Genetics as it applies to evolution, molecular biology, and medical aspects.
If the population reach an enormous quantity Is it possible to max out the gene pool, in which all variation of genetic is represented in each individual, and the people will eventually look the same?
I guess that in theory, in some very special circumstances, something like that might happen eventually. You would need an environment that has absolutely no changing factors. Alternatively, you'd need an environment that tolerates only one genotype. Eventually these should direct or force every organism living there into a very similar mold.
That wouldn't be "maxing out" anything, though. It would be more like "forcing out" or something, and it definitely would not contain all variation - it would lessen it drastically. Essentially everybody would be a clone, and any non-clonal person would be eliminated by the environment - be that some genome-scanning program or other factor that would do the trick.
In practise all this would be impossible, though.
"All variation" cannot be represented in each or any individual. You'd need an infinite genome for that!
No. DNA is an order of chaos. It can add or subtract itself, and is always changing/moving in a direction. Even if put in an environmental 'cage', it will still find a way to mutate itself and produce another variation.
i still don't get it, if there is a finite number of possible gene combination, and if the population greatly exceeds that finite number, then there must be an repetition of gene combination, which means that there will be two individuals possessing exactly same gene as each other right?
can you elaborate, and what rate is our gene mutating?
There are many mechanisms in place to protect the germline genome, but mutations do occur. There are single point mutations that can provide variation. There are inserts of nucleotides, and deletions of DNA that occur during DNA replication. And there are DNA viruses that like to insert themselves into our genome and "live" there, and are passed on if they get into the sex cells (germ cells). DNA is also being inverted (usually during DNA replication again) in certain sections causing variation. With the advent of epigenetics, we could have genes that have never been expressed, and are waiting for the opportune mutation to expresses itself. It is constantly changing (basically because we have to replicate the whole genome and this is not an exact function without errors, and in meiosis we even have recombination functions built in).
The possibility of different genotypes is astronomical (and in theory it is not even finite. Like said above, it can add or substract as well). But yeah, if you had an infinite number of individuals then there could be two identical copies just by chance. But for this you'd need to fill out half the universe with your model organisms. Or a bit less if they're bacteria, but still :)
Last edited by biohazard on Wed Jan 20, 2010 6:59 am, edited 1 time in total.
Yes, there would be variation still. But in effect an environment that had absolutely no changing factors would cause the evolutionary pressure to be constantly exactly the same - e.g. there would be only one optimal way to get food, one optimal way to escape predators and one optimal way to mate. I guess that would direct all individuals towards very similar genotype.
There would be mutations, still, but all the mutants would be less effective than the original version and lose out in competition.
Or at least this is how I reasoned it, am I missing something? :)
IMHO, if you wish to MAX out the genetic pool, than you're looking for individuals, who are differing, aren't you?
Anyway, imagine, that each of our genes has 2 alleles. So, if we take 20 000 genes, than you get 2^20 000 posibilities
Cis or trans? That's what matters.
Heh, I know. But the original post was a bit contradictory:
"Is it possible to max out the gene pool, in which all variation of genetic is represented in each individual, and the people will eventually look the same?"
So if you want everybody to look the same you need similar genomes but if you want to max out the gene pool, you have very different-looking people for sure :)
Although I think the original poster meant that each individual would have every possible gene in their genome and thus look the same, but that, I guess, we already concluded to be impossible.
I think the only way you could get everyone to look alike, is to clone one of them, and let all the others die out, or have everybody except one die and learn how to clone the one who did not die. Environmental pressures could do that I guess. But seems to me that the environment would have to be devoid of anything that contained DNA/RNA/Nucleotides, otherwise it would support the possibility of new material being integrated into the one original genome.
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