Back in February 2003 bioethicist Gregory Stock gave a TED talk where he speculates that biotechnology - particularly genetic engineering and individually tailored personalized medicine - will ultimately "drive" our evolution:
He thinks the human genome project was the first step in revolutionizing medicine, unravel the aging process, allow us to modulate our emotions, and generally improve human life. He thinks human cloning - "birth of a delayed identical twin" - will happen in 5 or 10 years, and be "no big deal". All of that seems pretty straightforward.*
Anyway, he then goes on to what I would consider the very speculative part of his thesis: embryo selection and genetic engineering that will drive human evolution. He talks about selecting embryos that don't have the risk of manic depression, and screening for a desired personalities, which ignore the role of the environment, in addition to our genes.
Even more speculatively, he thinks that the technological solution to introducing genetic changes in our offspring will be the development of an extra artificial chromosome that can be used "program" parents' genetic preferences in their offspring. It's not clear to me how that would work exactly - adding new genes won't necessarily override the genetic program that's already present. If both parents are brown-eyed, it's unlikely that simply adding new DNA sequences will override the genetic code in their offspring that drives the synthesis of brown eye pigment. The problem becomes even more difficult when a trait is affected by many genes.
And it's not clear to me how genetic modification, which he notes will likely be reserved for the wealthy, will drive human evolution in any meaningful way if the majority of humans don't have access to the technology. How will such changes spread in the population when parents with different numbers of chromosomes often produce infertile offspring? Perh
Of course I'm not the only one who has pointed out such issues. The review Stock's 2002 book on the subject, Redesigning Humans: Our Inevitable Genetic Future (amazon.com, indiebound.com), in Science makes it sound like he has taken some of those issues into account, so I'm not sure how he envisions genetic engineering carried out by a tiny segment of the population significantly affecting human evolution. I suppose I should read his book.
It's worth nothing the pace of biotechnological development is very difficult to predict. Back in 1998, Stock claimed that human germline engineering "will be a realistic option within a decade or so." Here we are, more than a decade later, and I don't see human germline engineering becoming an option in the immediate future, both for technical and ethical reasons.
* Except for the "no big deal" part - some people still think hormonal birth control is a big evil deal, and that's been around for nearly 50 years. In vitro fertilization also has loud detractors. I doubt the people who are against control of human reproduction today will quickly jump on the cloning bandwagon. He does note that some people will be against human genetic engineering for religious, ethical or other reasons. I suppose the question is whether those people will have a significant effect on the adoption of the technology.
Tags:genetic engineering, human evolution