Well put, Kyle. I had a professor that would say he was putting some “ew-ah” figures on the board–those are number so big that when you hear them you exclaim, “ew” and “ahhh”! Well, I used to make a big deal about how many different possible proteins 100 amino acids long you could get with the 20 amino acids found in nature. The answer is calculated as 20 x 20 x 20… all the way to 100, i.e., 20 to the 100th power which equals 1.27 x 10 to the 130th power. How big is that number? Well, according to a leading biochemist named Creighton in 1993,
“Just one molecule of each of these proteins, if they were packed together in the most efficient manner, would fill the [known] universe 10 to the 27 times!”, I’m not sure how he gets that but there it is in print in Proteins: structures and molecular properties By Thomas E. Creighton, W. H. Freeman and Company, NY, 1993, p. 106
I know what your are thinking, “ew” and “ahhh”!
Of course, the universe was much smaller in 1993…
So I looked for specific proteins of about that length that were highly conserved in nature, i.e., had the highest % sequence homology being the most distantly related species, like between humans and yeast (still a eukaryotic cell), like the H4 protein of histones, and argue that the chances of that protein coming about by chance are so astronomically low as to prove the need for intelligent design, i.e., God.
Well, there’s a couple things wrong with that argument. Sure, if that was the only protein that could fit the bill, then yes, I think that would be a pretty good argument. BTW, no one knows why (according to the link above) that the H4 histone protein is virtually invariant across species. Its one of the proteins that allows DNA to coil and so is found only in eukaryotic cells, per se, which have a lot of DNA. And it, thus, plays a pretty critical role in allowing more DNA in those cells than simple circular plasmids and other arrangements of DNA in bacteria cells.
One of the things wrong with that argument, however, is that there may be an ocean (not literally, but enormous number) of totally unrelated protein primary structures (linear amino acid sequences) that could have the same shape (assuming shape alone was the critical thing), even though once that sequence is encoded in the DNA it remains invariant. For example, imagine you have a big hollow plastic key, like a kid’s toy key. Protein specificity is often described as a lock and key type mechanism. Now image a thin string a couple feet long would fill that key if pushed through a hole in the hollow key. How many different way do you think you could push that string into the key and never have it fold the same way twice? It would probably be and endless number of times. Or lets just say you’d be saying “ew” and “ahhh” before we ever reached the same way twice. Yet, for every one of those endless times, the string folded in the exact same critical key shape.
So, there is nothing to say that the proteins that exist today had to have linear sequences like they now do–an ocean or maybe a galaxy of other primary sequences could form the same shape. Of course it isn’t just shape that matters but the position of + and - charges, hydophobic regions, hydrophilic regions, steric hinderances, etc., possess by the different amino acids and their properties. But, the analogy still applies.
Note that there are multiple carbonic anhydrase protein enzymes that have almost no sequence similarity because they evolved independently.
There is also the fact that the key evolves along with whatever “lock” it fits into, in our analogy. So, there is nothing to say that the key has to fit a particular “lock” that exists today.
So, you are exactly right, Kyle.
I didn’t see the weakness in these former ID theory-related arguments of mine until I saw and was convinced by the new molecular evidence for evolution.