Human genes and evolution

Great Debates
1

The main subject here is genetical manipulation of humans, sorry for the length of my post but I felt I had to bring up several sub-issues here, hopefully they will help spark debate.

English isn’t my first language so I’m worried that I will inadvertedly offend people with the way I use words. I would like to explain from the start that I don’t put a “value” into it when I use words that (I think) can be interpreted that way, such as disease. I try to refer to them as hereditary attributes but I am frankly not good enough at this to be PC and correct, but still wish to debate this. Apologies in advance if I come off in a hurtful or offensive manner, this is not my intention.

First a premise which I hope everyone can agree with. Homo sapien sapien evolved through the process of natural selection. In the last steps of it is seems as though cunning and guile became more important then pure physical attributes such as speed and strength. In creating the human civilisation, the proccess of natural selection has more or less been destroyed. In many countries now, people that would have died out before they could ever procreate earlier, don’t anymore.

This means that those attributes that are genetical, such as allergies and certain diseases, will be carried on into future generations. Considering that these can pop up naturally, but won’t spontaneously go away, they will continue to become more and more common. Someone with a hereditary disease will get offspring together with someone with hereditary allergies, and the offspring will have both, and might in turn chose a partner with other such attributes. If we extrapolate we will end up with a population that is riddled with such things, basically a society where everyone will have all sorts of allergies and diseases from birth.

This wasn’t a problem 50000 years ago, because someone born with a serious allergy or other handicap would simply die before they could pass it on. I personally don’t like people dying, so I’m happy that has changed, but it does pose a problem. Basically (and try to NOT imagine me with a German accent and in an SS uniform when saying this) the “quality” of the human “gene pool” is deteriorating.

If you agree that this is a problem, and (like me), think that people dying is a very bad thing, there are only (I think) two things we can consider at the moment. One is to simply ignore it and deal with the effects, the other is to use the knowledge of the human DNA to actively replace the proccess of natural selection. This should be quite possible in the near future.

So, I suggest that (as soon as it is possible) we use science to remove genetical attributes such as allergies and hereditary diseases from zygots.*

Now, if we can do that, there is another logical step. If we can remove what is “bad”, can’t we also tweak what is “good”? Would it be wrong to (if it is possible) figuratively just turn up all the positive dials on the DNA switchboard? Max out the positive attributes so to speak, so that babies would be born with the genetic setup to have perfect immune systems etc, and the maximum physical potential for strengths, intelligence and all other attributes. Pretty much, an “übermensch”.

When discussing this, in my experience, people are always against it and always because of the same two arguments, which are (simplified):

  1. They believe that these genetically enhanced people will turn the world into a fascist state and everyone will be opressed
  2. People will want all their babies to be blonde and have blue eyes.

To start with argument #2, I have a few objections. First, and least important, why would everyone want babies who are blonde and have blue eyes? Just because that was the nazi ideal? Personally my preferences are black hair and green our brown eyes. Also, do you really think that people are that “shallow”? I know that if presented with the option by a doctor for my future child I would just go “I don’t care, let him/her have whatever hair and eye color they have”. More importantly though, I feel this argument is like banning all surgery because people will use it to enlarge their breats or “fix” their noses.

The #1 argument is a bit weird to me. I tend to ask “Wouldn’t it be great if everyone was just smarter?” and for some reason everyone (I swear!) reacts with “Then they would take over the world and… <insert the third reich>”. Why would they do that? First of all this would be a transitional period, after a couple of generations everyone would be born with “perfect potential”, second, since when do intelligent people equal “evil”? I would say that physical capacity for “intelligence” (what I mean is really just efficiency of the brain but… well I hope you try to understand me) doesn’t automatically pre-dispose people to neither good or bad, but actually, I wonder if not the opposite is true. The most “evil” men in history weren’t as far as I know exceptionally intelligent. The extremely intelligent ones on the other hand tend to (just my impression) be very “good”. The biggest genius of our time, Einstein, was a pacifist and held three things higher then all others: kindness, beauty and truth. Another person famous for his intellect was Goethe, who’s idea of the highest in human life was seeing people work together towards a common good. I’m not saying smart = good, but at least the opposite is not true.

So, why shouldn’t humans, in the future, try to enchance themself with the means we (will) have? As far as I can see the alternative is to continue with the “patch-work” of common medicine in a never-ending spiral.

  • Well somewhere in the proccess between conception and birth anyway
2

The problem with your concept is that there is no absolute as to what is “good” or “bad”. It might seem obvious that certain allergies and hereditary diseases are inherently “bad” and could be removed from the gene pool without anyone missing them.

