DNA – who’s the boss?

DNA – who’s the boss?

Society and us

Have you ever been in a room full of people and just felt pressured to act in a certain way? Like you had to laugh at inappropriate jokes or pretend you like football because everyone else is into it. You kind of kick yourself afterwards, and when you sit down and tell your friends about it, they say I can’t believe you let on that you know something about football; you don’t even watch the world cup.

And you may even consider at that point, hmm, am I even actually ‘me’ when I’m around my friends? Or is this just another conditioned way of acting in order to fit in? It’s a fascinating question, and I’m no psychologist so I won’t tread too far outside my realm of expertise. But one thing’s for sure – on one level society looks seriously complex, and on another, it just seems to work out based on different personalities interacting in seemingly natural ways.

Society, cells & DNA

Now let’s move from human society and interactions to the level of individual cells. How do they function with (seeming/possible) purpose? Indeed, we as observers may call it a liver, but in fact what it is is a bunch of similar-looking cells operating in sync in order to fulfil some specific role that is essential for the functioning of what we call a human. Actually, a human body is a society of cells, some that are more like one another, and others who are different. Some intermingle, and some don’t. They all share the same DNA code, but they just express it differently.

However, unless we endow with some divine power the molecule DNA, it is inconceivable that it is actually the purposive agent of the cell, let alone of the whole organism. More likely is that it is part of the society of the cell, and cells are part of societies of tissues, and so forth up to the organism interacting with its environment. Kind of like Russian dolls. We can find much evidence for this way of thinking. Indeed, a very impressive recent study using state of the art CRISPR technology (Wang et al. 2018), has illustrated this point quite nicely (see here for Science mag summary article). They confirmed what a number of biologists have been pondering for the last decade. That is, if you move a gene to a different location in the nucleus, this affects its expression, and consequently cellular function also. This only adds to a number of growing mechanisms by which the cell controls expression of DNA.

The crunch

The significance of this cannot be overstated, for it requires a fairly dramatic conceptual shift. It turns out that DNA is not bossing the cell or organism about. Rather, the cell is calling the shots. (Where the purpose of cells or organisms comes from is another question for another day.) I imagine it like a society, where conformity is the rule. Organisms keep up with the Joneses, as do their organs, tissues, cells, and DNA. If DNA could self-reflect, as we are able, it may consider that I’m moving to this part of the genome because I wish to, however, in reality, it is being manipulated by a cell with a seemingly bigger purpose. (You may be scaling this up in your mind and thinking that my suggestion would be that humans possess no free will but are merely conditioned. To that, I would answer that we have different conceptions of what constitutes free will. But again, that is a topic for another day!)

So, for any fellow biologists out there who have tirelessly worked their way through Alberts’ molecular biology of the cell textbook during their undergraduate endeavours, I’d like to say first of all, well done! It’s a big book. Secondly, it is one thing to have conformed to the course syllabus and to have such wonderful data in your hands and to know that protein x interacts with that RNA y. However, it is another thing entirely to consider who calls the shots, and I would urge you to think about that (because it’s seriously fun).

References

Wang, Haifeng, Xiaoshu Xu, Cindy M. Nguyen, Yanxia Liu, Yuchen Gao, Xueqiu Lin, Timothy Daley, Nathan H. Kipniss, Marie La Russa, and Lei S. Qi. 2018. “CRISPR-Mediated Programmable 3D Genome Positioning and Nuclear Organization.” Cell, October. https://doi.org/10.1016/j.cell.2018.09.013.