Re: [asa] Ethical Considerations in Recent Nature Stem Cell Paper

What if I am a clone?

In parthogenesis, in principal there is no distinctive dna. Nor would
there be (in principal) to a sperm cell "persuaded" to begin the
division process.
These clones are not on the surface distinguishable by distinctive dna.

On the other hand, I have read that the cells resulting from the first
few divisions of a fertilized ovum are not in fact quite identical in
the cellular composition (I don't recall whether that extends to the dna
itself). So, one could argue that even though cells might be teased out
of this early structure, and each might be capable of producing a
distinct individual, they would not in fact develop as exactly
identical. I'm not an expert in this area, so perhaps someone else can
chip in on whether this distinctiveness extends to the dna itself. In
any case, there is also the potential for slight spontaneous or induced
variations in the dna as well. So, in all fairness, the "in principal"
indistinguishable dna may in reality not happen.

On the third hand, we don't think of a particular edition of a book as
being distinctly different if one page in a hundred has some editorial
or editional difference. We often can make out familial similarities in
humans, though subtle and often subjective, but our dna is only the
least little bit (percentage wise) distinctive from one another. Mostly,
we are alike, nearly identical from a dna standpoint. I think we have
had to look pretty hard along the way to identify the markers we use to
define our differences (distinctiveness).

What a knotty problem to sort. The bottom line is probably that we will
always have two communities in tension over these matters.

Don Perrett wrote:

>Thinking out loud as well, does it not seem logical that any lifeform (plant
>or animal, etc) should be consider a self-distinctive lifeform when it has
>it's own dna code? Is that not how we distinguish ourselves within the
>scientific community now? So, if "I" am I and not someone else, because "I"
>have a unique dna of my own, then why should an unborn child not receive the
>same distinctive treatment?
>
>A non-rhetorical question: At what point in embryonic development is there
>a distinctive dna code?
>
>Don Perrett
>
>
>
>-----Original Message-----
>From: asa-owner@lists.calvin.edu [mailto:asa-owner@lists.calvin.edu] On
>Behalf Of Jim Armstrong
>Sent: Wednesday, November 22, 2006 21:48
>To: ASA list
>Subject: Re: [asa] Ethical Considerations in Recent Nature Stem Cell Paper
>
>Just to expand the context for your questions a bit further (but not
>changing the issue), fertilization of the ovum is not a necessary
>precondition for cellular fission. Moreover, if the conditions are just
>right, a sperm cell can be induced to begin the division process as well.
>That brings into question any certainty that is based upon conception in the
>conventional sense.
>
>The flip side of this line of questioning might be to take a serious look at
>the rather large natural attrition that accompanies the reproductive process
>and the ovum and sperm generation/quality. There is a great deal of loss of
>life potential prior to conception (especially the sperm!), as well as
>after. In some ways, one might (?) even conclude that the care provided in
>and through these human-involved processes is good stewardship of an
>otherwise lossy natural process.
>
>The life question itself gets a little muddy as well with the prion
>propensity to reproduce itself, though not alive even in comparison to a
>virus. Of course, the prion hypothesis is a tad muddy in itself at this
>stage of its investigation.
>
>Just thinking out loud........
>
>JimA
>
>jack syme wrote:
>
>
>
>>So the question remains where do you draw the line? Where does life
>>begin? When does one become a person? When does a collection of cells
>>become something more than just that?
>>
>>A blastomere comes into existence after fertilization so why would it
>>have made a difference?
>>
>>How is harvisting cells from a blastomere morally any different than a
>>morula? How is it morally any different than a blastocyst?
>>
>>
>>----- Original Message ----- From: "Rich Blinne"
>><rich.blinne@gmail.com>
>>To: "ASA list" <asa@calvin.edu>
>>Sent: Wednesday, November 22, 2006 3:51 PM
>>Subject: [asa] Ethical Considerations in Recent Nature Stem Cell Paper
>>
>>
>>
>>
>>>A recent paper in Nature
>>>(http://www.nature.com/nature/journal/v444/n7118/abs/nature05142.html
>>>) caused quite a stir by claiming that embryonic stem cell lines
>>>could be created from a single blastomere obviating a need for an
>>>embryo being destroyed. It was later discovered that during the
>>>experiment embryos were indeed destroyed because they extracted
>>>multiple blastomeres from the embryo rather than one at a time.
>>>Nature just published a revised paper and an addendum to the report
>>>in their current print edition. Here's the result from addendum table
>>>
>>>
>number 1.
>
>
>>>Number of embryos used: 16
>>>Number of blastomeres retrieved: 91
>>>Number of blastomeres divided: 53
>>>Number of outgrowths:28
>>>Number of ES cell-like outgrowths: 19 Number of ES stem cell lines: 2
>>>
>>>According to the addendum, the blastomeres were cultured in the same
>>>medium as the parent embryo. Diffusable factors from the other
>>>blastomeres may have increased the possibility of survival of the
>>>resultant ES lines. It appears the breathless press announcements of
>>>an ethical way of extracting embryonic stem cells may have been
>>>overstated.
>>>
>>>To unsubscribe, send a message to majordomo@calvin.edu with
>>>"unsubscribe asa" (no quotes) as the body of the message.
>>>
>>>
>>
>>To unsubscribe, send a message to majordomo@calvin.edu with
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>>
>>
>>
>
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>
>
>
>
>
>

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Received on Thu Nov 23 11:35:55 2006