Okay, we’re back. Inspector Rabbit was about to talk about the signal recognition particle.
Yes, I was pointing out how, on several levels, life is built around these internal tensions, where one need is being played against another need. Then, at the very interface of these tensions, we find solutions that are remarkably elegant and ingenious. The SRP extends this theme of elegance.
Here you have this relatively simple system, composed of three parts, that not only solves the problem of building life around lipid membranes and proteins, but also carries out multiple complex functions. Imagine you are a muscle cell and need some more insulin receptors in your membrane. Okay, so you express the insulin receptor genes and start translating this genetic information into a receptor. When the first part of the receptor under construction is made, it carries a pattern of amino acids that function as a signal, in effect saying, “Hey! I belong in the membrane.” It is the SRP that scans for this very signal. When it finds it, it binds to that signal and it is this binding which then triggers the other elements of the SRP to put the ribosome in pause mode. The SRP then helps the ribosome dock to a membrane tunnel in which it can resume protein synthesis. This tunnel will then facilitate the insertion of the insulin receptor into the membrane.
Oh, so you are saying it is so complex it must have been designed?
No, no, no. We’re not talking about what must have been designed, as I don’t know of anything that must have been designed. And we’re talking about a relatively simple system. This is not an example of a complex mix of parts giving rise to a simple function. This is a simple mix of special parts that give rise to multiple functions needed for life. That’s elegance.
Yeah, but elegance is a subjective call.
As are most calls. Yet keep in mind that I didn’t invent this assessment. Those who work with the SRP on a daily basis are impressed with its elegance. And what’s more, the system is so elegant that we can rather easily deconstruct the system in terms of its function. It can be reverse engineered. This deconstruction helps us to see that the PAUSE step can be skipped without collapsing the functional network, an important consideration when it comes to the difference between prokaryotic and eukaryotic cell plans.
So you are saying this system is so elegant it could not have come into existence without design?
No. I am focused on gathering clues and following up hunches. I’m Inspector Bunny, not Peter Gappin Cottontail. And built into the core of life is a simple, elegant system that radiates rationality. You can bask in it. It is, of course, possible that the blind watchmaker strung it together, yet the signature feature of the blind watchmaker is the kluge.
Kluge? Isn’t he a Swedish actor?
Funny, One With Glasses. A kluge is some messy conglomerate that just happens to get the job done in any way that it can. Throw some junk at the wall and whatever sticks, go with it. If the blind watchmaker cobbled the SRP together, it was a rather lucky blind watchmaker.
Not only did a kluge-making mechanism stumble upon an elegant solution, it was so elegant that billions of years of constant subsequent tinkering could not find a better solution anywhere. When you’re coming up with a solution to a problem off the top of your head that not only works, but works such that no one else can come up with a better solution after billions of years of looking, you are one lucky inventor.
But natural selection is not about luck! Dr. Dawkins tells us this all the time.
Yes, but luck does comes into play when relying material that happens to be laying around. Luck does come into play when getting the solution right from the very beginning. Either it’s extraordinary luck, or someone has been rigging the whole game. But it doesn’t stop with this ancient, universal, elegant device. It turns out this SRP would come in very, very handy when it comes to other evolutionary events much later on. So much so that we might say evolution would have produced a rather mundane living world without it’s lucky find.
Hold that thought, Inspector Bunny. As we need to take another commercial break. We’ll be back with Inspector Bunny and the Luck of the Blind Watchmaker.