• Log in with Facebook Log in with Twitter Log In with Google      Sign In    
  • Create Account
  LongeCity
              Advocacy & Research for Unlimited Lifespans

Photo

Human DNA in animal cells [CIRA]


  • Please log in to reply
8 replies to this topic

#1 caliban

  • Admin, Advisor, Director
  • 9,150 posts
  • 581
  • Location:UK

Posted 13 December 2002 - 06:41 PM


:: This Topic Will Follow CIRA Guidelines ::
Read here: http://www.imminst.org/cira



“researchers hope that someday embryonic stem cells might be produced by cloning, that is, installing a patient's DNA into a human egg without a nucleus.” (1)


Now, this scenario is pretty doable today. No problems if you are talking fertile female patients. Otherwise you would have to rely on donor material. A scenario that is a bit further away is

implanting human DNA into eg. a mouse egg for harvesting stem cells

What are your views on:

1) the science?
What role does mitochondrial DNA play? Are there limiting factors?

2) the ethics?
Is it immoral to implant human DNA into an animal cell? Why, or why not?

3) the principle?
Would it not be better to always use donated human eggs? Should this procedure be done at all?

All three questions can be addressed independently.
Looking forward to your contributions!





(1)
Ronald Bailey
New Leases on Life- The promise of regenerative medicine
Reasononline 4.12.2002 -http://www.reason.co.../rb120402.shtml


#2 veronica

  • Guest
  • 36 posts
  • 0

Posted 03 January 2006 - 12:16 AM

1) the science?
What role does mitochondrial DNA play? Are there limiting factors?

I am not sure if mice mitochondrial DNA is identical to human. It could present some risks since it encodes for many proteins. Could it be also more susceptible to damage with age?
How about cross species viral infection? Could this lead to new types of viral diseases?

2) the ethics?
Is it immoral to implant human DNA into an animal cell? Why, or why not?

I do not think it is immoral. I would support it if it saves human life.

3) the principle?
Would it not be better to always use donated human eggs? Should this procedure be done at all?


Yes, I think it would be better to use donated human eggs. But animal eggs are more available than human eggs.
But I think that rejection of these human/animal stem cells might be a problem.

Another idea:
Based on definition, stem cell is undifferentiated cell, capable to differentiate in any type of tissue. Could we eventually differentiate stem cells in germ cells and make human eggs to produce more stem cells?

Or:
We could remove patient own stem cells. Proliferate, de-differentiate, and trans-differentiate them in the another type of stem cells and then reintroduce them back into the patient.

It would be interesting to see if we can control the age of the cells differentiated from these stem cells.

I think once we understand the signals that control and activate stem cells we might be able to live for ever.

Click HERE to rent this BIOSCIENCE adspot to support LongeCity (this will replace the google ad above).

#3 ag24

  • Honorary Member, Advisor
  • 320 posts
  • 29
  • Location:Cambridge, UK

Posted 03 January 2006 - 12:38 AM

I published a short piece on the mtDNA aspect of interspecies NT, explaining why it may be an opportunity more than an obstacle, in RR in 2004:

http://www.sens.org/xenoTC-PP.pdf

I am a bit abrupt about the ethical side there, but I maintain that it shares the qualities of Hurlbut's ANT but more so.

Quite a few people are thinking about this area, but it is so strongly opposed by existing ethical guidelines, even in the UK, that its time may not yet have come.

sponsored ad

  • Advert

#4 veronica

  • Guest
  • 36 posts
  • 0

Posted 03 January 2006 - 06:13 AM

This is a great paper! The third approach is the most interesting one. It seems that mt genes would be more protected in nucleus. These stem cells could be also more resistant to ROS etc. I hope it will be be soon done.

#5

  • Lurker
  • 1

Posted 03 January 2006 - 10:25 AM

1) science

The regulatory RNA from the other species will still be present in the recipient cell.


2) Ethics

strongly opposed by existing ethical guidelines


I suspect that interspecies NT will compound the ethical controversy rather than lessen it. After all, we are talking about the generation of human-animal hybrid ES cells with the same totipotency as human ES cells.

