Friday, November 7, 2014

Weekend Rebel Science Excursion - 37

DNA is not alive
Today we take a look at a persistent false meme which other Agnotology researchers have also taken a looked at.

Regular readers know that Dredd Blog has often repeated the statement "DNA is not alive" and "RNA is not alive" many times over the years.

Who would have thought that the false meme "DNA is alive" is so widespread and believed by so many?

Today, I will venture an educated guess as to why this false meme is so persistent, and how it is associated with the ignorance concerning microbes and viruses.

But first, who would have believed that a percentage of students who incorrectly believe that DNA is alive, and who go to a college or a university that knows better, are still unable to grasp the chemistry - even after those students take university level biology classes that teach them DNA is not alive?

Yes, even after being taught that, why do they still not grasp the chemistry?

Here is a quote from a scientific paper based on a study of the phenomenon:
We are involved in a project to incorporate innovative assessments within a reform-based large-lecture biochemistry course for nonmajors. We not only assessed misconceptions but purposefully changed instruction throughout the semester to confront student ideas. Our research questions targeted student conceptions of deoxyribonucleic acid (DNA) along with understanding in what ways classroom discussions/activities influence student conceptions. Data sources included pre-/post-assessments, semi-structured interviews, and student work on exams/assessments. We found that students held misconceptions about the chemical nature of DNA, with 63% of students claiming that DNA is alive prior to instruction. The chemical nature of DNA is an important fundamental concept in science fields. We confronted this misconception throughout the semester collecting data from several instructional interventions. Case studies of individual students revealed how various instructional strategies/assessments allowed students to construct and demonstrate the scientifically accepted understanding of the chemical nature of DNA. However, the post-assessment exposed that 40% of students still held misconceptions about DNA, indicating the persistent nature of this misconception. Implications for teaching and learning are discussed.
(Research in Science Education, Volume 43, Issue 4, Aug. 2013, cf. Springer). It seems that when we are infected with any false meme, it can persist even after facing a lot of proof to the contrary.

Let's take a look at some statements about DNA that echo the state of science concerning the matter:
"How would you describe what you do?

My laboratory — the Mansy Lab at the University of Trento — builds artificial cells, or cellular mimics. What distinguishes us from other people in this field is that, typically, people begin with something that is already alive and then they try to change the behavior of that already-living thing by changing its genes. What my lab does is a bit different. We start with things that are not alive. So, protein by itself is not alive, DNA by itself is not alive — but somehow, when you put these things together, under the right conditions, you get life. Nobody knows how that is, and so that’s what we’re trying to figure out. I guess you’d say we are exploring the boundary between living and non-living. What does it mean for something to be alive?

So if DNA in itself is not alive, what is it?

It’s just a molecule, which scientists can build in the lab. That was one of the nice things that the Venter Institute showed: you can build an entire synthetic genome, and it’ll function like a natural one." - (More to life than DNA (emphasis added), Sheref Mansy)
"9- DNA is not living. It is a chemical - a large fragile molecule - in fact it is a FANTASTICALLY HUGE MOLECULE and for what it is, it is in fact remarkably robust. It contains a series of chemical bonds linked together in a chain, and since not all the links of the chain are the same, it is possible to store information there. Our modern computers use binary - a code made of two digits - 1 and 0 or ON and OFF or MAGNETIZED and NOT MAGNETIZED. DNA uses quaternary code - 4 digits represented by four proteins.

10- It is non-living; there is no debate in the biological community about this. It is a relatively inert chemical that can now be synthetically made. Considering DNA as living is like considering protein to be living. DNA is part of a living cell, as are proteins, fats and a number of other organic molecules." (Biology Online)
"A molecule is not alive; DNA ... is not alive. The first biological level on which autonomous life appears is the cell." (The Splendid Feast of Reason, p. 128)
Now, on to a couple of the reasons the false "DNA is alive" meme persists.

One paper points out:
We believe that the absence of DNA from evolution instruction helps perpetuate student misconceptions regarding evolution, and the thesis of this paper is that students would understand evolution better if instructors made the genetic basis of evolution explicit at the DNA sequence level—ideally as part of a curriculum specifically designed to correct student misconceptions.
(Nothing in Evolution Makes Sense Except in the Light of DNA, emphasis added). It would be simple to use any of many books to point out:
Although I would be the last person to denigrate, in any way, the exceptional work which went into the discovery and understanding of DNA or the work that continues to this day in exploring this amazing chemical construction it is inescapable that a strand of DNA is not alive; it never has been and it never will be; it is just an organic molecule. Naturally, therefore, we must ask, 'what is the smallest biological structure that is alive? It is the biological construction known as the 'cell'.
(Life on Other Worlds and How to Find It, p.51). Regular readers know that Dredd Blog has pointed out another reason this false meme persists.

That reason is that there is ignorance of abiotic evolution in general, and ignorance about the complexities of abiotic entities:
VI. Virus Ignorance

Again, what I mean by "ignorance" is our ignoring of viruses because they were defined as not alive, not living, and not a carbon-based life form.

Now, we find out that they are by very, very far the greatest population of entities that contain RNA or DNA:
There are an estimated 1031 viruses on Earth. That is to say: there may be a hundred million times more viruses on Earth than there are stars in the universe.
(On the Origin of the Genes of Viruses). It is a no-brainer to realize that it is about a hundred years late that we now begin to study them in earnest ...
(On the Origin of the Genes of Viruses - 3). That post gives six other factors that may have bearing on the false meme at issue in today's post.

As the one paper above (Nothing in Evolution Makes Sense Except in the Light of DNA) indicated, DNA is not even mentioned in a lot of "evolution" classes ("the absence of DNA from evolution instruction helps perpetuate student misconceptions regarding evolution").

Ya think? 

Isn't using "bio" (life) to define "abio" (non-life), i.e. using biology to teach abiology, a bit like "observing adolescents to understand early childhood" -Alex Filippenko ?

Add to that equation the study showing that those who are carriers of the false "DNA is alive" meme still had the meme after one or more evolutionary biology classes.

No doubt the origin of the problem rests in substantial degree with educators who have neglected to focus on abiology (see Weekend Rebel Science Excursion - 27).

Have a good weekend.


  1. Great explanation of the science, Dredd - thanks. The "machine" part is the one that gets people's rankles up. You wanna "break it down?" (cue "Hammer Time")

    Probably have to start with the definition of a "machine."


    1. The definition of "molecular machine" rather than "machine" has been the focus in my posts.

      The science has accelerated and left some behind.

      Google "Dredd Blog molecular machine" and you will get my drift.

      Or go directly to "The New Paradigm: The Physical Universe Is Mostly Machine" and be done with it in one quick read.