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The mere presence of Junk DNA represents a potential layer of unnecessary complexity. This makes the job of deciphering the function of each gene just a little
by jostmey 13y ago
The mere presence of Junk DNA represents a potential layer of unnecessary complexity. This makes the job of deciphering the function of each gene just a little harder. While there is much debate about how much of our own DNA is junk, there is little doubt that a considerable amount of it is just junk.
There are also cases where molecular machinery in our cell is repuprosed to carry out novel tasks unrelated to its design. The first example that comes to mind are the voltage-gated potassium channels. These proteins are usually involved in the electrical signalling of the nervous system. Why the voltage-gated potassium channel Kv1.3 functions as part of the immune response in T-cells makes no sense to me. Yet this voltage-gate potassium channel is an indispensable part of the cascade of events underlying the immune response. Another example of a protein with numerous and possibly unrelated functions is p53.
And then there is of course the example of the laryngeal nerve. This nerve makes an unnecessary loop down the neck and then back up to the larynx. This odd quirk is especially exaggerated in the giraffe. Why this is so makes no sense.
The best explanation I have to such weird design quirks, which exaggerate the complexity of biological systems, is that Evolution as a process has no regard for complexity.
- pixl97 13y agoWhy the laryngeal nerve is the way it is makes much more sense if you look at is as a series of trillions and trillions of little tiny steps. At some point a very long time ago vertebrates had very different designs from the contemporaries. As they evolved from strange filter feeders in to jawed creatures, this nerve extended itself longer and longer as creatures with a neck came in to existence. The important thing to see here is the lengthening of this nerve didn't cause selection pressure against it. If any vertebrate animals did develop other, more efficient, nerve routing, it did not give them an advantage to survive unto this day. None of the things we are calling quirks were quirks far back in the past. They have been 'stretched' by billions of iterations. It would be complex, by all definitions of the term, if not impossible to put DNA and all the cellular functions in any semblance of order that would make sense to a person. If evolution has regards for anything, it is survival. No other metric, be it efficiency or complexity, matters unless you produce offspring that produce offspring.
- atmosx 13y agoYesterday I stumbled across a quote from Francis Crick which enhances your view actually: God is a hacker not an engineer. But since there is a huge lack of understanding at this point in time about the DNA junk sections, the p53 protein, the formation of the protein's quaternary structure, the K channels it's hard to accept an answer as definitive.