Can gene mutation be predicted?

[Homo_sapiens]

First off, this is my very first post. Forgive any errors.

 

I am curious to know if genetic mutations can be predicted within a given population, given a certain amount of time.

 

I can certainly understand that predicting exactly what mutation will occur could very well be nearly impossible. I am, however, interested in knowing if we can say that a mutation could probably happen within X number of years, within a population number of X. The population most likely will not remain a constant, but perhaps if we knew the size of a given population to begin with it might affect the prediction going out any number of years?

[jimmydasaint]

I'm sorry I can't add much value to your very first post (but welcome to the Forum anyway). In my haste, I will refer you to this article and see if it helps you. I think past observations of mutations suggest some predictability.

 

We know little about the distribution of fitness effects among new beneficial mutations, a problem that partly reflects the rarity of these changes. Surprisingly, though, population genetic theory allows us to predict what this distribution should look like under fairly general assumptions. Using extreme value theory, I derive this distribution and show that it has two unexpected properties. First, the distribution of beneficial fitness effects at a gene is exponential. Second, the distribution of beneficial effects at a gene has the same mean regardless of the fitness of the present wild-type allele. Adaptation from new mutations is thus characterized by a kind of invariance: natural selection chooses from the same spectrum of beneficial effects at a locus independent of the fitness rank of the present wild type. I show that these findings are reasonably robust to deviations from several assumptions. I further show that one can back calculate the mean size of new beneficial mutations from the observed mean size of fixed beneficial mutations.

http://www.genetics.org/cgi/content/full/163/4/1519

[Mr Skeptic]

To some extent. Mutations are random, so predictions need to be statistical in nature; you can't really predict a specific mutation in advance any more than you could, say, predict Joe's IQ from the average IQ of Americans. However, it is known that mutation rates vary between different genes, both because there is stronger error-correction on them and because if you mess up certain genes it means certain death.

 

So yes, to some extent mutations can be predicted and I think some biologists even try to use it as a dating system (to guess at how long ago two lineages split, for example).

 

Also, if you cause a point mutation that disables a very important (but not vital) gene in a bacteria, eventually you can expect that it will revert back. While the mutation that would revert the change may be as likely as a mutation anywhere else that might make it "worse", that particular mutation would cause a tremendous increase in fitness (fixing a broken important gene) and so if/when it does happen, the bacteria with it will have a tremendous selective advantage.

[CharonY]

The mutation estimation is fairly easy. Assuming no preferred site the chance of a mutation in any given locus is 1/number of loci. To get the time you just have adjust for mutation rate (i.e. number of mutations in a given time frame). The tricky (and more interesting) bit is actually to estimate which mutations will persist.

Edited June 8, 2010 by CharonY

[Double K]

There is currently an effective testing proceedure out there, but it's around $3500 US per test, and is patented and not easily available.

 

http://7pmproject.com.au/2952.htm

American firm Myriad Genetics owns the patent to two mutated genes linked to breast and ovarian cancer.

 

It grants Genetic Technologies Limited exclusive license in Australia to test for breast cancer.

 

But a cancer advocacy group is challenging that monopoly, arguing genes are discovered, not invented, and therefore should not be patentable.

 

It follows the success of a similar case in the United States.

 

"There's a philosophical and ethical issue about commercialising the human body and its genetic material," lawyer Rebecca Gilsenan told the ABC.

 

"Gene patents can have the effect that they stifle research, they can stifle the development of treatments that researchers might otherwise develop and they can impede access to diagnostic testing for that gene mutation."

 

And there is a list of their products and what they have the capability to test for here:

http://www.myriad.com/products/

[CharonY]

I assume that the test is a simple PCR (the whole story is a tad off-topic, though).

[Double K]

Sorry wasn't trying to take it off topic, however I don't think it is entirely off topic, the OP was "can gene mutation be predicted?"

 

I agree that who owns a patent right to a gene is off topic, but the point was to lead to the things which can be tested for.

 

As to how they are done exactly that's outside my realm of knowledge, so I've just pointed down that path.

[CharonY]

Well the method is to determine different (known) variants of a given gene. So in fact there is no prediction involved.

[Homo_sapiens]

Thank you all for your help! I really appreciate the knowledge everyone has shared.

 

It is interesting we use gene mutations as a dating method. I wonder how accurate such a procedure really is.

[CharonY]

Uh, it is not a dating method per se (i.e. you do not use it to date something). Rather the inverse is true. You use (calibrated) mutation rates to estimate e.g. when two sequences diverged.

This is also referred to as molecular clocks. The critical point is generally the means of calibration.