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Introduction
Dr. John Ankerberg: Can you quickly review with us what James Watson and Francis Crick discovered in the 1950s that would revolutionize molecular biology?
Watson and Crick on DNA
Dr. Stephen Meyer: Well, Watson and Crick made a striking discovery in 1953, which is that they were able to elucidate the structure of the DNA molecule. By that time, many scientists were suspecting that DNA had something to do with the transmission of information or hereditary information. And Watson and Crick were able to figure out what DNA looked like, how it was put together. And that suggested that it was an information carrying molecule.
Crick’s sequence hypothesis
And five years later, Francis Crick formulated something known as the sequence hypothesis. And that was the idea that along the spine of the DNA molecule, along the interior of that double helix, there are chemical subunits, and those subunits are known as bases or nucleotide bases. And Crick postulated that those nucleotide bases are functioning like alphabetic characters in a written text, digital characters, like zeros and ones in a section of machine code. And chemists today identify those four digital characters in the DNA with the letters A, C, G, and T.
How much information is in DNA
Dr. John Ankerberg: How long can that be?
Dr. Stephen Meyer: A typical gene for building roughly one protein is about 1,000 base pairs, or 1,000 of those digital characters. But in our bodies, we have about three billion base pairs or digital characters, the nucleotide bases, that either build for proteins or process and direct the processing of that information. So there’s actually a hierarchical arrangement of information in living cells where you have some information telling other information when to turn on and off.
Dr. John Ankerberg: And the people that are watching, when they look at this thing of DNA, first of all, how many cells are in the human body?
Dr. Stephen Meyer: Well, there’s trillions of cells in the human body. And every cell has information stored in DNA, which is part of a larger information storage, transmission, and processing system that does not just equal our own digital information processing systems that we build in high tech digital computing, it vastly exceeds it in its storage capacity and sophistication.
Specified complexity
Dr. John Ankerberg: There’s a lot of information on a DNA molecule. Explain what is called the sequence hypothesis.
Dr. Stephen Meyer: Yes. So, Francis Crick formulated this idea of the sequence hypothesis in 1958. And the basic idea was that the chemical subunits along the spine of the DNA are functioning like alphabetic characters in a written language, or digital characters, like the zeros and ones in a section of software. Which is to say what gives those parts of the DNA and the DNA molecule as a whole its function, its ability to direct the construction of proteins, is not anything about the physical properties of the chemical parts of DNA, per se, but rather it is their arrangement, their specific arrangement in accord with an independent symbol convention, which was later discovered, and is now known as the genetic code.
So, you have a genetic text that is translated by a genetic code. And what was actually discovered was a complex information storage, transmission, and processing system inside every living cell of every living organism.
The thing about the information in DNA is that the arrangement of those bases, those nucleotide bases, the chemical subunits, is critical to function. So when we think about DNA, we do not just have a complex arrangement of characters, or a random arrangement of characters. What we have is a complex arrangement. It is not something where you have repetition of the same characters over and over again, like a mantra or like a crystal of salt where you have NaCl NaCl. Instead, what you have is a very irregular arrangement, a complex arrangement, which is nevertheless highly specific in order to perform a function.
So, in the information sciences, we make a distinction between complex sequences, which would be kind of a random gibberish, and specified complex sequences, which is what we have in DNA. So it is a very special kind of information that we associate with only two other things in all of human experience. One is written language, and the other is machine code, or digital code.
Software analogy
And so we have the same kind of information in DNA, which in our experience always points to a designing intelligence. Bill Gates has said that “DNA is like a software program, but much more complex than any we have ever created,” and he is absolutely right. But software comes from a programmer, and written text comes from writers. And so, when we find this type of information, known as specified complexity, inside a living cell, we are very justified in inferring that a designing agent played a role.
Dr. John Ankerberg: Everybody out there has a computer. If somebody comes over and says, “Hey, let me just kind of dink around with your code,” and they change it a little bit, what would you say to that?
Dr. Stephen Meyer: Well,
Dr. John Ankerberg: You would say no way.
Dr. Stephen Meyer: It does not work. I ask this question hypothetically when I give talks at universities, and programmers always laugh. You know, if you start changing the arrangement of a functioning section of software by chance,
will you build a new program, or will you destroy the function? And you will destroy the function of the existing code long before you ever get to a new program or operating system.
Dr. John Ankerberg: Your computer will not work.
Closing note
(Continued in Part 2)
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