This time it's an anonymous posting on the premier IDC website, Evolution News & Views [Long Non-coding RNA Punches Another Hole in "Junk Genome" Myth]. The anonymous poster links to a recent paper in Genes & Development that shows a function for a particular long non-coding (lnc) RNA. The paper implies that many of these lncRNAs (up to 400) are expressed in mouse erythroid cells.
Regulatory RNA have been known and studied for at least four decades and various lncRNAs have been characterized over the past twenty years. The IDiot at Evolution News & Views seems to think that this is a new discovery proving that there's no junk in our genome. The facts are quite different.
As I pointed out in my review of The Myth of Junk DNA, the amount of the genome devoted to producing lncRNAs is about 0.1% [Junk & Jonathan: Part 6—Chapter 3]. So, not only have we known about regulatory RNAs for many years, we also know that their genes don't account for very much of the genome, I figure it can't be more than 2% even when you include all of the most optimistic estimates of regulatory RNAs [see What's in Your Genome?].
But the ignorance of the IDiots is much more profound than just being incapable of calculating percentages. The latest posting reveals the depth of their ignorance.
These findings have two important implications. First, non-coding regions of the genome were assumed to be leftover evolutionary relics that no longer play a functional role. The assumption was not due to extensive studies of non-coding regions of the genome, but rather to a commitment to what is known as the central dogma of molecular biology: DNA is transcribed into RNA and RNA is translated into amino acids to make proteins. This was considered the primary purpose of DNA. The non-coding regions were assumed to have no function, and were dismissed as the natural consequence of genetic "junk" accumulating over time. This paper is one among an accumulating corpus of papers discussing new and interesting functions of the non-coding regions of the genome. (See The Myth of Junk DNA by Jonathan Wells for a history of "junk" DNA and additional references describing the function of so-called "junk" DNA. See here for a discussion on the regulatory role of introns.)There was never a time in the past fifty years when knowledgeable biochemists and molecular biologists thought that all non-coding DNA was nonfunctional junk. This was never an assumption of the Central Dogma of Molecular Biology which states that "... once (sequential) information has passed into protein it cannot get out again" [Basic Concepts: The Central Dogma of Molecular Biology]. There are many scientists who have misconceptions about the Central Dogma [The Central Dogma Strawman] but the IDiots go one step farther by misunderstanding the misconception!
We've known about functions in non-coding DNA since the early 1960s as anyone who has ever glanced at a textbook would know. It's hard to tell whether the IDiots are just butt-ignorant of basic science or whether they are lying. This is an especially tricky problem when the silly strawman argument is popularized by Jonathan Wells because he's supposed to know the science [Junk & Jonathan: Part 1—Getting the History Correct] [Junk & Jonathan: Part 2— What Did Biologists Really Say About Junk DNA?].
We know that most of our genome is junk because we know a great deal about genomes, genes, biochemistry, molecular biology, and evolution. We know which parts are likely to be functional and which parts are likely to be broken genes and other kinds of junk. We know this because we understand the subject, not because we are covering up our ignorance.
The IDiots are ignorant of the science and they assume that everyone else is as well. That's a very bad assumption.
No comments:
Post a Comment