Wednesday, May 21, 2014

Common Creationist Complaint: How could mutations create all of the information in DNA?

Common Complaint: How could mutations—accidental copying mistakes (DNA ‘letters’ exchanged, deleted or added, genes duplicated, chromosome inversions, etc.)—create the huge volumes of information in the DNA of living things? How could such errors create 3 billion letters of DNA information to change a microbe into a microbiologist? There is information for how to make proteins but also for controlling their use—much like a cookbook contains the ingredients as well as the instructions for how and when to use them. One without the other is useless. See: Meta-information: An impossible conundrum for evolution. Mutations are known for their destructive effects, including over 1,000 human diseases such as hemophilia. Rarely are they even helpful. But how can scrambling existing DNA information create a new biochemical pathway or nano-machines with many components, to make ‘goo-to-you’ evolution possible? E.g., How did a 32-component rotary motor like ATP synthase (which produces the energy currency, ATP, for all life), or robots like kinesin (a ‘postman’ delivering parcels inside cells) originate? [1]

 Logical Fallacies:

  • Straw Man fallacy (in using flawed metaphors, it claims that evolution says something that it doesn’t and then dismisses it – the “goo-to-you” reference, the “cookbook” reference);
  • Argument from ignorance (just because the author doesn’t understand mutations and how they could result in life as we know it doesn’t mean that scientists don’t)

Answer: To understand how mutations are responsible for the DNA we have, you have to understand how complex genetics is. A thorough breakdown of this would require an entire semester course in genetics (which I highly recommend), but it can be explained relatively simply.

DNA doesn’t only code for individual proteins; it has sections that dictate how an entire body is “planned out” (HOX gene); it has sections that are for “regulating” what happens once they get copied, often resulting in a completely different product; some sections are there as “padding” to protect the “important” DNA from getting cut when they get copied (telomeres); there are even transposons, colloquially known as “jumping genes” – genes that regularly move around in the chromosome! Add to all of this that knowledge that sections of DNA are not discrete; a single sequence could play a role in a dozen different genes as they overlap, all of which have different purposes, some with multiple purposes.

Once you understand how complex genetics is, and you also understand that mutations not only include changing DNA “letters” (nucleotides) but also deleting genes or other entire sections of DNA, even inverting chromosomes, it becomes very easy to see how one change can result in a significant difference. A nucleotide change in a HOX gene can result in an organism that looks completely different; a nucleotide change in a regulating gene can result in a completely different editing path for a copied protein; a mutation inside a transposon can have effects all over the chromosome.

Mutations are not “errors;” they are changes. Mutations may be “known” for their destructive effects, but that’s largely due to popular media. Scientists know better. Most mutations go unnoticed and are called “neutral” mutations. According to the National Center for Biotechnology Information, there is an overall average of 128 mutations per human zygote! That means that any given child has over 100 mutations that makes them uniquely different from their parents. Neutral mutations occur because there’s a lot of redundancy in the genetic code in order to prevent major changes from being expressed or “seen.” If a mutation isn’t expressed, it’s “neutral” and ignored. If it is, it is either negative, which are selected against, or positive, which selected for. If neutral mutations keep occurring, then they will eventually become expressed.

Additionally, the negative-ness or positive-ness of the mutations is usually quite minimal. Extremely negative mutations often result in a miscarriage. Additionally, what may often be seen as a negative mutation may actually be a positive one. For example, most people think of sickle-cell anemia as being a negative mutation. However, the allele for sickle-cell anemia evolved in Africa, and Africa is highly susceptible to malaria. As it turns out, carrying an allele for sickle-cell anemia makes one immune to malaria, whereas carrying two alleles would result in having sicle-cell anemia. Carrying one allele is much more common than carrying both. Therefore, in countries where malaria is prevalent, this mutation would actually be beneficial as it would prevent malaria infections.

Comparing the genetic code to a cookbook is assuming design. Cooking is goal-oriented. You want to make a cake, so you follow a cookbook. Evolution isn’t goal-oriented. It doesn’t say, “I want something with wings” and then makes the mutations necessary. Mutations occur; if they are beneficial, there will be positive selection; if not, there will be negative selection. That often results in very complex biological processes because there could have been an “easier” way, a more “efficient” way, for that same thing to happen.  We talk about DNA as if it is a code, but a code implies a message designed to convey particular information. You have a message you want to say, so you create a code to do it. But in DNA, the message comes after the code is written, and if the message is beneficial, then the code is beneficial and will propagate in future generations.

Evolution does not "scramble" existing DNA information. Evolution itself doesn't do anything to DNA directly. It just determines whether or not the DNA present is beneficial in that environment. The key here is that evolution works with what DNA is present. So the answer to how evolution can create seemingly irreducible systems like they describe is that it uses what was already present in the cell. The individual steps for complicated biochemical pathways all served other purposes before they were incorporated into the more complicated path. The same goes for "nano-machines" like bacteria flagellum and the ATP synthetase; each component of these previously served another purpose in the cell. We have discovered the evolution of these systems and structures; far from being proof against evolution, they have provided firm evidence for it.

The problem with the "goo to you" argument is not only that it is a straw man fallacy, but that there are many aspects of our biology that one could argue is "goo to you." For example, the "goo" of ejaculate eventually forms every human being, but no one takes issue with that. And technically, humans are mostly water, and one could argue on a philosophical level that humans have never left the "goo" stage.

[1] 15 Questions for Evolutionists. Evolution: the naturalistic origin of life and its diversity (The General Theory of Evolution, as defined by the prominent past evolutionist Kerkut; see introduction to Origin of life) by Don Batten

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