Naked Science Forum

Life Sciences => Plant Sciences, Zoology & Evolution => Topic started by: nassar on 19/04/2011 21:30:02

Title: Can radiation cause beneficial mutations?
Post by: nassar on 19/04/2011 21:30:02

Nasser asked the Naked Scientists:
   
Mutation occurs quite naturally through mistakes made in copying your DNA. When your cells divide mutations introduce more variety into the genes of a species in terms of survival... this makes it more likely to survive and breed. (ref: AQA Science, Nelson Thornes p.112).

My question is, can nuclear radiation not only cause cancer but also possibly cause mutation so that future generations become better adapted to the environment?

What do you think?

Title: Can radiation cause beneficial mutations?
Post by: graham.d on 21/04/2011 09:02:35

The answer is probably mostly negative for humans and other mammals but maybe more beneficial to simpler organisms that reproduce more rapidly. If there is high levels of damage to DNA then the chances of humans reproducing at all can fall very rapidly. With simpler oraganisms, they can suffer a high failure rate yet still produce many offspring, some of whom may have a randomly gifted survival advantage. This may even include better survivability to high levels of radiation!

Title: Can radiation cause beneficial mutations?
Post by: Dasyatis on 21/04/2011 19:47:26

This may seem like a neat idea (and indeed many comic book heroes gain their powers through some type of radiation mutating their genes), but graham hit the nail on the head. Natural mutations do not often change large portions of the DNA. Radiation is more likely to cause an overload of mutations that ultimately terminates cell function, or begin to replicate uncontollably (i.e. cancer). Also, to actually benefit from radiation, it would have to affect the germ cells for organisms that reproduce sexually (eggs or sperm) that are then passed on to offspring. In very small doses you may be able to produce non-lethal mutations in offspring, but you cannot predict what those mutations will do.

In time, if radiation levels consistenly rise in the environment, it is possible (and indeed suggested by evolutionary theory) that adaptations will begin to pop up that increase fitness under those conditions. What those adaptations will be, and what life-forms will actually adapt can only be speculated. Bacteria will likely show the first signs of adaptation due to asexual reproduction and high replication rates. Bacteria evolved to eat a synthetic material (nylon) in less than a century, so I'm sure they can do anything.