I know we know how to breed crops that are specifically adept for their environment, we also know how to breed animals for the purpose of serving mankind’s ambitions.
Are was at a stage where we understand ‘how’ to breed a specific type of human (personality wise)? IE, aggressive, passive, loyal, disobedient, smart, stupid, etc? Could a dictator in foreign country X selectively breed more passive, more loyal and more intelligent subjects via things like forced impregnation, forced abortions and forced sterilization or is breeding humans more complex than breeding dogs and breeding corn?
If this is feasable I wonder which dictator will be the first to try it.
We don’t really understand exactly how to breed for particular behavioral qualities in in animals, at least in the same way that they can be selected for coat color or other physical attributes. And we understand even less about the genetic basis of behavior in humans.
Even if we did, it would be impractical because of the very long generation time of humans. Few dictators have lasted long enough to see even three human generations come to adulthood, and that’s not remotely long enough to establish a population that would breed true for such a character.
While certain breeds of animals have been bred for certain behavioral characteristics, such as aggressiveness, docility, etc, this has been accomplished over many many generations. But human generations are five to ten times longer than those of domestic animals, so any such modification would likely be the work of centuries.
While I recognize your expertise, do we not know that certain disorders (psychopathologic and otherwise) have strong genetic components, suggesting that both selective breeding (or non breeding) with said invividuals whould, on a sustained and systematic level, yield some very long-term effect? I thought recent findings suggested a strong genetic component to disorders ranging from chronic depression to highly aggressive behavior. While the genetics of such a proposal certainly aren’t understood, might not selecting out these behaviors/disoders, as outlined, have at least some very LT effect?
Question two, isn’t this the basis for the so-called Nobel sperm pool and in vitro fertilization? Obviously, female recipients aren’t subject to such strenuous screening criteria, but what compelling evidence is there to suggest that the mating of two highly intelligent individuals will, more often than not, yield children with higher than average IQs, accepting IQ as a benchmark for intelligence, if you will.
Any informed answers/discussion on this would be appreciated.
I’ve been meaning to post a similar question myself for some time, but was wondering how to couch the language. I suspect that breeding for personality traits would be impossible since we don’t fully understand how all of ovur life experience affects those things – and we’ve got nearly 20 years of formative experiences.
But could the impossibly long-lived dictator create breeds of humans who were 2 feet tall (human chihuahuas) and ones who were 10 feet tall (human great danes) or always red headed (Irish…oh wait a minute!)?
Yes, there are some behaviors that appear to have a significant genetic component. However, we do not really understand the genetic basis for them, and they are all almost certainly multifactorial – they are governed not by a single gene, but by many. Therefore they will be rather difficult to select for – much more so than for characters governed by only one or a few genes. While you might eventually see some result by breeding hyper-aggressive individuals with each other, it’s going to take a long time for a definitive result.
Although there is certainly some genetic component to intelligence, it’s degree of heritability is controversial, and estimates vary greatly between studies. A couple of sites I checked suggested that a consensus figure for the heritability of intelligence (the percentage of variation due to genetics) is about 50%. This is much lower than the heritability for even such multifactorial character as height, which has a heritability of about 90% (at least in the U.S.). Selection for intelligence might be possible, but again it’s going to be much harder and take longer than selection for a character like height.
I’m not saying that such selection would be impossible, just that it would likely take centuries of rigorous effort, not the few decades a dictator might have available.
There’s also the question of whether our domesticated animals and crops have been bred for breedability. It’s well possible that they have the genetic background for mallibility built up over thousands of years, and humans don’t.
The shortest dwarfs are roughly two feet tall, and since the genetic basis is known it would be feasible to select for the character. Inbreeding could fix the character pretty well within a few generations.
It would probably be feasible to breed a race of seven-foot tall people pretty readily. However, as Shalmanese indicates, much above that height some serious physiological limitations would set in and make selection much more difficult.
A related question is, are some populations really different in personality? Are Germans really industrious, Japanese really thrifty, etc.? If there are real differences, that cannot be explained by cultural influences (and I have no idea how to determine that), then that would imply that these traits can be bred, wouldn’t it?
Quite possible. Human giants tend to be rather short-lived, as do giant breeds of dogs like Great Danes and Wolfhounds. This is probably due to the physiological stresses that have been mentioned.
The interesting thing is that although humans have known how to selectively breed animals for thousands of years there has never been a recorded instance of successful selective breeding of humans, even of slaves. I imagine the real problem is that humans are much harder to control than animals, and the desire to continue a proposed breeding program would have to last many generations. One power-mad dictator can institute a breeding program, but will his successors continue it? Even if they had the power to impose such a breeding program would they have the same goals?
As for breeding out genetic defects or genetically controlled personality traits, it isn’t that simple. Let’s imagine a simple mendelian recessive trait that you are trying to eliminate from the population. Sure, you can euthanize or sterilize all people who express the trait phenotypically. But that doesn’t mean very much, especially if the trait is very rare. The rarer the trait is, the less selective pressure there is from eliminating those homozygous for the trait. If 1% of the population is a carrier, then only .01 * .01 will exhibit the trait. Eliminating that person will only lower the frequency of the trait from 0.01 to 0.0099. Not much selective pressure. If eliminating genetic disease through controlled breeding were simple then why do domestic dogs still express terrible genetic diseases today?
And if the trait is common, then you’d have to eliminate the vast majority of the breeding population. I suppose this could work if you are only trying to create a small population of a particular human breed, and will keep the vast majority of the wild type humans to support them. But who is going to do the work of raising large numbers of the new breed of people? Think about how much work it takes to raise just one person to adulthood. Right now dictators get those people for free, since their parents donate the labor. But think of the trouble trying to force your peasants to foster-parent the new breed of humans. That’s a lot of work.
No, there aren’t any. I don’t know how to answer your question any differently. There is no scientific data indicating that anything other than cultural influences are in play.