Junk DNA, Junk Memes, Recombination, and Art

rna

[2005] One of my research projects in the late 80s dealt with genetic algorithms. This means you design a simulated system that mimics evolution by natural selection: select an encoding that can be cranked through a constructor to produce a virtual organism, set up an initial population of these organisms and a simulated environment for them to interact with, and let them compete, grow, reproduce sexually, and transmit their more successful combinations of characteristics to the next generation. Over many generations these systems are capable of creating very skillful populations, and the sum of the activities of the population gets more and more optimal in extracting resources from the virtual environment. I learned quite a bit about population genetics from these experiments, and the simplifications inherent in these systems compared to real biology can make apparent what is not so obvious in real life.

Many popular treatments of the topic imply that mutation (a random change in the DNA caused by radiation or chemical accident) is the critical factor in gradual change of the genome over time. This is not really true; as life evolved on Earth, almost all of it using the same encoding (four bases ATCG) and similar constructors, by far the most common source of change became recombination. Within a species population vast changes can occur using only the DNA sequences present in the population as they are sexually recombined in different sequences, changing both in frequency and in function as fragmentary sequences are combined in new ways. But there’s more: viruses can transfer chunks of their DNA into cell nuclei, and vice-versa, and bits and pieces of DNA from one species can be transferred to another this way, sometimes ending up in the mainstream population. So the population of DNA fragments is a sea of words that is shared among all life forms, and we are all related, not only to other humans, but to all life, down to the bacteria. The meanings of these fragments depend on the context in which they occur, and when put together in a new way, the “sentences” of life can say something completely new even when created from old parts.

An organism typically has far more DNA than appears to be in actual use to encode proteins or participate in gene expression. The “unused” DNA is often called Junk DNA, and it was thought to be accumulated in unused areas of the genome over time; now we know that some of it plays a continuing role. But some of the apparently abandoned segments at some point in the past were useful material, which has been swapped by accident into a place where it is masked and dormant. For example, a moth species adapted to a snowy environment is primarily light-colored, but has unexpressed (recessive or switched out) genes for pigmentation remaining from a long-ago era when it was adapted to a dark forest environment. If the territory occupied by this species suddenly changes climate (as has happened many times in the past), the population may find itself struggling to survive when its individuals are now easily picked out against a darker background, and thus subject to a much higher rate of predation. Natural recombination via sexual reproduction will produce a few individuals who are darker, and the much higher survival rate for those individuals means the next generation will have many more of the old pigmentation DNA fragments, will produce even more dark and darker individuals, and by this process over a very few generations can re-express the species’ previous character as a dark-pigmented group suitable for survival in a forest. In this way recessive, and to a lesser extent “junk,” genes are a species memory, providing a library of characteristics from which the species can draw to evolve to suit its changing environment.

Now we bring in a bit of jargon. In complex systems work, we often abstract the system of relationships between parts of a complex system and apply them to a system made up of different parts that, because it is similarly connected, has similar behaviors. The meta level expresses the commonality of behavior of the systems even though they are built on a different substrate.

The term meme was popularized by Richard Dawkins to mean a basic unit of cultural DNA, a fragment of an idea which, when strung together with others in meme-complexes, are the basic units of cultural transmission and replication. He pointed out the similarities between transmission of cultural ideas and genetic information; slightly inaccurate copying, recombination, survival of the fittest, and reproduction leading to similar population “memetics.” As the body of knowledge carried by the population of the world grows and evolves, it, too, carries a lot of “junk memes,” formerly adaptive fragments of knowledge and belief which no longer appear to have value, yet are carried quietly along with the body of the culture.

Some of these memes can do great harm in the modern world — racism, xenophobia, superstition, mercantilism. Those cultures that express them in harmful ways tend to be overwhelmed and die out over time, but still they show themselves over and over again. It is reasonable to say that under some environmental conditions not currently present in most of the world, they were all useful ideas in that they helped a population survive under a set of conditions no longer present.

The myths and false beliefs of our time were the common wisdom of some earlier era, as some of our common wisdoms of today are destined to be deprecated to become the superstitions of the future. But this past body of cultural fragments are the shiny shards we put together to create new things that are useful and valuable. When we write or paint or create, we take bits and pieces from diverse sources and put them into a new relationship with each other, and say something never before said.

So while it’s important not to let fools and misguided mystics do actual harm to the world or damage its future, it’s also important to keep that junk pile of useless and false ideas, no matter how harmful they may once have been. Those who practice these ideas to the detriment of others are to be pitied and kept from decisionmaking posts, and (where possible) gently educated away from their fixations. But a combative stance toward them can do more harm than good by cementing their belief that they are being persecuted, and the group cohesion so produced can actually make the people holding these ideas more dangerous.

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