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Our future, our universe, and other weighty topics


Friday, March 2, 2018

Why You Won't Ever See a Flesh-and-Blood Dinosaur

The Jurassic Park series of movies has been wildly successful. When such a movie series is seen by so many people, its underlying premise can work its way into our minds as a settled fact. In this case that's a shame, because there are very strong reasons for suspecting that the underlying premise of the Jurassic Park movies is not correct. There are very strong reasons for believing that we will never be able to recreate protoplasmic dinosaurs by discovering some bit of dinosaur DNA, and then leveraging that to create dinosaurs.

The basis premise of Jurassic Park was presented in a cute little animation near the beginning of the first movie. The animation depicted an insect that bit a dinosaur, and then got stuck in gooey amber, while a drop of dinosaur blood was still in its body. The amber then solidified to rock-like hardness, preserving the drop of dinosaur blood. The idea was that scientists then extracted the dinosaur's DNA, which they then used to create a flesh-and-blood dinosaur.

Such a scenario has an underlying assumption that was never explicitly stated in any of the movies: the assumption that the body plan of an organism is specified in the organism's DNA. Under this assumption, if we can find the DNA of a dinosaur, then we have all the information we need to recreate the dinosaur.

The idea that the body plan of an organism is stored in the DNA of its cells is a widespread assumption. But there is no proof that this assumption is correct, and there are very good reasons for believing that it is not correct.

The first reason is that the “language” used by DNA is a minimalist feature-poor language lacking any grammar or capability for expressing anything like a blueprint, a recipe, a program or an algorithm for making an organism. The language used by DNA is pretty much the poorest, most “bare bones” type of language you can imagine. It's a language unsuitable for purposes other than stating lists of chemicals.

For DNA to be able to specify a body plan, the language used by DNA would have to support either one of these two things: (1) a three-dimensional specification similar to a blueprint, specifying how particular parts fit together and are related to each other from a positional standpoint, or (2) a set of sequential instructions specifying how to build a three-dimensional structure, something similar to the complicated assembly instructions that come with do-it-yourself unit of furniture. To the best of our knowledge the simplistic little “bare bones” language used by DNA is utterly incapable of such sophisticated forms of expression.



MINIATURE LANGUAGES
NAME LIST OF WORDS IN LANGUAGE WHAT CAN BE SPECIFIED BY LANGUAGE WHAT CANNOT BE SPECIFIED BY LANGUAGE
Sandwich Language Bread, Turkey, Ham, Cheese, Lettuce, Tomato, Onion, Bacon Various types of sandwiches Anything that is not a sandwich
Exercise Language Jump, Crouch, Stretch, Punch, Lift, Bend, Squat, Spin Various types of exercises Anything that is not an exercise
DNA Language Alanine, Asparagine, Aspartic acid, Arginine, Cysteine, Glutamine,
Glycine, Glutamic acid, Histidine,
Isoleucine,
Lysine,Leucine, Phenylalanine, Methionine, Serine, Proline,
Tryptophan,Threonine, Tyrosine, Valine
Polypeptide sequences – a linear sequence of amino acids Anything that is not a polypeptide sequence, including the 3D shape of a protein, the shape of any body part, the body plan of any organism, or a behavior or instinct.

One of the simplest data structures you learn about in computer science is a stack. A stack is like a stack of cards in which each card has one particular piece of information. Complex hierarchical data cannot be represented with so simple an arrangement.

To get an idea of why DNA cannot store body plans, imagine you  have twenty boxes on a table. Each box has a particular type of card, and on each card is printed some part of a house. So there's a box full of cards each showing a single glass pane, and another box full of cards each showing a brick, and another box full cards each showing a wood beam, and another box full of cards each showing a tile, and so forth.

Now imagine you are trying to create a specification of a very complicated mansion. But you cannot lay the cards out on the floor. All you can do is put the cards in a single stack. You would quickly realize the impossibility of such a task. A one-dimensional thing such as a stack cannot represent complex three-dimensional information. For the same reasons, the stack that is the DNA molecule cannot be storing three-dimensional body plans.

The second reason for thinking that body plans are not stored in DNA is that even if DNA somehow did contain the extremely sophisticated instructions necessary for expressing body plans, there would be nothing in the human body capable of interpreting such instructions. It is never sufficient merely to have instructions capable of specifying some complicated output. You also need to have an instruction interpreter sophisticated enough to read those instructions and produce the complicated output. We know of nothing in the body that could be capable of creating three dimensional body outputs using any three-dimensional body plans if they happened to exist in DNA.

The third reason for thinking that body plans are not stored in DNA is that we have not discovered evidence that DNA stores either algorithmic information for constructing a human body, or any type of three-dimensional blueprint specifying the structure of a human body. For example, we have particular parts of DNA storing proteins used by the eye, but no part of DNA that lays out the very complicated three-dimensional structure of an eye.

