Friday, September 30, 2016

Chromosomal Selection

The genetic grand transformation is one of the big changes or revolutions in how an alien civilization is set up and what it is like to live in the civilization. The headline item on that, here on Earth, is changes in human beings. Science fiction has been written about it, it has become popular in the on-line press, and every scientific advance is coupled with hundreds of opinions about what it all means.

It is not likely that genetic grand transformation on any alien planet will start with the aliens modifying themselves. There are too many other simpler things, which would bring benefit to the society, which would be done first. The sum of all these things might make the eventual improvement of the aliens’ own gene pool easier to be accepted.

On any alien world, they would have been doing genetic modification, in an inefficient way, since the hunting grand transformation or at least the agricultural grand transformation, which are the first two of these transformations that shock the civilization into a new phase. Husbandry of animals, to make obtaining animal food much easier, started in one of these two, and to become a keeper of formerly wild animals, some selection has to be made. Animals of a particular species may vary in their acceptance of being corralled or penned, or in the case of tamed animals, their willingness to give up their former style of lives for a more certain food supply. The selection of adaptable animals is an act of genetic modification. There may be some non-genetic, experience factor in their adaptability, but there is also a genetic component.

Sowing seeds doesn’t necessarily involve any alien modification of natural genetic codes, but the next step of agriculture, where seeds are selected from desirable plants and then sown, as for a tree rather than something like a grain, does. Any act of selection of either the animal or plant on the basis of some desirable characteristic is an act of genetic manipulation, albeit rather clumsy.

This process of selecting improved or altered characteristics in animal and plant species simply goes on and on, becoming more organized, as the alien civilization progresses through its development. Selection becomes augmented by the creation of the variations over which the selection can be made. Two animals, each one with some desired characteristics and some less desired characteristics, can be mated, and the offspring sorted out to find one or more with more of the total set of desired characteristics than either one of the parent. Two plants can be cross-pollinated to attempt to accomplish the same goal: the collection together of multiple desirable characteristics. This is a slow and painstaking process. If the animals have a multi-year growth period before the characteristics can be reliably noted, then the cycle time for improvements is paced by this and must be slow. The same holds for those plants with an annual or longer growth cycle.

Because of the uncertainty of the mixing of the genetic codes from two individuals of the same species, there might be many generations of the species before the desired improvements are obtained. And even then, the process may be inefficient in another way as well, the improved animal or plant might not breed true, and the characteristics are not reliably transmitted to subsequent generations. For some plants, particularly trees, this problem can be solved by grafting from the successful product onto rootstock of some hardy species or variety, and then as long as propagation goes by grafting, the characteristics can be maintained. Reverting to propagation by seed would undermine this methodology, however.

Another drastic inefficiency in manual cross-breeding is that the desired genes may not be included with the offspring or with multiple offspring. Sexual mixing is a lottery, and sometimes the chromosome that has the gene that controls the desired characteristic is selected and sometimes not. With plant breeding, it is often fairly easy to grow hundreds of copies of one pairing, and then hope that at least one of them carries the desired characteristics. However, with plants that take years to get to production, the time needed to maintain all these possible copies is large and the investment large.

Perhaps one of the first steps in the genetic grand transformation on planets which have largely finished their industrial grand transformation would be to make the breeding of plants and animals more efficient. One step, even before the genetic map of a species was known and translated into characteristics, would be to make the combination process more efficient. A species with, say, eight pairs of chromosomes, would have two to the sixteenth possible combinations from two chosen parents. This is about 65 thousand combinations, which is much too large for any reasonable field trials. However, it is not necessary. Simply splitting the pairs in each parent and combining them into four descendants allows for the selection of two traits, assuming they are not recessive. Then the same process can be used again and again. To save time, four groups of chromosomes could be used.

Thus, simple separation of chromosomes and their return to a state that allows a growing plant to be started would provide a quick step up in the speed of, and rate of return on genetic selection. Any alien civilization which had passed through the later stages of its industrial revolution, which includes automation of processes, would be able to produce machinery to automate this process.

Thus, the development of improved varieties seems to be likely to be the first major, civilization-wide, step in the genetic grand transformation. At this point in the common path forward of technology, and therefore of any alien civilization, as per technological determinism, the alien civilization will still be growing their own foodstuffs in ways still recognizable as related to evolved growth. Once chromosomal selection is common, the way is paved for two other advances: the interpretation of specific genes, which allows chromosomal selection to be made even more efficient, and the alteration of chromosomes to modify individual genes. This latter step is the one that is most tricky, but the former one, if done earlier than the latter one, will facilitate it and make it much quicker to bring to success. Gene interpretation is something that will fall into place reasonably quickly, if the alien world is like Earth in that there is great genetic similarity between different organisms.

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