Jennifer writes, “It’s the RNA world hypothesis, but I took a little poetic license and used DNA instead of RNA just because I thought double stranded would be more aesthetic.”
Carl: Here’s an article I wrote for Discover about the RNA world hypothesis for how life got started. And another for Science.
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"Celebrated curiosity monger"
Carl Zimmer writes about science regularly for the New York Times and magazines such as Discover, where he is a contributing editor and columnist.
He is the author of twelve books, the most recent of which is Science Ink: Tattoos of the Science Obsessed. His website is carlzimmer.com and his address is blog at carlzimmer dot com .
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December 12th, 2008 at 11:01 pm
[...] of them is flourishing over at Carl Zimmer’s science blog, The Loom. Here’s a big, one, RNA World. It’s semi-accurate but [...]
March 22nd, 2010 at 3:54 pm
On RNA Cell Faring Programs
The chicken and egg story…
RNAs are still Earth’s primal organisms, who made the genome as their functional working templates…(BTW, they also made the cell enclosing membranes as their functional organs…)
Cell Faring Programs Involve Transcription Factors,
Made By RNA Genes From DNA Templates Made By The Genes,
Transcription Factors That Activate Genes,
The RNA genes.
A. TGF-beta acts as a transcription factor
http://www.answers.com/topic/tgf-beta
Transforming growth factor beta (TGF-beta) is a protein synthesized by skeletal cells, found in most species, that controls proliferation, cellular differentiation, and other functions in most cells.
B. Myc produces DNA binding protein
http://www.answers.com/topic/myc-2
myc = Any of a group of vertebrate oncogenes whose product, a DNA binding protein, is thought to promote the growth of tumor cells. Possibly from my(elo)c(ytomatosis virus).
C. From “How Cells Protect Themselves from Cancer”
http://www.sciencedaily.com/releases/2010/03/100316101653.htm
- Two protection programs work together, through an interaction with normal immune cells, to prevent tumors.
- The oncogenes themselves can activate these cell protection programs in an early developmental stage of the disease. They trigger apoptosis (programmed cell death), and senescence (biological aging) is triggered by another oncogene, the ras gene. Senescence stops the cell cycle, and the cell no longer divides.
- First Myc oncogene triggers apoptosis in the lymphoma cells. The dying cells attract macrophages of the immune system, which devour and dispose of the dead lymphoma cells. The thus activated macrophages secrete messenger molecules (cytokines), including the cytokine TGF-beta, which can block the growth of cancer cells in the early stage of a tumor disease, by switching on the senescence program.
D. From “Red and white blood cells come from different sources” ???
http://www.sciencenews.org/index/generic/activity/view/id/56929/title/Researchers_distinguish_two_different_types_of_blood_stem_cells_
Researchers (in mice) distinguish two different types of blood stem cells??? All stem cells are not created equal???
- In the blood, millions of diverse cells die every second. To keep up with this loss, stem cells continually divide to create the correct balance of cell types, which include oxygen-carrying red blood cells and a menagerie of immune cells.
- The hitherto thought was that one single type of blood stem cell in the bone marrow continually replenish the blood system throughout a person’s life. Recent studies hinted that blood stem cells have distinct behaviors, but the different kinds of cells were pinpointed only now, using different dye stain markers.
- While each type of stem cell was able to produce every kind of blood cell, the team found a clear difference in end-products ratio: One type of stem cell produced many more red blood cells than immune cells, and vice versa.
- What’s more, as the mice aged, the relative amounts of these stem cell types shifted. As mice got older, the stem cells that create more red blood cells made up a larger proportion of all stem cells, beating out the immune-cell–biased stem cells.
- The researchers also observed that TGF-beta1 spurs red blood cell–producing stem cells to divide and at the same time represses division of their immune cell–producing counterparts. They suggest that these different actions of TGF-beta1 may allow fine-tuning of the ratio of different stem cell “subtypes”.
Dov Henis
(Comments From The 22nd Century)
03.2010 Updated Life Manifest
http://www.the-scientist.com/community/posts/list/54.page#5065
Genomes Are RNAs-Made Patterns-Manuals
http://www.the-scientist.com/community/posts/list/260/122.page#4819