MASHing junk DNA.

The Korean War lasted from June 1950 to July 1953. It served as the basis of the 1968 book MASH: A Novel About Three Army Doctors by Richard Hooker (pen name of former army surgeon H. Richard Hornberger), describing the experiences of surgeons at a Mobile Army Surgical Hospital during the war. This was adapted into a film (MASH) starring Donald Sutherland in 1970, which in turn inspired the TV series M*A*S*H starring Alan Alda.

The finale of the television series M*A*S*H remains one of the most-watched episodes in the history of the medium, with more than 100 million viewers. By that time, the series had spanned 251 episodes over 11 seasons from 1972 to 1983. The Korean War, by contrast, lasted three years.

What does this have to do with junk DNA?

As I have been attempting to show by referencing the scientific literature in a series of Quotes of interest, there was a diversity of views on the functional significance of noncoding sequences of all sorts before and after the terms “junk DNA” and “selfish DNA” were introduced. In fact, it is clear that the default view for many authors was adaptationist and therefore that noncoding elements must have a function by virtue of their very existence. Not knowing the function of noncoding DNA stimulated, rather than stifled, research in this area. Also, it is clear that Ohno (1972) had minimal impact at least up to the time when the selfish DNA hypothesis was proposed (1980), because at that time the assumption of function was still pervasive — that’s why selfish DNA was presented in the first place, as an alternative to strict adaptationism. Moreover, two other points must be borne in mind: 1) introns, pseudogenes, satellite DNA, and various kinds of transposable elements were not characterized, or indeed in some cases not even discovered, until at least the late 1970s, and 2) the tools necessary to study noncoding elements, most notably DNA sequencing, did not arise until the late 1970s and early 1980s.

In other words, the most common assumption at least up to 1980, made on the basis of Darwinian adaptationist logic, was that most or all noncoding DNA was functional, and the tools for testing functional (or non-functional) hypotheses about noncoding DNA were not available until the 1980s. What this indicates is that the only period during which one could possibly argue that noncoding DNA was dismissed when it should have been studied begins around 1980. As I have tried to demonstrate, there was intense interest in noncoding DNA, much of it related to searches for function, during the 1980s. (Note: I have not even begun to discuss the history of thoughts about possible functions, or at least effects, of total DNA content on the cell, which traces to the 1870s.) Nevertheless, in 1989 or 1990 there is a switch in the discussion to claiming that noncoding DNA had long been dismissed as inconsequential junk, first in scientific review papers, and then in science news stories beginning by 1994. We have been told ever since that scientists long neglected noncoding DNA. Creationists have expanded this to include the absurd and supremely illogical argument that “Darwinism” is at fault in this, even though Darwinian adaptationism was the basis for assuming that noncoding DNA must be functional from the time noncoding sequences were first identified.

To summarize, then, there was a period of about 9-10 years during which it is conceivable that noncoding DNA could have been ignored when it should have been studied as biologically relevant. The period of telling us that it was ignored but is now thought to be important, by contrast, has been going on for about 18 years and shows no signs of abating. Nevermind the fact that there was no such period during which functions were not postulated and tested, or the fact that the originators of the ideas of junk DNA and selfish DNA unambiguously noted that a non-trivial portion of noncoding sequences would be functional for the organisms carrying them.

M*A*S*H was entertaining, thought-provoking, and served as a statement about the horrors of war in general. It is really just an interesting afterthought that it lasted nearly four times longer than the war on which it was based. The repetitive claim that scientists have long ignored noncoding DNA, on the other hand, serves no function and refers to a period of history that never actually happened.

Leave a Reply




You can use these HTML tags

<a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>