Evolution question, please?
I understand how natural selection works; certain genes are removed from the gene pool to favor survival. But the original genes were there all along.
That is why people can create new breeds of dogs, for instance. There were originally "proto -dogs" that had all the genes that now define the different breeds. The non great dane genes, for instance, were bred out. But how were all the genes put into their genetic code in the first place?
I am not trying to be controversial. I just don't have an answer for where the new genes come from, or how frequently mutations result in traits that enhance survival.
How frequently does a genetic mutation result in a positive survival trait? Are there any documented mutations that have been included into a breed, for instance?
- pzifissshLv 71 decade agoFavorite Answer
"I understand how natural selection works; certain genes are removed from the gene pool..." "There were originally "proto-dogs" that had all the genes that now define the different breeds. The non great dane genes, for instance, were bred out."
That's one I've never heard before! I'm so used to explaining to people why there is no such thing as a gene FOR being, say, a great dane, that I'm somewhat at a loss for how to explain that there is no such thing as a gene for NOT being a great dane.
Genes are neither "for" nor "against" any visible trait. Genes are instructions for making proteins. Proteins are not only what you are made of, but they also play an active role in the chemistry of life. You are what you are because of the complex ways in which your proteins all interact with one another, and with your genetic material.
If you offspring receives a mutation in just one gene---if just one of his/her proteins is different in some subtle way from yours, that single change could have many different effects (hair color, length of fingers, susceptibility to some disease), or just one effect, or none at all. And if there is some particular trait of interest (length of fingers for example), there might be several or many different genes that affect it.
The original genes were NOT there all along That's what mutation is, it changes genes, and it can do more than that. It can add or delete genes as well. Remember what I said about proteins interacting with the genetic material itself. It's that interaction that causes the DNA to be transcribed and duplicated. If a mutation alters a protein that is relevant to that process, it could conseqently ALTER the PROCESS by which DNA is transcribed and replicated.
How often do new "survival traits" arise? It need not be often. The thing about a "survival trait" is that it survives. Fatal mutations, on the other hand don't. No matter how seldom favorable mutations occur, it's still the favorable ones that are vastly more important than the unfavorable ones, because the favorable ones are the ones that are amplified by the whole process of evolution, while the unfavorable ones are quickly suppressed.