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Carl Zimmer Carl Zimmer is the author of several popular science books and writes frequently for the New York Times, as well as for magazines including The New York Times Magazine, National Geographic, Science, Newsweek, Popular Science, and Discover, where he is a contributing editor. Carl's books include Soul Made Flesh,, Parasite Rex and Evolution: The Triumph of An Idea. His latest book is Smithsonian Intimate Guide to Human Origins. Please send newsworthy items or feedback to blog-at-carlzimmer.com.
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The Loom
November 03, 2004
The Morula Solution?Email This EntryPrint This Entry
Posted by Carl Zimmer

morula.gif It's obvious from yesterday's vote that embryonic stem cells will continue to split the country (California versus Washington DC, for one thing). But in an ironic bit of timing researchers at the Reproductive Genetics Institute have just published some results at Reproductive BioMedicine Online that could--possibly--short-circuit some of the arguments against using embryonic stem cells.

The RGI researchers have figured out how to derive stem cells from a four-day old embryo--a stage known as a morula. Until now, scientists have been using older blastocysts, and have been destroying them in the process. But when the RGI team took a single cell from a morula, it still had the capacity to develop into a normal embryo. That means that parents who are doing IVF could conceivably agree to have a cell removed from their morula, which could then give rise to a line of stem cells, while the morula developed into an embryo ready for implanting. The stem cell line could be banked for therapy, or used for research.

I first read about this in an article published yesterday on News@Nature.com (unfortunately the article requires a subscription). Neither the article nor the abstract I linked to makes it clear whether this could be a viable source of stem cells for the large-scale research that scientists really want to do. But the results are enough to inspire a thought experiment.

Let's say you object to stem cell research because each blastocyst is a unique human being with a unique genome and the capacity for life. Destroying one is therefore murder. Would this "morula method" be acceptable to you? It seems like it has the benefits of adult stem cell research (no controversry over destroying embryos) and the benefits of embryonic stem cell research (the possibility of discovering therapies that can't be derived from adult stem cells). Or does any tinkering with embryos set off alarms? Perhaps we'll find out in a Senate hearing.

Category: General

Jim on November 3, 2004 08:50 PM writes...

Being a reasoning person, this sounds like great news, and I wholeheartedly support it (especially if that cell taken off has more cells taken off when it becomes a morula itself). However, it really doesn't do anything about the crazed evangelical anti-stem-cell argument. As I recall, a cell splitting off from the morula naturally is what brings about identical twins, yes? So, from their perspective, you're still committing murder same as if you've just smashed the morula, or taken a morning-after pill, or any such thing. Once you pull off that cell, you've created a set of identical twins, and then you're killing half of them.

Permalink to Comment
~DS~ on November 3, 2004 08:54 PM writes...

Some of us have brought the potential morula solution up on an evangelical Blog called The Evangelical Outpost. Lotta prolifers there. So far, no comments either way. I'll keep you updated.

Permalink to Comment
Joel on November 4, 2004 11:41 AM writes...

This is not tinkering, it is cloning.

Embryo splitting or twinning is a cloning technique.


The NY Times has a story today about another possible approach to developing embryonic stem cells.

"Sperm Stem Cells Are Grown Outside Body"

"Cultivation of the sperm production cells has been a 10-year goal of Dr. Ralph L. Brinster, a reproductive biologist at the University of Pennsylvania School of Veterinary Medicine. The ability to culture the cells is a first step that leads in a number of possible directions. One is correcting the sperm of infertile men. Another, if ethically acceptable, would be genetic engineering in humans. A third is generating embryonic stem cells without the controversial step of making an embryo."

"At present, embryonic stem cells are taken from the surplus embryos generated in fertility clinics. The sperm production cells have many of the same characteristics of embryonic stem cells and, Dr. Brinster believes, are only a couple of developmental steps away from them. It may be possible to walk them backward into being embryonic stem cells. These could then be converted into the specialized cell types needed to repair damaged organs. "

The PNAS paper is titled:

"Growth factors essential for self-renewal and expansion of mouse spermatogonial stem cells"

Permalink to Comment
Captain Sunshine on November 4, 2004 12:52 PM writes...

I would not agree. I would argue instead that an extraction of some cells from a morula then used to generate a stem-cell line is analogous to donating an organ that then grows back.

If the extracted cell is allowed to develop into a viable embryo, then I would see your argument as more applicable. If that step is circumvented, then I would not agree.


Permalink to Comment
Aaron on November 6, 2004 11:22 AM writes...

I'm a little nervous about the claim that the morula can grow into a normal embryo after a cell has been removed. I mean, you're removing something like 3 to 10% of its mass! How sure are we that this has no effect?

If removing a cell from the morula really doesn't change the development of the embryo, I'm in awe of the morula's self-correcting power. In my opinion, computer scientists ought to be very interested in this.

Permalink to Comment
CJ on November 6, 2004 07:38 PM writes...

"I'm a little nervous about the claim that the morula can grow into a normal embryo after a cell has been removed."

Oh, but it can. This has been the basis of a technique used for screening embryos for genetic disorders prior to implantation. The methodology is referred to as B.A.B.I. (baby) for Blastomere Amplification Before Implantation.

Permalink to Comment
Aaron on November 7, 2004 11:30 AM writes...

"Oh, but it can."

Whoa... that's crazy... How does it work? Does another cell speed up its replication rate to replace the last one? How does it know to?

Permalink to Comment

TrackBack URL: http://www.corante.com/cgi-bin/mt/mt-tb.cgi/6517
Just a Nick from Crumb Trail
California has passed its ESC research funding initiative if we (the taxpayers of California) can figure a way to pony up the $3G to pay for it. But, it may not be needed or even useful. This study describes an original technique for derivation of ES ... [Read More]

Tracked on November 3, 2004 07:21 PM





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