Richard Dawkin’s Gene Analogy

përshëndetje skeptics,

I have recently started to read Richard Dawkins’ book, The Greatest Show on Earth, in Which Dawkins summates all the evidence available for evolution, and puts it in a book, trying as best as possible to explain evolution to somebody who does not agree with it. It is a very interesting book to read, with plenty of interesting examples from nature and analogies, which have enhanced my knowledge of evolution and how to explain it to others.

While I was reading, I came across an analogy which I just had to hear, which answers a question often raised in rebuttal to evolution. When talking with a creationist, the idea that genetic diversity cannot occur often comes up (in contrast to the genetic diversity of the human species from just 2 humans? But that’s another story). They say that in a population, genetic diversity cannot occur. They make an analogy with genes as paint. If you take a species, which ranges in colour from red to blue, and you go about procreating, every time you mix two animals, you will only get closer and closer to purple, and genetic diversity will shrink. Eventually, all you will be left with is purple. How can evolution happen if it works like that.

Dawkins argues that evolution does not work like this. In fact, it works quite differently. He proposes that instead of mixing paint, it is best to imagine evolution as shuffling cards. This is how evolution works, and the evidence is right in front of us.

By imagining evolution as card shuffling, it is much easier to get the idea of evolution. Instead of animals being created by mixing of paint, it is more like they are having two decks of cards shuffled together. In this way, instead of just ending up with a disgusting purple mess, you end up with the world as it is today.

This can be used to explain our tweaking of the canine species. Say for some reason a breeder wants to lengthen the tail of Labradors. When he does it, he picks the Labradors which have the most ‘long tail’ genes (cards), and goes about creating a new species. By isolating these dogs with longer tails from the dogs with shorter tails, you can ensure that more and more ‘long tail’ cards remain in the sub-species every time you shuffle the deck.

The logic behind this ‘shuffling and re-ordering’, as opposed to mixing, is actually pretty clear and is presented to us roughly every 5 seconds. When you breed a man and a woman together, one who subscribes to the ‘mixing’ analogy would expect the baby to come out as a hermaphrodite. Instead, this doesn’t happen, we get either a boy or a girl. This is just the mixing of a deck of 1 card. With one card having M on it, and one card having F on it.

Now, imagine this happening with the whole genetic code. Instead of just the one gene for gender (gender isn’t determined by genes, but it makes no difference to the analogy), you have this going on with every single gene in the code. When a baby is being ‘made’, this process will be occurring. Take a single gene in the code. If the mother has gene A, and the father has gene B, the baby will not have a mixture of A and B as their gene, they will get either ‘A’, or ‘B’. This happens all along the code.

Hopefully, I’ve done a good job at explaining this analogy, and haven’t butchered it. That’s all, by shuffling of cards, not mixing paint, with occasional cards falling out of the deck, or 2 being stuck together and coming apart due to plenty of shuffling, you get evolution.

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Random Selection vs Random Mutation

Hey there, skeptics,

I have been in touch with a few creationists recently, who have trouble with the ‘random’ associated with evolution. Today I am going to be explaining the ‘random’ scientists talk about when referring to evolution.

There is a misconception among the public that evolution is a purely random process, that the evolution of species is completely random. This is completely untrue. The evolution of species are not random. There is definitely selection in the process of evolution, and this allows us to predict what type of organisms a specific species will evolve into under selected conditions. In the lab, tests have been done on small bacteria, E. Coli and others, where they have been submitted to a specific environment, say, a shortage of sugar, or an abundance of sugar, and have let the species evolve in the petri dish. Scientists can predict what sort of microbe the E. Coli will evolve into, in this way, evolution is not random.

Evolution is random on the individual DNA order, this is the random that Scientists talk about. In the normal life of any living organism, that organism will undergo the constant replication of genes inside of it. DNA is constantly being copied, but every now and then, there will be a mistake in the copying process. This is called genetic mutation. It is this process which allows for speciation, it allows for this lovely branching of evolution, it allows for these new adaptations to occur in biology. This genetic mutation is random, but rather oxymoronic, this process is not completely random.

Let me explain. In the genetic sequence, there are genes which are extremely important, like the ability to produce sex cells or heart cells or liver cells or brain cells, and there are genes which aren’t very important, like the length of one’s nose. So that the genes which create heart cells or brain cells do not get mutated away, (because they are very important) these genes are highly protected for. The organism creates many copies of those genes, so that even if one gets mutated, the information for building a heart is still there.

Look at it this way, in your body, you will find, say (the numbers aren’t correct, just a demonstration), 100 copies of the genes for making heart cells, were as you will only find a few copies of the gene for controlling how long your arms get. This is so that, in the case that one copy of the ‘make heart cells’ gene gets mutated, there are still dozens more there to back it up. Were as something like height or pigmentation, which is not important to function, but needs to be able to adapt to new circumstances, will only have a few copies of the genetic code.

This is how evolution is not completely random, there are barriers of protection, to stop the species from evolving to radically, and to ensure that the important genes don’t mutate. I will leave you all with a quote from James D. Watson, “Today, the theory of evolution is an accepted fact for everyone but a fundamentalist minority, whose objections are based not on reasoning but on doctrinaire adherence to religious principles”, James Watson, Molecular biologist, geneticist, zoologist and co-discoverer of the structure of DNA.