December 12, 2005 | David F. Coppedge

Micro-RNAs are Cell’s Optimizers

“Unnoticed next to the main ingredients, microRNAs were considered to be ‘junk’ DNA, leftovers from millions of years of evolution.”  That line comes from an article on EurekAlert telling about how dramatically that picture has changed.  RNA molecules are now seen to be indispensable, with many roles in the cell.  This article talked about how a certain microRNA has a “fail-safe” role in development, preventing birth defects.  Researchers at the University of Florida found microRNA that acts “as protective mechanisms in healthy development not just by strategically turning off gene activity, but by making sure it stays turned off.”  This is one way a hindlimb is prevented from turning on genes that are only supposed to be expressed in the forelimb.
    Another article on EurekAlert claimed that RNAs have “shaped the evolution of the majority of mammalian genes,” but the connection to macroevolution is obscure.  What scientists at the Whitehead Institute for Biomedical Research found is that most genes have microRNAs that regulate them.  These RNAs don’t just switch them on and off; they finely-tune the expression, to help cells achieve the optimum levels of proteins for the tissues that need them.  Many of these microRNAs are “evolutionarily conserved” (i.e., unevolved) from animals as different as humans and chickens.  One researcher noted, “Our genomes have good reason to maintain the microRNA targeting sites necessary for turning down these genes at the appropriate place and time.”

We really didn’t need any of the references to evolution.  Those evolutionists who are desperately trying to understand the origin of life have tremendous headaches with RNA.  While the “RNA World” is the most popular speculation about how life got started, getting from carbon, hydrogen, oxygen, nitrogen and phosphorus to RNA is a big hurdle (07/11/2002)  No plausible prebiotic soup experiment has been able to produce RNA: not the phosphates, not the ribose sugars, not the bases.  Furthermore, no soup of chemicals puts them together into nucleotides – the links on the RNA strand.  And furthermore, even if the soup got lucky and made a nucleotide, there is no known natural mechanism for linking them together into RNA polymers, to say nothing of getting them all one-handed, and in a sequence that could accomplish anything (except self-destruct with the next UV ray or lightning bolt).  OOL researchers look at RNA and DROOL (Darwinist Rambling about Origin Of Life).  Notice how evolutionary thinking about evolutionary junk hindered real understanding of what these molecules were there for.  Therefore, the field belongs to those who see optimized, interrelated complexity functioning with high fidelity and reason, that is well-designed.

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Categories: Cell Biology, Genetics

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