Tuesday, November 12, 2013

Not-so-junky DNA

Artistic rendering of DNA.  Image source.
DNA is, of course, critical to life as we know it.  It contains all of the instructions necessary to develop a single cell into a fully-functioning adult.  More specifically, DNA codes for proteins, the miniature machines that do all the work in your body.  The code is written using four nucleotide bases: adenine (A), thymine (T), guanine (G), and cytosine (C).  These make up the "rungs" of the ladder shape of DNA.  With the assistance of proteins, each gene (section of code) on the DNA in a cell nucleus is copied to RNA, a shorter, single strand that carries the information outside the nucleus.  Proteins called ribosomes then "read" the RNA strand, matching an amino acid to each set of three nucleotides, forming a long chain of amino acids.  The chain then goes through an elaborate series of twists, folds, and coils to form a functioning protein with a particular job.

As the human genome was decoded over the last decade, geneticists found something interesting about our DNA—only three percent of it appeared to code for proteins.  Due to evolutionary assumptions, the other 97% was thought to be useless leftovers from our evolutionary past, so it was labelled "junk DNA."  Creationists, meanwhile, maintained that most of it still served some unknown function, such as regulating how often certain proteins are made.  As the DNA of other creatures was sequenced, we found that the "junk" parts of our DNA were almost identical to those in other creatures, which should not happen if they indeed had no function.  This led geneticists to reconsider their assumptions that junk DNA consisted of evolutionary scraps.

Now, a recent study (original publication requires subscription) further supports the creationist position that every part of the genome plays a role.  Researchers at the University of California, San Diego found strong evidence that portions of the DNA strand formerly considered "junk" actually play a role in gene regulation.  Furthermore, they found that these regulation sites don't necessarily regulate the adjacent gene, but they can affect a gene much farther away.  Scientists have previously found that non-coding sections of DNA serve as docking sites for proteins that read and copy DNA.  The sites discovered in this study appear to affect RNA splicing, a process in which parts of a newly-made RNA strand are cut out and the strand is rejoined.  This new knowledge, the authors claim, may impact development of treatments for numerous diseases including autism and some cancers.

Though evolution is seen as foundational to biological sciences, we can see here that evolutionary assumptions actually hindered medical advancements until operational scientific analysis revealed the truth.  Contrary to claims by evolutionists such as Richard Dawkins and Bill Nye, belief in the evolutionary model of the past is not required to do accurate and useful scientific research.  Technology advances independently of our views of the origins of life and the universe.

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