Recessive genes (2018)
I see that the page attributes the world's decline to inbreeding. Although that can certainly cause substantial problem due to the appearance of harmful recessive genes, those harmful recessive genes will die out fairly quickly. After a few centuries, the most harmful recessive genes present in Borlund's clone-parent population will have died out, and the less harmful (but still disadvantageous) genes will have declined in numbers. It strikes me as implausible that genetically disadvantaged people will be widespread four centuries after the world's revolution.
Is it canon that people will conspicuous genetic disadvantages remain widespread by the customary Traveller eras? If not, would it be reasonable to bring this world's history closer to genetic plausibility?
Consider the example of a clone family where the original has a particular gene that comes in the advantageous, dominant "G" form and the harmful, recessive "g" form. When "Gg" clones reproduce, their children will average one-fourth "gg" people (with the harmful recessive gene expressed), one-half "Gg" people (with the advantageous gene dominant, but carriers of the harmful recessive), and one-fourth "GG" people (with the harmful recessive absent).
The "gg" children are likely to have reduced reproductive success. Even if the harmful gene isn't a problem until after reproductive age is reached, "gg" people will be less able to support their descendants, reducing their reproductive success.
If genetic testing is available, "Gg" people will also have fewer offspring. Some will chose not to have children rather than risk passing on "g" genes, or seek abortions if pre-birth testing shows "gg" genes. Some people may avoid having children (or even relationships) with people carrying "g" genes, depressing the reproductive success of "Gg" people. (Genetic testing for over 500 genetic conditions is available in present-day society for a few hundred dollars.)
Of course, the founding population presumably would have had some harmful recessive genes. But even the most common harmful recessive genes are fairly rare. (Cystic fibrosis is one of the most common; about 4% of people of European ancestry are carriers. Similarly, sickle cell disease has about 4% carriers in West Africa, but only about 0.25% in African Americans.) The Borlund clones, based on just 30 elite founders, would probably have just a handful of harmful recessives in their gene pool — though they would be much more susceptible to novel diseases. Would the operators of the clone machines even leave known disadvantageous genes in place?
All of the information here (except for widespread genetic testing) was understood science long before the creators of Traveller were born; the science was published in the 1860s, and widespread by the early 20th century. It seems implausible to have a TL12 society put at risk by a problem known since TL5.
- The source of that section is Alvin Plummer's RICE Paper #AWP-00314. I'm not sure what Alvin's background in science or genetics. I do remember during the 1990s there were a number of articles about the dangers of the monocluture agriculture. And in a well trod SF trope, this takes a know or suspected problem and applies it to a human (or alien) population, and tries to explore the consequences.
- Genetics is never that simple. Take, for example, horse color genetics. Horse base color is either red or black (with black being dominant). There is a second gene, that if the horse is black, determines if the black is all over (a black horse) or just at the tips (Bay horse). There is a second, dominate, gene that determines if the horse is grey or not. Plus at least two other that hold further modifiers. And even horse breeders have trouble understanding how this works to be able to describe the color of their foals.
- So you have a world where the population is largely clones, with no expectation of sexual reproduction. I would not doubt the more obvious, and known, harmful recessives were eliminated. But the description implies these issues are third generation problem, and generally unanticipated. I would also say some of the problems are aggravated by chaotic situation. What would be a minor development issue under normal circumstances becomes much worse with a lack of food and medical care.
- - Tjoneslo (talk) 07:16, 22 June 2018 (EDT)
- A large nuclear weapon in the largest city wouldn't help either.
- A credit might be worth adding or clarifying, unless there's already clear credit there. — Steve98052 (talk) 13:37, 22 June 2018 (EDT)