A fourth reason for doubting that body plans are stored in DNA is that if body plans were stored in DNA, we should expect that the size of an organism's DNA should be proportional to the size and complexity of an organism. For the same reasons that the blueprints of a skyscraper use much more paper than the blueprints for a house, under a “DNA has the body plan” assumption we should think that the human DNA is much bigger than the size of, say, any flowering plant. But astonishingly, the opposite is true. The chart here shows the relative size of the DNA in different organisms. We see that the size of the DNA (in base pairs) in mammals is much smaller than the size of the DNA of many amphibians and flowering plants. We see on this logarithmic chart that the DNA of some amphibians and flowerings plants holds ten times more information than the DNA of humans. This discrepancy is know as the C-Value Paradox.

A related comparison is the number of genes in the DNA. According to this link, rice has between 32,000 and 50,000 genes, while humans have only about 20,000 genes. That's the opposite of what we would expect if DNA stored body plans.

These reasons powerfully argue that DNA does not store the body plan of a complex organism such as a human or a dinosaur. On page 26 of the recent book The Developing Genome, Professor David S. Moore states, "The common belief that there are things inside of us that constitute a set of instructions for building bodies and minds -- things that are analogous to "blueprints" or "recipes" -- is undoubtedly false." Biologist Rupert Sheldrake says this about this issue:

DNA only codes for the materials from which the body is constructed: the enzymes, the structural proteins, and so forth. There is no evidence that it also codes for the plan, the form, the morphology of the body.

''A gene makes a protein and that's about it,'' states biologist Brian Goodwin. ''It doesn't tell you how proteins interact, how cells and tissues communicate, how organs come into being, how an immune system forms, or how evolution works.'' 

In a 2016 scientific paper, three scientists state the following:

It is now clear that the genome does not directly program the organism; the computer program metaphor has misled us...The genome does not function as a master plan or computer program for controlling the organism; the genome is the organism's servant, not its master. 

The myth that DNA stores a complete blueprint of an organism is actually six levels removed from reality. To show that DNA stores a complete blueprint for an organism, you would have to establish this chain of assertions:

  1. You would need to establish that DNA actually specifies the three-dimensional shapes of proteins.
  2. You would need to establish that DNA specifies a blueprint for particular cells.
  3. You need need to establish that DNA specifies a blueprint for particular tissues.
  4. You would need to establish that DNA specifies a blueprint for particular organs.
  5. You would need to establish that DNA specifies a blueprint for particular organ systems.
  6. You would need to establish that DNA specifies a blueprint for particular organisms.

None of these things have been done – not even the simplest one, the first of these six. Scientists have been trying for decades to solve what is called the protein folding problem, the problem of how proteins get their 3D shapes. It has still not been proven that such shapes are determined solely by the linear sequence of amino acids in the proteins. DNA does not even seem to specify the 3D shapes of a protein molecule. How could it, when the impoverished DNA language doesn't have any capability for stating three-dimensional positions?

If DNA does not store the body plan of an organism, we will never be able to resurrect dinosaurs by using some recovered dinosaur DNA. Nor will it be possible to ever create a flesh-and-blood dinosaur through any possible artificial manipulations of DNA. We may have great fun in parks filled with robotic dinosaurs, but they won't be flesh-and-blood organisms like us. 

If you see this, you'll know it's a robot

Whether we will be able to resurrect dinosaurs isn't all that interesting a question. A far more interesting question raised by these questions is the fundamental question: where are the body plans of organisms stored?

The answer we must give to this question is: we don't know. We have every reason to suspect that the secrets of life are far deeper than the average biologist suspects, and that we are far very indeed from uncovering such secrets.

Imagine a little child who is given a palm-sized digital device. The child may make simplistic assumptions about the device, such as the idea that all of its functionality is contained inside it, and that the device stores every item that the child sees when she uses the device. But the truth is vastly more complex. The device is connecting with a grand mysterious external infrastructure that the child knows nothing about : the Internet.

Similarly, life itself may involve a mysterious connection with some grand cosmic information infrastructure utterly beyond our current understanding. Somewhere within such an infrastructure may be stored the body plans of organisms that cannot be expressed by the poor man's language of DNA, with its impoverished vocabulary of 20 nouns (all chemicals).

The absurdity of calling DNA “the secret of life” (as if it had all the information needed to explain an organism) becomes clear when we consider that an organism is something vastly more than just a body plan. Every organism is a continuous symphony of operations needed to maintain the organism. Just as you don't explain the music coming from the performance of a symphony by just giving a physical specification of the musical instruments and an orchestral seating plan, a body plan would never explain the biology going on inside an organism. DNA not have the body plan of the organism, nor does it have the information for the fantastically complicated interactions needed for the organism to keep living.

Rather than being "the secret of life,"  DNA must be only one of many secrets of life.  Some of the most important of those secrets have not been discovered.  We still have not discovered the secret of life that might explain where body plans come from and how they are stored.

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