up that ovarian egg cells and sperm cells are also a potential person?

I was watching the news the other night and they had a story about a
woman who is making and selling fertilized embryos to the general
public. The cost was about $3000 dollars, which is significantly less
that adoption (except that it was preferably to buy more than one
because implantation might not work the first time). She is making and
selling possible human life. What do you think about this?

________________________________

From: channel-talkbio-bounces@learner.org on behalf of Mary Johnston
Sent: Fri 2/16/2007 10:50 AM
To: channel-talkbio@learner.org
Subject: Re: [Channel-talkbio] Unit 7 Genetics of Development

________________________________

Dear Karen,
      I found this unit on the genetics of development to be quite
interesting and controversial. In terms of research it seems that
embryonic stem cells are the most useful. They can differentiate into
many more cell types. They are easy to grow in large numbers in the lab
and hold much promise in the treatment of many illnesses and medical
conditions including Parkinson's disease, diabetes, and leukemia.
However, in the harvesting of these cells, the embryo and thus a
potential person are detsroyed. Adult stem cells are much harder to
grow in large amounts and cannot differentiate into as many different
cell types. It is my opinion that research on existing cell lines
should continue as directed by the Bush administration, but the
destruction of embryos for the sole purpose of research should not be
allowed. We could be destroying a human being that actually does
discover the cure for cancer or HIV or any number of diseases. At the
same time, we must be reasonable and allow medicine to advance, so those
embryos that are already marked for destruction such as in unused
in-vitro fertilization procedures should at least have some useful
purpose.
     The key to this whole issue really is figuring out how to get adult
stem cells to become pluripotent. I have heard in the news that
researchers are making great strides in this research. Therefore, I
think that in the future the stem cell debate will not be an issue
because scientists will have figured out how to use adult stem cells
more prominently in their research. How do you feel?
Mary Johnston

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Received on Tue Mar 6 11:06:43 2007

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