Select only smart people for a colony. Do their descendants remain smart?

Another crazy idea that occurred as I was watching the closing ceremonies of the Olympics this evening.

I was looking at all those young healthy faces, and had in the back of my mind the news reports of the Olympic Village being a total makeout pit, thus ensuring the next generation of athletes.

What would happen if we took a few hundred thousand people from the top 1% of humanity and isolated them to start a new colony?

Let’s say, Mensa members, Olympic athletes, rich people who have earned it themselves, social geniuses… all people who drew genetic winning cards and either grew up in environments where they flourished or had the strength to overcome their non-flourishing environments.

They interbreed with each other and the generations pass. Would the total population remain smarter, stronger, etc than the average of the people they left behind?

Probably not.

We don’t really know what goes into making someone best in the world either physically or mentally in some endeavor, but it isn’t just genetics and it isn’t just environment. Also, some traits may be a result of having different combinations of genes rather than just one or two special genes.

So mating amongst champions of [insert something here] won’t result in a continuing line of super humans. Some of the kids will be athletic or brilliant mentally but others will get a different assortment of inherited traits. Different body types excel in different sports, as an example. Gymnastics favors the short and lean, power lifting favors the heavy set, basketball favors the tall, and so forth. So, a gymnastic marrying a shot-put champion may result in children of some intermediate body type less specialized for a particular sport.

Ditto for mentally brilliant people - smart people are not guaranteed to have smart kids, and it may be that very smart people getting married are at greater risk of producing kids on the autistic spectrum.

That’s just the genetics - there is also the environment, and beyond that, not everyone wants to achieve in the same manner of those exceptional folks as doing so is incredibly hard work.

So no, starting with smart/athletic founders of a colony does not guarantee continued excellence or a higher than average intelligence or physical ability over time.

Since geniunely smart and creative people usually have mental health issues, I’d say their product may end up being very smart, but also completely mad. Yes, that is an exaggeration, but the overall issue is not.

I always heard that as far as intelligence goes, there is a tendency to regress to the mean. Smart people will generally have smart kids, but two genuises don’t always beget genius progeny. I believe the reverse is true also, but then again, parents who don’t care about education will put their kids at a disadvantage.

On the other hand, beautiful people have beautiful kids, and world class athletes quite often have very athletic kids, but there is also a bit of nuture involved there. Living in California, I’m convinced that a lot of good looking people tend to move to the coasts. I’m biased though, and was born here and not particularly good looking.

Wouldn’t inbreeding be a problem?

In a population of 100 000?

My assumption would be that, for any given specific genetic trait (intelligence, height, etc.), the bell curve for the new population would remain pretty stable over time, assuming the environment doesn’t change.

To illustrate, if you took 1000 people with 180 IQs and created a new population, I am guessing that their great-great-great -great grandkids, assuming that environment has been stable, would average around 180 IQ.

This many not be true, though. I have no idea.

As far as beautiful people at the coasts, no, I don’t think so. I think people in the Midwest are less likely to do things that will help their appearance like makeup, expensive hairdos, flattering designer clothing, plastic surgery, botox, exercising to stay fit, etc., etc. I do notice that Midwesterners, on average, don’t tend to be as attractive as Southerners, West Coasters, etc.

I doubt that’s genetic, though. Why would it be? Why would naturally attractive people move to the coasts?

I can see attractive people moving to Hollywood to get into the movie business, or to New York for theater/Broadway, but those are very specific places, and don’t represent the whole coasts.

I also notice that Southern women tend to do a great deal more work on tanning, hair, makeup, and clothes. I think this explains a lot of the difference.

My guess is that the descendents would be somewhat smarter than average; the tendency to regress to the mean would be somewhat negated by their genetic isolation, as well as the founder effect. They’d have a greater concentration on average of the genetic variations that can result in higher intelligence, fewer of those that lead to lower intelligence, and no interbreeding from outside to change that. They’d still regress to the mean, but it would probably be a new mean. As their population grew, they’d still have that greater concentration of “smart genes”, because that’s what they started with (founder effect).

I would imagine that dogs would give us the best examples of what we can expect from selective breeding. Race horses, and many other domestic species are also good examples.
My hobby was training bird dogs for competition trials. Often physical traits would tip me off to desirable hunting instincts I would be looking for in a trial dog. Same with undesirable traits could often be detected by a seemingly unrelated physical trait.

