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Plant Sciences, Zoology & Evolution / Re: How does natural selection work?
« on: 18/03/2022 21:25:35 »
Hi.
The main details for natural selection have already been presented. Most DNA alterations are just random mutations etc.
I haven't studied Biology for years but this was one of the more "funky" or convention-defying contemporary ideas that was discussed back in the day. It's useful to suggest that your DNA doesn't always dictate what you do, sometimes it can be the other way round....
There's a small chance that DNA transcription to produce proteins isn't always a one-way process. There are viruses with RNA reverse transcriptase enzymes so that RNA can be converted to DNA. This opens the door to the possibility that information may sometimes flow in that direction from RNA to DNA which might then get incorporated into the nuclear DNA of the cell.
Lets take a simple model: A host organism has a physically demanding environment in which it must survive and to do this it is using a lot of muscle and this exercise is building more muscle in the usual way. This means there is a lot of RNA in the cytoplasm that encodes for muscle proteins. If a virus gets on board, some of that RNA can be reverse transcripted into DNA which could end up getting incorporated into the nuclear DNA stores. The host organism now has two (or more) copies of the gene encoding for the muscle protein, so they are likely to get a higher transcription rate of RNA encoding for that protein from then onward. This means there has been a permanent change in the amount of muscle protein the organism will synthesize - but, more importantly, if that change has occurred in the germ cells of the organism then this change is passed on to future generations.
The effect is minor, if it happens at all, but it's interesting. It's the possibility that the actions of the organism during its life might influence the DNA. The whole set of circumstances falling into place, like accidental incorporation into the nuclear DNA, would only be a one-in-a-million chance but that is precisely the sort of scale we're talking about for evolution over many years. It probably isn't going to be the main route for evolution but it could be a boost to the process.
Best Wishes.
The main details for natural selection have already been presented. Most DNA alterations are just random mutations etc.
I haven't studied Biology for years but this was one of the more "funky" or convention-defying contemporary ideas that was discussed back in the day. It's useful to suggest that your DNA doesn't always dictate what you do, sometimes it can be the other way round....
There's a small chance that DNA transcription to produce proteins isn't always a one-way process. There are viruses with RNA reverse transcriptase enzymes so that RNA can be converted to DNA. This opens the door to the possibility that information may sometimes flow in that direction from RNA to DNA which might then get incorporated into the nuclear DNA of the cell.
Lets take a simple model: A host organism has a physically demanding environment in which it must survive and to do this it is using a lot of muscle and this exercise is building more muscle in the usual way. This means there is a lot of RNA in the cytoplasm that encodes for muscle proteins. If a virus gets on board, some of that RNA can be reverse transcripted into DNA which could end up getting incorporated into the nuclear DNA stores. The host organism now has two (or more) copies of the gene encoding for the muscle protein, so they are likely to get a higher transcription rate of RNA encoding for that protein from then onward. This means there has been a permanent change in the amount of muscle protein the organism will synthesize - but, more importantly, if that change has occurred in the germ cells of the organism then this change is passed on to future generations.
The effect is minor, if it happens at all, but it's interesting. It's the possibility that the actions of the organism during its life might influence the DNA. The whole set of circumstances falling into place, like accidental incorporation into the nuclear DNA, would only be a one-in-a-million chance but that is precisely the sort of scale we're talking about for evolution over many years. It probably isn't going to be the main route for evolution but it could be a boost to the process.
Best Wishes.
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