First of all, I know this sounds like a stupid question, but bear with me, a friend and I were wondering the other day if there’s any truth to the idea of radioactivity or genetic manipulation causing a mutation in an adult human (or another animal, as long as its been born already). You know, like in the movies or comics when they tamper with someone’s genes and turn them into monsters or give them superpowers, I know that’s just fiction but what I’m asking is if its possible at all to mutate someone, in any way, AFTER birth instead of before birth.
My friend insists that its possible, but I’ve never heard of it and I was under the impression that all radioactivity will do to adults is give them ancer…
Well, sure. The problem is that mutagens do not act in tandem. In other words, radioactivity will not affect the same gene in every cell so the damage is random. This won’t cause you to be able to spin webs or stick to walls.
Gene therapy, on the other hand, is the attempt to do exactly what you’re asking. The field is still young but there have been some major advances over the years. Of course the idea behind gene therapy is to correct an incorrect gene or otherwise lessen the damage of incorrect genes rather than allowing us to climb up walls.
Um, various types of cancer are caused by mutations. Sometimes the person was born with the defective (mutated) gene copies, other times, over time or due to yes, things like radiation, a normal gene mutates and is not/cannot be repaired by the cells.
I think the OP is specifically asking about changing a particular gene, or adding a new gene, into all cells (or relevant cells) to cause some desired effect.
Oh, any info is welcome really. Thanks to yorick’s answer I’m reading on gene therapy and it appears that its quite risky even when used to cure a disease- apparently it can cause side effects worst than the original problem they wanted to cure…
It’s still a young field and there are a lot of potential techniques in use in the lab. Very few have translated into therapies so far but a few are in phase II or III trials as we speak. There are viral and non-viral techniques to get a gene into cells. One hot field right now is zinc finger nucleases and other similar proteins that can, in theory, snip out a specific gene inside of a cell and result in the insertion of the correct copy of the gene…or an enhanced version of a gene. Needless to say these are many years away from the clinic but it’s fascinating stuff.
Keep in mind that a lot of genes are only “read” during development, so even changing them in every single cell in an adult body won’t have any apparent effect, except in future offspring.
In a sense, yes, many types of cancers are in essence the result of mutations. It may be that the animal was born with defective copies of the gene, or that they mutated and the repair mechanisms were not able to repair/keep it in check (none are 100% perfect).
I do not want to use singular for those because cancer is really a term grouping a large number of diseases, and different mutations are associated with each type.
-Yes, mutations happen after birth. They happen all the time, in fact. There is never a point where your DNA somehow becomes protected from damage and change.
-The vast majority of these mutations do nothing. Most DNA is noncoding, and even amongst protein-coding genes, in any given terminally differentiated cell, there are only a relative handful of genes that are active and doing stuff.
-If a mutation actually manages to do something, by far the most likely outcome is cancer. Actually, I’d guess that it’s probably more likely that the cell in question will just die, but we don’t really notice that, so I don’t know what the rate of spontaneous apoptosis due to mutation is.
-If you’re thinking of something like you see in science fiction, where a change to someone’s DNA causes their body to change - let’s say something simple, like growing a tail - then that’s just not going to happen. As has been said, developmental genes - those that direct what your final body is going to look like - are generally only read during development. As an analogy, consider DNA like a blueprint for a building. Let’s say you’ve built a lovely hotel. It’s up and running and guests are visiting. And now you decide you really wanted to have a pool, but it wasn’t in the plans. So you go back to the blueprints and draw in a pool. Would you then look out the window, expecting the pool to be there? No, of course not. The process of adding on a pool after the hotel is built is very very different from the process of building the pool in with the hotel in the first place. As far as we know, DNA doesn’t really have a “let’s go back and add something in” feature. Life as we know it hasn’t evolved that capability. There are seeming exceptions, like lizards regrowing tails or insect metamorphosis, but those are specific developmental features that were designed in from the beginning. If you want to change a human into, say a werewolf-like creature, you’re going to have to invent a whole new type of developmental program, and that’s far more than can be introduced with simple mutation. You’re talking about redesigning the entire organism from bottom up.
What I’m getting from all your answers and what I’ve read about gene therapy, is that it’s conceivable, yet extremely difficult and risky, and not likely to go far anytime soon. That correct?
Let’s not forget that mutations can also occur in the germ cells, the ova and sperm (and the cells that generate sperm). These can be passed on to offspring, and, if they are, will be in every cell of the child’s body and may cause real changes. However, like most mutations, most of these are harmful, and will either cause conception to fail, or miscarriage, or (occasionally) a non-viable or unhealthy baby. Other mutations may have no noticeable effect, but just a few may actually cause advantageous adaptations. It is via these rare advantageous mutations in the germ line that evolution occurs.
Even advantageous mutations that are passed on to offspring, however, generally do not have very spectacular or noticeable effect. Even someone who is carrying a new, advantageous gene mutation destined to be naturally selected for, and to spread through the species over the subsequent generations, usually will not seem very obviously different from anybody else. They won’t have superpowers or tails or anything. Maybe (to give one example of a relatively recent advantageous human mutation) they will be able to do something like be able to digest lactose even after infancy.
What/when is the most recent of all?
I presume there are different ways to define them. The entire human species is not able to digest lactose after infancy.
