In efforts done by origins of life studies, the simplest protocell that could be the source of living cells as we know it should contain DNA (or RNA), proteins & enzymes, all enclosed in a membrane. As simple as it may seem, this system, however, includes an advanced communication system. In the previous article, Origin of Life: Irreducible Complexity within the Cell we discussed the chicken-egg problem in that protocell. Now we will discuss the information evolution problem within this protocell, and generally in life as we know it.
As per Webster’s dictionary: information is “the communication or reception of knowledge or intelligence.”
In any communication system we find the core components: sender, receiver, communication medium, and the message or information to be communicated. Information is something imposed over the medium. It’s using the medium but it’s not the medium.
Example: someone sent a message through morse code to another one, who broadcasted it over radio signals, which was heard by another one who transferred that message to an end user through mobile call, which was finally broadcasted through TV. The message or the information was sent multiple times using different materials. However, the information itself is non-materialistic.
Similarly any software – which is an algorithm of saved instructions – is totally non-materialistic. Software is always running on top of hardware and relying totally on the hardware when communicating information or instructions between different nodes to perform certain functions. These nodes could be persons using the software or could be non-conscious machine parts that are programmed to send and receive information. The point about software is that: it’s designed and coded by human intelligence.
Keeping these definitions in mind will help in the next part.
When looking at the DNA, most scientists like Richard Dawkins, Paul Davies, and John Lennox – regardless of their beliefs – admit that the DNA is a real code string.
- Molecular sequence in DNA is not trivial or repetitive information (like ACACAC or GTGTGT, etc)
- As DNA is a very long string of nucleotides, it could store an immense amount of information
- The information within DNA is not merely Shannon information, but it’s meaningful and functional information
- There’s great resemblance between the DNA codes, and computer software programs
- There’s also great resemblance between the biological information flow and any modern IT communication system.
DNA alone is not enough for life without being part of a context or a system that can read the embedded code and translate that into functional proteins in a process called translation. This exists in all life forms regardless their complexity:
- each 3 DNA nucleotides or letters (called codons) translated through mRNA into 1 amino acid (out of 20 possible types)
- a strain of a minimum of 50 amino acids are called Proteins
All scientists today know that protein molecules perform most of the critical functions in the cell. Proteins build cellular machines and structures, they carry and deliver cellular materials, and they catalyze chemical reactions that the cell needs to stay alive. To accomplish this critical work, a typical cell uses thousands of different kinds of proteins. And each protein has a distinctive shape related to its function, just as the different tools in a carpenter’s toolbox have different shapes related to their functions. So Proteins look like the hardware used by the DNA software. The more complex the software is, the more complex is the hardware.
- The average size of a protein increases from Archaea to Bacteria to Eukaryotic (283, 311, 438 respectively)
- The rate of protein synthesis is higher in prokaryotes than eukaryotes and can reach up to 20 amino acids per second
- Viruses typically encode (from DNA) a few to a few hundred proteins, archaea and bacteria a few hundred to a few thousand, while eukaryotes typically encode a few thousand up to tens of thousands of proteins
- It has been estimated that the average-sized bacteria contains about 2 million proteins per cell. Smaller bacteria contain fewer molecules, on the order of 50,000 to 1 million. Yeast cells have been estimated to contain about 50 million proteins and human cells in the order of 1 to 3 billion.
- A short protein of 150 amino-acids can have 20150 = 1.4 x 10195 possible combinations.
Definition of design: The purposeful or inventive arrangement of parts or details. Or simply: the purposeful arrangement of parts.
All scientists agree that life appears to be designed, even if some reject the design idea calling it an illusion, trying to find other alternatives. For example, Dawkins R. 1986. The Blind Watchmaker. New York: Norton.
- P.1 “Biology is the study of complicated things that give the appearance of having been designed for a purpose”
- p.21 “we may say that a living body or organ is well designed if it has attributes that an intelligent and knowledgeable engineer might have built into it in order to achieve some sensible purpose, such as flying, swimming, seeing … any engineer can recognize an object that has been designed, even poorly designed, for a purpose, and he can usually work out what that purpose is just by looking at the structure of the object.”
In fact, the information system within life seems to be not just a product of engineering, but brilliant engineering.
- Communication within life appears to be designed like a fully integrated information system:
- Within the cell itself, between different parts
- Between organs
- Information flow within living organisms is bottom-top and top- bottom as well
- Analogy between the information flow within the cell and any modern IT communication system:
- DNA is Quadruple digital system (A, C, G, T), while in IT systems, it is mainly Binary (0, 1)
- Codons (3 letters) , vs data bus in IT (8-bits, 16-bit, 32-bit, 64-bit, depending on the system)
- start and stop codons, vs. header bits in IT standards to indicate the start and end of a message.
- The synchronization between senders and receivers within the cell implies a preexisting design, like:
- codon length & DNA quadruple system to produce enough possibilities (64), versus the produced amino acids (20). If a smaller codon was used, we will have only 16 possibilities. That’s a mathematically pre-designed system.
- The length of coded genes, mRNA and length of functional proteins, are all matching together. That’s an additional design aspect.
- The “analog” 3D shape of protein which is critical to perform the required function depends on the amino acids formed by digital DNA codes. It is like any digital to analog converter. That requires a fully designed end-to-end system, correlating the desired function with the software codes in DNA.
- Reversely, not every mutation in DNA or software random modification can lead to meaningful or successful protein, as functional protein formation is extremely rare (1 correct sequence for each 1077 incorrect sequence – as mentioned by the molecular biologist Dr. Douglas Axe in his studies), thus the software code in DNA should be extremely precise to match the hardware (reference 7)
As evolution can’t explain how the first information system in life evolved (as mentioned in the previous article), Origin of life (or Abiogenesis) scientists made some trials to explain how information within cell might have evolved, however they are far away from reaching any possible explanation, and it all relies on imagination without observed experience supporting this imagination. Some of the hypotheses:
- self-replication: that will lead to trivial information, while life is surely non-trivial, even in the simplest known or assumed form.
- Pure chance: which is mathematically extremely improbable and was rejected later.
- Necessity or Biochemical predestination, which was rejected as well as it leads to very simple information
- Prebiotic natural selection, which is a self-contradicting hypothesis about the source of information, as it requires the existence of information in the first place so that natural selection can favor it
- RNA world hypothesis, which still lacks the source of information – the source of the meaningful arrangement of nucleotides – within this primitive RNA, even if it is capable of partial self-replication. This will be discussed in the following articles in detail.
The alternative idea is that information in life is really designed.
- We never observed any communication system to evolve on its own. There’s always design and intelligence behind.
- We infer design whenever parts appear arranged to accomplish a function or purpose, and we see definitive purposes and functionalities within cells and living organisms a lot.
- Based on the analogy with computer codes and IT systems, it is more logical to think that this was intelligently designed, like what we do in computers and IT networks, than to just “imagine” a complete communication system – software & underlying hardware – emerging by itself out of nowhere.
Abiogenesis can’t explain till now how information evolved, nor how that advanced communication system within cells came into existence by natural processes.
Based on observations, it’s more logical and scientific to conclude that information in life is the result of Intelligent Design.
To read more about the “Origin of Life” series check: Darwin and the Origin of Life , Origin of Life: Irreducible Complexity within the Cell and What Is Life .