I’ve seen where scientists have been trying to do gene therapy on adults (not embryos) by injecting DNA into cells using a virus. While smaller effects like changing hair color or changing the amount of a hormone that is produced are possible, are larger changes realistic?
In Sci-Fi, if you inject some DNA and you can radically change someones body in a matter of seconds. I don’t think that’s realistic, but is it possible to change a persons body in a large structural way after they become an adult?
By large structural changes, I mean like making someone bigger/smaller, change their ethnicity, add/remove limbs, change gender, or even switch species.
I’m not an expert, but I’d assume that the body altering the skeletal structure would be difficult and time consuming, if possible at all.
And on a side note, what is the maximum genetic material that could be inserted, and could an entire genome be feasibly replaced in a mechanical sense?
Almost certainly not. By way of analogy, I have genes which code for, among other things, having two arms. But I might suffer some freak accident and lose an arm. In that case, I would still have all of the two-arms genes, but I would nonetheless be stuck with having a single arm for life. Now ask yourself, what’s the difference between a person who grew up with two arms but then got a gene transplant to have four arms, and a person who naturally grew up with four arms but lost two of them in an accident? Why would the one grow two new arms, but not the other?
Actually, Chronos, there are cutting-edge techniques that would allow regrowth of a lost limb. This patient’s severed finger was regrown in four weeks.
Obviously this technique is somewhat crude and nowhere near the scale that Jiggy is talking about, but it sure seems promising at this point. I’m not sure if it would ever get to the point where you could change someone’s gender, species, or even ethnicity, but given this recent breakthrough I couldn’t declare it impossible.
Very cool; I did not know that. Still, those techniques aren’t based on changing the genome of the patient: It’d be no harder to grow an extra limb on an adult with or without the DNA for it.
Well, it would be potentially possible to slowly alter an organism at the dult stage, by altering what stage they were at. You’d have to change most of an organism’s cells, but for many it won’t matter; you have to avoid making so many changes that the body cells dont’ recognize each other and cal out the imune system, though.
If you then created another puberty trigger and sent the organism back through it, you could acheive some impressive changes in its phyiology. Many species have much mroe differences between adult and child forms than we. Adding whole arms would be pretty tough, because the bone structure would have to change very much and get in the way of organs. You could probably get as far as human-animal forms, however, since all that involves is elongating and shortening pre-existing bones and altering hair follicles.
Adding things like glowing skin shouldn’t be hard at all, in theory.
True, it doesn’t change the genome of the patient, but it does show that we can fool the body into going back into a building phase well into adulthood.
That doesn’t necessarily mean the body can be induced to tear down existing tissue with the old DNA structure and rebuild anew, but heck, it doesn’t mean it’s impossible either.
Shortening bones is going to involve some pretty extensive surgery. Even if you could induce the bone cells in a particular area to demineralize the bone, you’d be looking at a long time with casts or implants for reshaping. Lengthening is probably not going to happen much after (real) puberty, because the growth plates ossify and that’s a no-turning-back process (unless you go through the trouble to remove some bone mechanically and establish a new population of bone cartilage cells in the gap. For that much invasive work, you might as well just grow a new bone in vitro and implant it.
Modifying tissues with high turnover, like hair and skin and intestinal lining, would be much, much easier. The easiest things would involve the expression of new proteins in secretions without changes in development and structure. I’m thinking green fluorescent hair and skin, sweat that’s inhospitable to bacteria (or just decreased sweat production), or many more practical things.
Changing your hair texture would be difficult, because you’d have to kill off all of your old follicles and induce the growth of new ones in different shapes. So you’d spend a lot of time bald in the name of beauty.
Or let’s say you want to be orange, so you get a gene that makes your skin cells concentrate beta carotene. Suddenly you need a lot more vitamin A in your diet…
It’s very cool, but I can imagine the annoyances are endless.
It would be much MUCH MUCH more complicated than the average layman would think, if you’ll forgive the slight patronage. Partly because there’s still a huge amount of details we don’t understand about development on the molecular level, and partly because trying to rewrite that information once we fully understand would probably be a much larger problem. Then there are the issues of delivery, expression, self-immunization, etc, etc, etc. It would involve a major rewrite. Sorry, no wings for you any time in the foreseeable future.