#6 John Schloendorn

  • Guest, Advisor, Guardian
  • 2,542 posts
  • 157
  • Location:Mountain View, CA

Posted 03 January 2006 - 11:11 AM

Based on definition, stem cell is undifferentiated cell, capable to differentiate in any type of tissue. Could we eventually differentiate stem cells in germ cells and make human eggs to produce more stem cells?

Quite possibly [1], [2]. If this indefinite oocyte source could be tapped, interspecies therapeutic cloning might hopefully not remain something that we need to scare our conservative friends with.

[1] Hubner K et al. Derivation of oocytes from mouse embryonic stem cells. Science. 2003;300(5623):1251-6.

[2] Geijsen N et al. Derivation of embryonic germ cells and male gametes from embryonic stem cells. Nature. 2004;427(6970):148-54.

Click HERE to rent this BIOSCIENCE adspot to support LongeCity (this will replace the google ad above).

#7 John Schloendorn

  • Guest, Advisor, Guardian
  • 2,542 posts
  • 157
  • Location:Mountain View, CA

Posted 03 January 2006 - 01:27 PM

Speaking of it, I would like to suggest that the maturation of this technology to a point where everyone could clone their own patient-specific cells with oocytes derived from pre-existing ES cell lines is one of the very few issues in the stem cell field where the cost/benefit ratio would warrant targeted immortalist investment/commitment. Accelerating the advent of an inexhaustible oocyte source would enable every middle class lab to begin human therapeutic cloning experiments on an almost arbitrary scale and thereby boost progress of the whole field. A culture based method might also improve the public image of the field and cut ethics approval times and efforts. Furthermore, the technology can be appreciably accelerated, because current efforts appear low.

Edited by John Schloendorn, 03 January 2006 - 01:42 PM.


#8 John Schloendorn

  • Guest, Advisor, Guardian
  • 2,542 posts
  • 157
  • Location:Mountain View, CA

Posted 03 January 2006 - 01:56 PM

2) the ethics?
Is it immoral to implant human DNA into an animal cell? Why, or why not?

In my view, an action can have moral value only when it affects sentient entities. Interspecies SCNT by itself does not involve such entities and is therefore morally neutral (discounting the hopes that it might later be used save lives and relieve suffering for human patients). If one wants to interdict such a technology, they would need come up with an argument of why it would be immoral, which I might then attack. In a country that values liberty and the pursuit of happiness, it should not be necessary to defend a morally neutral action.
Counting the founded hopes that it may save lives and relieve suffering, it would become morally imperative to do it and publicly support it, although I do not know how founded these hopes are at this time.

Click HERE to rent this BIOSCIENCE adspot to support LongeCity (this will replace the google ad above).

#9 caliban

  • Topic Starter
  • Admin, Advisor, Director
  • 9,150 posts
  • 581
  • Location:UK

Posted 04 January 2006 - 04:26 PM

Thanks veronica for picking up in 2006 a question from 2002, thus illustrating again the superiority of forums over email lists: Nothing gets lost. Strangely enough I might be involved this year in a project on "hybrids and chimera".

Thanks Aubrey for another challenging paper. I have to digest that carefully first.

Meanwhile, things appear to have moved, in (dare I say it) China and Korea:
Human into Rabbit: Chen et al. Cell Res. 2003 Aug;13(4):251-63.
Human into Cow: Chang et al. Fertil Steril. 2003 Dec;80(6):1380-7

In the west nowadays people -including 1998 pioneers Advanced Cell Technologies Inc- seem to consider inter-species NT primarily in the context of saving endagered species. (Which makes no sense to me. Jurrasic Park -yes, but endagered species?)

There was a nice general review in 2004 by the ISCCR's Suzanne Kadereit
Nuclear transfer (nt)ES cells: A first step towards therapy?




1 user(s) are reading this topic

0 members, 1 guests, 0 anonymous users