If all that stuff is Greek to you, then the last sentence should be the take home message. It will be a long time, if ever, before embryonic stem cells pan out as any therapy.
Posted on 04/24/2006 9:18:43 PM PDT by neverdem
For three billion years, life on earth consisted of single-celled organisms like bacteria or algae. Only 600 million years ago did evolution hit on a system for making multicellular organisms like animals and plants.
The key to the system is to give the cells that make up an organism a variety of different identities so that they can perform many different roles.
So even though all the cells carry the same genome, each type of cell must be granted access to only a few of the genes in the genome, with all the others permanently denied to it.
People, for instance, have at least 260 different types of cells, each specialized for a different tissue or organ, but presumably each type can activate only some of the 22,500 genes in the human genome.
The nature of the system that assigns cells their various identities is a central mystery of animal existence, one that takes place at the earliest moments of life when the all-purpose cells of the early embryo are directed to follow different fates. Biologists at the Broad and Whitehead Institutes in Cambridge, Mass., have now delved deep into this process and uncovered what seems to be a crucial feature of how a cell's fate is determined, even though much remains to be understood.
They have discovered a striking new feature of the chromatin, the specialized protein molecules that protect and control the giant molecules of DNA that lie at the center of every chromosome.
The feature explains how embryonic cells are kept in a poised state so that all of the genome's...
--snip--
This, after all, is what determines the identities of the various cell types central to an animal's existence. "We are just beginning to get a glimpse of how that central mystery plays out," he said.
(Excerpt) Read more at nytimes.com ...
If all that stuff is Greek to you, then the last sentence should be the take home message. It will be a long time, if ever, before embryonic stem cells pan out as any therapy.
It seems...I don't know...miraculous?
And the NYT thinks its on to something?
If you can understand this article, then you know that embryonic stem cells are going nowhere fast, IMHO.
It puts us one step closer to being able to activate a line of cells, perhaps for each individual, which will go on to do a particular thing.
The example I am considering is teeth. Once you lose a permanent tooth, you have lost something very valuable indeed, and not just to a Tooth Fairy.
If your Dentist could cultivate a new tooth in the lab, grown from skin samples you provide, it would be able to replace your missing tooth without rejection.
Delusions of immortality aside, having a nice smile and healthy mouth would be a blessing for everyone.
I think it's still pretty early in the knowledge curve to be making predictions like that.
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Not sure why you say that. I don't pretend to be a molecular biologist. But understanding the mechanism by which embryonic cells are converted to typed cells and by which typed cells stay that way seems to me to be the first step in two things:
1. Understanding how to take embryonic stem cells (and maybe adult) and convert them into, say, liver cells.
2. Taking, say, a liver cell and undoing the typing and converting it back into an untyped, embryonic cell.
Either way, you are talking about pretty fundamental stuff that could easily revolutionize the future of medicine.
I don't read anything in the article that says the findings are that everything is fixed and nothing can be changed by mankind in the typing of cells. Or do I misunderstand the article completely (a possibility I hold open. If you are a molecular biologist, I would be eager to clear up my misunderstanding).
I think it's still pretty early in the knowledge curve to be making predictions like that.
The sooner that the molecular biology of embryology is understood the better. The problem with any leading edge research is that the researchers don't know what they don't know. Eureka moments are relatively rare. Gaining new and useful knowledge usually takes a lot of work just to make a small advance.
Yep, this stuff all happened by random chance. Thats the ticket. That makes sense. Geeze!
I am not sure that understanding this article (as written) proves anything about the future of embryonic stem cells.
First of all there appear to be several errors so that I am not sure how well the writer understood his subject matter. For one thing the earliest multicellular animals, the sponges began around 800 million years ago. Multicellular fungi and plants began more than a billion years ago. Second, the article talks about cells influencing genes, whereas in fact it is the genes that influence the cells.
I am currently reading "The Ancestor's Tale: A Pilgrimage to the Dawn of Evolution" by Richard Dawkins, 2004. It is a fascinating read, and shows the order in which common ancestors separated out into the various phyla. It sure has changed since I studied biology, and of course it is molecular biology which has made the difference. For example scientific examination of genes shows that camels, pigs, deer, hippos and whales belong to one group, and elephants and manatees belong to a completely different group.
Scientists are finding and doing amazing things with this new knowledge. Many of our genes are extremely old. For example there is a gene called aniridia in humans (affects the iris of the eye), small eye in mice, and eyeless in fruit flys. It is the same mutated gene, although it has slightly different bad effects in each of the three animals. Researchers took an eye gene from a mouse and inserted it into the leg of a fruit fly. Guess what happened? Did the fly leg start to grow a mouse eye? NO it did not. I started to grow compound fly eye tissue. Even though the gene was from a mouse. This switching on and off of different activities has all sorts of promise and possibility.
I don't think at this stage we can really say what is or is not possible with cell regeneration. Dawkins in his book repeated pointed out that he was making educated guesses on when certain branchings in the tree of life took place, but that in another year or two the answer would probably be known.
From the last sentence of the article:
"We are just beginning to get a glimpse of how that central mystery plays out," he said.
I think it is the height of presumption to expect serendipitous discoveries. From the ENIAC to modern computer techology, it's been a long, hard slog. Having high hopes for quick embryonic stem cell results strikes me like playing the lottery with other folks' money, not to mention the ethical problem. If they are bound and determined to spend taxes for regenerative medicine, let them figure out limb regeneration with salamanders after limb amputation or expand on stem cell research other than embryonic.
Thanks for the ping.
BTTT
Exactly, right now in the biological sciences we're not even to the equivalent of paper tape...
Having high hopes for quick embryonic stem cell results strikes me like playing the lottery with other folks' money, not to mention the ethical problem.
I don't know that anyone is banking on quick results, but I do think the research needs to be done.
I see. I misread your post. I thought you were suggesting there was something technical in the article that, those who actually understood this stuff would realize doomed embryonic stem cell research.
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