Some genes can code for several things simultaneously. Sometimes those things are completely unrelated. I believe there’s a gene that codes for both red hair and extreme obesity. Not everyone who has red hair has this gene, but the ones that do are generally obese.

Also, certain nutritional deficiencies in the womb can cause certain epigenetic skeletal malformations, and other types as well. I would bet that those same nutritional deficiences can cause other problems as well. I would guess that this might also be related to your observations.

Cite?

It can’t be hard to find the truth on this. I’d google it, but I keep expecting some doctor of genetics to come into the thread and wow us with his/her knowledge.

Yeah, I’m googling. As far as I can tell, heritability of intelligence seems to be very high, around 80%, so one would assume that there would be relatively little regression to the mean for this particular trait.

Other traits that are less inheritable probably would see more regression.

I’m not a doctor of genetics, but my undergrad was in genetics…

Der Trihs is spot on right.

The new mean would likely be different than the old mean. More so for traits of high heritability. But there would still be a bell curve distribution for the population as a whole. Intelligence and height seem to be traits of high heritability.

Some would be below not only the new mean, but also below the old mean. Establishing a population using a cherry picked group of people with an IQ of 180 would likely result in a population with a mean IQ* of something higher than 100 but probably not as high as 180.

  • as measured against the old benchmark. This ignores the reality that the mean IQ is defined as 100, and arguably the 100 of the new population would mean something different than the 100 of the old population.

Heritability of intelligence has been subject to study and it appears to be more genetic than environmental. Estimates range from heritabilityof 0.5 up to about 0.8 with somewhere around 0.75 commonly cited.

Intelligence is shaped by familial environment in the early years of life as much as any other single factor. If the child is provided a rich and stimulating environment (particularly in the first five years of life), then that will maximize the child’s intellectual growth within what constraints or limitations are imposed by his genetics. So even if the traits that make up intelligence are 100% not heritable, an intelligent population of parents will provide the optimal environment to maximize their children’s intelligence.

I have one unscientific support for this idea: I have visited Los Alamos, New Mexico several times. The population consists largely of the descendants of Manhattan Project scientists–supposedly then and now, the highest proportion of PhDs in any American town or city. Those people are very, very, smart, taken as a group. You can tell by talking to any random person or group of people. I played bridge in the local club, for example, and everyone played at expert level.

Instead of 100,00 humans in one isolated colony, 200 completely isolated colonies of 500 people over thousands of years would produce many new branches on the evolutionary tree, some of them superior to today’s man. The way it is today, any advantageous genetic mutation is lost before it can be spread to the general population.

One problem with breeding for a selected trait is that you have to be willing to refuse breeding privileges to carriers of undesirable traits. Now, when you’re breeding animals, you don’t have to worry too much. If Fluffy or Fido has an undesirable inheritable trait, then you just desex the animal and consider it a pet, or you kill it. If you’re trying to breed humans, well, it becomes a bit more problematic. I’ve found that some of the people who are least suited for parenthood (both genetically and skillwise) are the ones who are most interested in having kids, and lots of them.

This is an extremely silly marker of intelligence.

And, the mine gap.

a man after the OP’s heart.

**bolding **is mine

Actually, no, if the studies are to be believed genetics is MUCH more important than environment when it comes to intelligence. That is what a heritability factor above 0.5 means.

In the other aspects, I quite agree with your comment.

It is not to say that environment is unimportant. If an environment was suitably manipulated (lack of adequate nutrition, presence of physical/sexual/psychological abuse, e.g.) it might be impossible for a child to develop his/her full potential.

And indeed, perhaps more intelligent parents might be more capable of recognizing that environmental conditions do have an impact and thus be better able to provide a positive environment for their child to be able to reach his/her potential.

So yes those traits that get measured as intelligence are highly inheritable - the question remains open however if a higher load of those genes results in more intelligence or becomes deleterious at some level resulting in brain dysfunctions or disease susceptibilities.

One hypothesis for autism is based on that thought process: the genes that lead to superiority in various analytic sorts of skills (including those that underlie math ability) when present in larger amounts from both parents result in a higher incidence of autism.