But what happens when you give some government the right to control such things in the population? Who will be at the helm of such an organization, and what will suddenly be declared to be so “bad” that the government must step into the womb and dismantle it. The potential negative ramifications far outweigh the potential benefits. There is constant debate among those who would shape society from above about whether, at heart, people are angels or swine. Those who believe in angels are often bitten by the pigs.

As for diseases, the situation is far from cut and dried.The prime example is sickle-cell anemia. How could such a crippling genetic disease have survived this long, wondered the scientific community? Turns out those with the gene variant that brings on sickle-cell anemia are inherently resistant to malaria. So which variant of the gene is “bad” and which is “good”?

Evolution has never stopped working. We are not the only animals who have evolved to shape the environment around us. Who is to say that the cunning involved in hiding from potential mates your myopia or inherently crooked nose does not convey some benefit on offspring?

The world is far too complex a place to think that we know enough to declare what parts of nature are bad or good. That is why a program of eugenics is never a good idea.

3

I realized I only addressed the first half of your OP, but the good/bad dichotomy extends to the rest, I think.

“Wouldn’t it be better if everyone was just smarter?” If that were unequivocally true, we would have evolved in such a way that those less intelligent* would not be attractive to potential mates, and would not be able to breed. Not that I don’t ask that very question on my commute home every day. :wink:

*and what exactly does that mean, by the way? There is far from universal agreement as to how intelligence can be quantified and measured.

4

*Originally posted by * Stoneburg :
This wasn’t a problem 50000 years ago, because someone born with a serious allergy or other handicap would simply die before they could pass it on.
I just wanted to point out, along the same lines as what scotandrsn pointed out in his previous post about sickle cell anemia, that it’s difficult to say what genes are good or bad. Atopic peolple in our highly sterile environ would probably not develop allergies if exposed to parasites early on. On the other hand, people who did not(or do not in some third world populations) mount a response to parisites(particularly helminths) would most likely exhibit higher morbitity, than responders. For most of human history, we’ve lived with internal parasites, now in developed countries we don’t, allergies are pretty much a recent phenomenon that would’nt have effected human evolution.

5

It is inevitable that humans will eventually do exactly what the OP is suggesting, assuming we don’t destroy ourselves first. The preliminary steps are already being taken with genetic screening of embryos. However, it’s important to realize that the science is very much in its infancy. We know a bit about genes, but not much about the way they produce protiens, and it’s the latter that get the job done. We don’t really know much about how genes interact either. It appears to be a rare gene indeed that, by itself, controls only one thing. The popular idea that we can catalog genes and then start tinkering is woefully short of the truth. Bottom line, this is an incredibly complex scientific and engineering problem that we’re only beginning to understand.

6

More than that, evolution works in a far more subtle way than we could ever imagine doing. There are over 30,000 genes in the human genome. With gene therapy or zygotic selection, one can imagine modifying or selecting for a handful at best. Natural selection, however, works based on the entire fitness of an animal, which depends not only on the genes, but on epigenetic and environmental factors as well. As labmonkey pointed out, this is demonstrated by people with atopic histories – environmental exposures actually would have increased their fitness substantially, so what we perceive as a huge hit in fitness in the modern world probably wouldn’t have been all that bad in a “dirtier” environment.

There are certainly reasons to do zygotic selection or gene therapy – there are devastating monogenic diseases which we can avoid now. Take cystic fibrosis. 1/25 Caucasians carry a cystic fibrosis gene, this means that in a random Caucasian breeding, 1/625 breedings will give 1/4 progeny with cystic fibrosis. Or approximately 1/2500 will be born affected. Recent studies have failed to demonstrate positive advantages for the CF allele (it was hypothesized that heterozygotes have some resistance to TB, but they have been unable to show that).

The thing is that selecting against or fixing CF (or SCA or Tay Sachs) zygotes means that you are not affecting the prevalence of the allele in the gene pool. What you concern yourself with is the 1/2500 occurence there, and ignore the 1/25 carrier state.

I can see the temptation that would exist if we found one allele that boosted intelligence and we had a relatively trivial way to select or change to that allele. But intelligence is a complicated trait. There are genome factors – there are probably thousands of other loci that affect intelligence, not to mention penetrance of the engineered allele. This is only part of it – much of intelligence is based on environment. Lastly, the truly stunningly intelligent are, for the most part, not a happy bunch, and I can’t imagine it would be a very popular option for parents if it turned out that way. Look at the life stories of people like Newton, Leibniz, Ramanujan, John Nash, William Sidis, etc. So in the end, it is very hard to say if it will be more popular than the old-fashioned way.

