Discussion Main / SuperBreedingProgram

There is no technical flaw with the basic idea of eugenics; you can breed humans like you can any other animal. Some of the inventors of quantitative and population genetics, e.g., Fisher, were very supportive of eugenics. The question as to whether it was properly implemented is a different one.

As for the claim concerning northern-European pigmentation: there isn’t any irony.

Recessive alleles aren’t inherently bad. Selection against rare recessives is inefficient so deleterious recessives can persist in a population at low frequencies. Baring certain particular cases, if a recessive allele persists at high frequencies it isn’t deleterious.

Migration into a population does reduce the effects of local selection so the claim that paler pigmentation could not have persisted through large quantities of geneflow is correct (unless the selection coefficient was very high). The effects of migration are a concern in conservation genetics for precisely this reason. Migration into a given population can cause the population to diverge from the local optimum and subsequently suffer from a reduction in fitness.

Since recessive alleles are expressed less frequently than dominant alleles (this effect diminishes as the frequency of an allele approaches 1; if an allele has a frequency of 1, it will always be expressed, recessive or not) the effect of migration would be more noticeable. Since recessive alleles are less frequently expressed selection is correspondingly inefficient and lower levels of migration could negate selection. Dominant alleles are not however immune from the effects of migration.

Very low levels of geneflow are sufficient to introduce any adaptive variant another population might have. Higher levels of migration would (insofar as the migrants have a higher frequency of the variant in question) cause the frequencies to converge more rapidly but aren’t necessary to introduce adaptive variants.

Selection and migration are not the only forces that can result in changes of gene frequency. There is also mutation (which can in this case be ignored since it is rare) and drift (which can also be ignored for reasons that will now be explained). Drift refers to the effects of random sampling and can result in changes of gene frequency without selection, or even despite selection. Drift is inversely proportional to the size of a population. In very small populations drift is important but its importance decreases precipitously as the population grows. An easy way to see this is to look at an analogy. If you flip 2 coins, it isn’t that unusual to have a result of 100% heads, or 100% tales. If you flip 200 coins, the result is going to be very close to 50% heads and 50% tails. In the same way, if you have two individuals, one of which has a single copy of some variant, and they produce 2 children, it’s very possible that none of the children have a copy. If you have 100 such couples that each produce 2 children, the frequency is going to be about the same next generation. Northern Europe has historically had a comparatively small effective population size, but it doesn’t take much to make the effects of drift very small (see above) and in particular, it would be near impossible for a deleterious allele to reach a very high frequency in all but the smallest populations.

Summary: It is perfectly possible for a recessive allele to be superior (in whatever context, a breeding program for example, or fitness in a given environment). A population being relatively isolated isn’t an inherently bad thing. Pigmentation in northern Europe is probably the result of selection.

I can provide formulas and citations if necessary.

At the moment, I have only removed references to hair and eye pigmentation, however the whole example is inaccurate and needs to be replaced.

What if the character manages "undesirables" by marrying them to an "inferior" race?