In 1968, the USA had half a million men in Vietnam. The Army needed lots of docs to take care of them and their motto was “If you can practice medicine outside the army, you can practice it inside the army”. There was no 4F for docs, nor were there medical excuses. There were excuses for individuals of exceptional value, and as chemists, you should know where this arose (see the starred footnote at the end of this post if you don’t). This meant that all newly minted MDs would spend two years during or after residency training in the service.
Fortunately (for me) the Army was short of neurologists in 1968, so with just one year of residency (instead of the usual three) under my belt, I was sent to one of their best hospitals (Fitzsimons) to work under an excellent and seasoned neurologist (Col. Halbert Herman Schwamb — whose name alone scared the hell out of me).
The tour of duty in Vietnam was one year for everyone, so docs who had been there for their first of two years got their pick of where to go for their final year. Naturally, Fitzsimons was one of their top picks, so the place was full of them.
What in the world does this have to do with molecular biology? The army had something called the ‘body count’ which meant the number of Viet Cong (and possibly civilian) bodies they could find. It gave a number, which was increasing with each passing month. It showed we were winning. However, not one of the returning two-year docs I talked to (and I talked to a lot of them) thought we were winning. Most thought we were losing, and badly. They were, of course, right. The point is that what we could not measure was far more important than what we could.
Consider the following terms from molecular biology: nonsense codon, noncoding DNA, Junk DNA. Two of them are downright pejorative. All imply that anything in our DNA not coding for an amino acid going into a protein is unimportant. As most of you probably know, the four bases of DNA (A, T, G, and C) are read in groups of three (these are the codons) giving 64 possibilities. The 3/64 not coding for an amino acid are called nonsense codons. They tell the protein making machinery (the ribosome) to stop and start on another protein. The 3 codons are just as vital for life as the other 61, or we’d just be one big protein. Calling them nonsense always seemed peculiar to me.
Noncoding DNA means DNA which doesn’t code for an amino acid going into a protein. The implication is that it doesn’t code for anything else. Of our 3.2 billion positions in DNA, perhaps 2% codes for amino acids going into proteins. The rest has been called ‘junk DNA’ — again the implication is that it does nothing.
You have doubtless heard that we are 98.5% chimpanzee. What this means is that our proteins are 98.5% similar (e.g. they have the same sequence of amino acids in 98.5% of positions). Again, the proteincentric view is dominant here—proteins are all that you have to know.
Now, we all love chemistry or we wouldn’t be here reading this. Consider Independence Hall and Monticello from the chemical point of view. They’re both made of bricks, and a chemical analysis of them could certainly figure out that one set of bricks came from South Jersey and the other came from the Virginia piedmont. However, the most sophisticated chemical analysis can not tell us why the two buildings look so different.
Why not? Chemistry can’t deal with the way the bricks are put together. You can do a lot with bricks if you stack them just right (and the chemical nature of the bricks doesn’t matter very much for this).
However, for at least 30 years, minor differences in proteins were thought to determine the differences between a man and chimp. In fact, it was seriously stated at one point, that chemically man and chimp weren’t different enough (as far as their proteins were concerned) to be considered separate species.
Well, we are, and the determining difference lies in the 98% of the DNA which does NOT code for protein. In some way (which we are just beginning to find out) it determines which protein is made where, how much of it is made, and when it is made. Molecular biology is definitely still in the hunter gatherer stage at this point.
That’s enough for now. The details are emerging and including things like epigenetics, microRNAs, RNA interference, and even in bacteria metabolite control of mRNA translation into protein (look up the work of Breaker at Yale if you’re interested).
**The answer is Henry Mosely who died at age 27 in the battle of Gallipoli in 1915. Moseley used X-ray diffraction to show that each element has an atomic number. With this tool he was able to fill the six remaining gaps in the periodic table (at the time) and to put some order into the rare earths. After that, the British (and everyone else) decided that brains like that shouldn’t be used as cannon fodder.
At my father’s recent 79th Rutgers reunion ( yes his 79th ! ) I met an 87 year old graduate. I asked him where he served in the war (because just about every male in his generation did). He said that he didn’t. I asked him how come. The answer — “I was making penicillin for Merck.”