7

Stoneburg,

The real problem here is that traits like intelligence, beauty, and strength do not follow the traditional Mendelian genetics of dominance and recession. With eyes and hair most of that is reasonably simple, blue eyes recessive, brown eyes dominant.

But as John Mace pointed out, intelligence, beauty, and strength have more to do with nurture than nature. Have you ever noticed how attractive parents can have ugly children? Or smart children have stupid parents?

With all that said, I’d like to point out that it is now possible to pick the sex of the baby by pre-screening the sperm. This has been around for a few years at least and has yet to become wide spread.

My guess is that this type of technology, when available, will be expensive. So rich people will be able to have strong, smart, attractive offspring, which is pretty much what they get now (Paris Hilton not withstanding…)

8

I’m in favor of whatever is reasonably and responsibly necessary to erase devastating genetic abnormalities from man. When it comes to tweaking in order to improve overall intelligence, I see what seems like a large problem with that. Who is then going to work at the car wash and who is going to ask if we would “like fries” with our order? I’m actually not kidding here. Different levels of intelligence allow us to fill all of the necessary roles our society requires. Wouldn’t more intelligence for all create more misery or discontent for some?

9

First of all, as others have alluded to, the problem of allergies and diseases is more complicated than first glance would suggest.

Allergies, for instance, only appear in societies with what we call “modern” sanitation. There is some evidence to suggest that, in a pre-20th Century level of sanitation (or lack of it) some people have a greater than average resistance to intestinal parasites. These same people, this evidence suggests, in an environment with modern sanitation, develop allergies. So, in a dirty, filthy, parasite-ridden environment they are actually MORE fit than the non-allergic. It is the environment that changed, not their genes.

Likewise, the usefulness of being a carrier of sickle-cell disease is well documented. In a country like, say, Nigeria, being a carrier of this trait is a definite survival advantage, and will continue to be so as long as malaria is a common disease in that area. It would be very unwise to eliminate this “harmful” trait in Nigerians because the deathrate from malaria would then increase.

Being a Tay-Sachs carrier MIGHT be protective against turberculosis. Being a cystic fibrosis carrier MIGHT be protective against diarrhea disease - which are still major killers in many parts of the world. These genes, like that for sickle cell, are beneficial in half doses, meaning if you eliminate them you may leave entire groups of people less fit. Far better, at least in some cases (like sickle cell) would be to work on means of alleviating the suffering that comes with a double-dose of these genes.

Likewise, allergies are caused by an overreactive immune system. Again, there is some evidence that, while allergics are more prone to auto-immune diseases, they are less likely to have cancer, or to die from the cancers they do get. So… which is worse, allergies or cancer? But since some people with allergies still get cancer, and plenty of folks without allergies avoid cancer, this indicates a very complex situation.

Also consider that, unlike other animals, people are thinking beings. I personally have known several people who, due to gene-based illnesses in their families, have voluntarially chosen not to reproduce. Some have gone childless, others have adopted. And this is not an entirely new phenomena - there are historical accounts of people choosing not to marry and reproduce for a variety of reasons, some having to do with fear of inherited disease.

Are you sure?

First of all, not all genetic diseases are passed on by those who suffer from them. Hemophillia, for instance, is passed through the females in a family although it is almost exclusively the males who suffer the disease. There are other, sex-linked diseases with similar inheritance. So some of these disease could easily spread and become more common even if everyone with the disease itself died too young to reproduce.

Also, there are historical accounts of people with severe handicaps growing to adulthood, making a living, and even having children. Having a genetic disease or condition, even in a very harsh environment, does not guarantee one’s early elmination from the game of life. Usually, such individuals are unusually blessed with talent or advantage in some other way, yes, but if a trait is so beneficial it can compensate for severe disability it may be a trait we want to keep!

This also touches upon the fact that no one is genetically perfect - we all carry “defective” genes, genes that would be severely damaging or even deadly if our offspring got a double-dose (which is why incest is bad), and we all carry genes that are “good” or even 'better than average" in other areas.

Hmmm… as I pointed out, even something as annoying as allergies might be beneficial in some environments. I don’t think folks living near and drinking out of parasite-filled rivers should have their “allergy genes” eliminated if those genes can provide some protection against those same parasites. People in malaria-prone areas should not have sickle-cell or thallasemia scrubbed from their genes entirely until malaria no longer exists.

