This is the second post in a series reviewing Perry Marshall's Book Evolution 2.0, Breaking the Deadlock Between Darwin and Design. To see the first post with links to each article in the series, start here.
In Perry Marshall's book Evolution 2.0, chapter 7 is titled "Why the Genetic Code Is a Code, Not Merely Like a Code"
In this chapter Marshall explains that the genetic code is literally a symbolic language, just like binary code is a symbolic language. He tells stories of atheists debating him online who try claiming that the genetic code is not really a code, but instead, simply seems code-like. While biologists all agree the genetic code is a code, in my own work teaching genetics and evolution I've also seen laypeople try to downplay the significance of the genetic code in a similar manner. I sympathize with Marshall's frustration. This is an important chapter in his book.
For those of you who are not familiar with the genetic code, you'll find it worth while to take 5 minutes to watch this animation called "What is DNA and how does it work?". In it, you will gain a fundamental understanding of how the code operates.
Marshall's claim in this chapter that the genetic code literally counts as code is absolutely correct. The genetic code truly is a symbolic language. Every three letters in a gene sequence act as a symbol which a ribosome reads and translates into an amino acid. In the code chart below, for example, we see that GGG codes for glycine (highlighted in blue). About this Marshall writes:
Note that GGG is not literally glycine, because the GGG nucleotides never end up in the glycine. Instead, the nucleotides merge back into the original DNA strand after it is read. GGG are the symbolic instructions to make glycine. The cell’s machinery reads these instructions and obeys them. (Perry Marshall, Evolution 2.0 page 56)
In summary, while there are many things I disagree with in the book, Marhsall's claim in chapter 7 that the "genetic code is a code, not merely like a code" is completely accurate. Biologists have accepted this and have been teaching it since 1961 when the first codon was discovered by Nirenberg's group. The genetic code fits every requirement of a language. In this case the language allows for communication between three types of RNA: messenger RNA (as shown in the animation), transfer RNA (not shown in the animation), and ribosomal RNA.
This is the second post in a series reviewing Perry Marshall's Book Evolution 2.0, Breaking the Deadlock Between Darwin and Design. To see the first post with links to each article in the series, start here.
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