|MadSci Network: Genetics|
Hi Nezos, I think your question is the “dream” of million people!:-) Intelligence has been of interest of both developmental neurobiologists and psychologists for many decades. One important aspect of studying intelligence is that it is often very difficult to evaluate the “intelligence” of people subjects. Obviously a practical solution to this is to device some sort of tests and then to make some score about intelligence. Hence the invention of the Stanford-Binet test, Wechsler test, Raven’s Matrices, etc. and the score “IQ”. But do IQ test really measure intelligence? Some IQ testers have argued that if IQ is genetically determined, then IQ must represent some sort of measure of innate ability. Twin concordance studies and other related studies comparing IQ of adopted children, their adoptive parents and their biological parents have indicated that, while heritability of IQ is probably greater than zero, it does NOT necessarily mean that IQ tests measure any “innate abilities”. Moreover, IQ tests have long been criticised for being unreliable and unrepresentative. So in the light of all these, there still have not been any really reliable test to measure intelligence, hence I would doubt anybody can claim that our kids will be more intelligent, etc. Evolutionists will of course argue the other way, claiming that as nature chooses the “fittest” to survive, natural selection must have put on selective pressure in favour of the more intelligent people. However, one must pay attention to the fact that selective pressure in the nowadays modern population is much much less than it used to be when people are gathering fruits or hunting animals for obvious reasons. In addition, even if people are becoming more intelligent, this does not mean that we can MAKE ourselves (or our kids) more intelligent in anyway, Nature does it, not us! From a biologist point of view, as our society becomes wealthier, people’s diet and education both improved dramatically over the last few decades, it is not surprising that people nowadays can “perform” better in those IQ tests, but it could as well be merely that our education system tends to emphasise and train our students to perform well in the areas that IQ tests rely on. Concerning your question about DNA/genetic modification, it is now possible experimentally to introduce new genes into a zygote so, apart from the ethical aspect, I cannot see why we cannot “modify” our next generation’s genome. Nevertheless, importantly, intelligence is NOT controlled by any single gene, it is polygenic (controlled by many genes) so it is virtually impossible to pin down all those related genes using present technology. As to the second part of your question, it is possible to change the DNA of some cells relatively “permanently”, and this is the central idea about gene therapy, e.g. introducing the gene for chloride channels back to the cells lining the respiratory epithelium of patients with cystic fibrosis using adenoviruses. However, intelligence is obviously controlled by our brain and involves billions of neurones wired up in a way even more complex than any maze you can imagine, so if we are already born, with our brain more or less developed, I don’t see any possibility to change the DNA of all the neurones in one’s brain to make oneself any smarter, at least not in the near future! :-) Joshua Chai Medical Student University of Cambridge, UK
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