SOME hereditary disease, where there is NO advantage to being a carrier, you might make this argument for. Even if Tay-Sachs protects against death from TB, we have enough other treatments for TB and perhaps we can argue that that particular gene has outlived its usefulness to humanity. But we must be very careful about doing these things.

Or, if we could go into a zygote and fix trisomy 21… now THAT would be hard to argue against. Currently, the only choice is a child with Down’s Syndrome or an abortion - a very crude choice at best, and to many, for whom abortion is unacceptable, no choice at all.

What if a double-dose of a “good” gene is actually bad for you? What if you only benefit if you get just one of the “ubergene” and need a normal gene to complement it?

For example - there has been a sharp rise in autism in the so-called Silicon Valley area. These children are frequently born to very intelligent people. Could it be that autism arises, in some cases, from too much of a good thing? In which case being a carrier of an “ubergene” is the ideal state, just as being a carrier of sickle cell is the beneficial state, and having two copies actually causes a problem.

Einstein also showed symptoms of what is now called “Asperger’s Syndrome” and had a great deal of trouble relating to others in his family or socially. He may have been very intelligent in some areas, but he was no “ubermensch”

There is also the question of what is intelligence? Someone who excels at math and science, like Einstein? But we also need people who are good at languages and diplomacy - and someone who is extraordinary at those skills may have very poor talents in math and science. Are they smart or not? Or smart in a different way? The modern world needs a multiplicity of talents, skills, and traits and it may not be possible to combine them into identical, perfect people.

I vote for a very cautious advancement in these areas. Sure, there will be some people who available themselves of these techniques to attempt to make the “perfect” baby for themselves - and there will surely be disasters among the first successes. We are learning a lot, but I don’t think we’ve learned enough to make truly wise and informed choices yet.

10

For the sake of debate I simplified it, I could spend pages describing everything in detail (well… as far as my limited knowledge would let me) but that would make the OP unacceptably long so I was hoping that people could use some benevolent extrapolating. We can have a 10 pages long debate on what constitutes “intelligence” (and I wouldn’t mind), but that would be just that, another** debate so I am hoping people can just try to understand the basic question instead.

Having said that, studies on identical twins seperated at birth show that 70-80% of a persons mental capacity is indeed genetical (which still leaves a big chunk for nature and nurture of course:)).

I actually finished reading about Einsten a month or so ago and he was indeed suffering from “emotional detatchment”. I wasn’t claiming that he was an “übermensch”, I was using him as an example that people that are extremely intelligent don’t tend to be “evil”.

I’m sure that if everyone was a genius we could find a way to overcome this obstacle. Maybe someone could invent, I don’t know, some kind of machine that would say “like fries?”. :stuck_out_tongue:
I conceede that there is a practical problem of seperating “good” genes from “bad” ones, and another problem deciding which is which, but that dodges the issue. If we could, should we?

11

Interesting point, I agree with emacknight though that economics will play its part - genetic alterations will only be available to the rich.

Theres also the competition between genetics and the medicine industry. I can’t honestly see genetics generating more revenue than traditional medicines to begin with so it would be the governments preference to favour the medicine industry.

Maybe in the distant future when it all works, there is a good market and the price is low we will have to worry about eugenics, but not for a loong time IMHO.

12

Why would it be a good thing for everyone to be more intelligent?
The problems of this world are NOT caused by a lack of “intelligence”.

Also

"First of all this would be a transitional period, after a couple of generations everyone would be born with “perfect potential”, "

  • Your faith in human nature is touching.

"second, since when do intelligent people equal “evil”? "

We arent talking about intelligent individuals: we are talking about a genetically enhanced caste who are superior and know they are superior.
But my main objection to genetically improving the human race is:

what’s in it for me?

13

No… we are talking about individuals that are born with better conditions with regards to becoming intelligent. Intelligent enough (I would hope) to realise that they aren’t superior, in the same way that someone born wealthy and white isn’t superior to someone who is born poor and black, they just have better conditions.

Your comment about “faith in human nature” fails to make sense to me in its context. Everything has a transitional phase from when it is introduced until it has become common.

What’s in it for you? Not much, but there’s a lot in it for your children and your childrens children.

And yes, there is obviously an extremely strong economical interest against this, since the pharmaceutical industry makes a considerable profit of peoples illnesses and this could remove many of them. That doesn’t mean I support the argument that it is good that people are sick, because companies makes money off it.