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Asked by josh to Alan, Caspar, Diana, Murray, Sarah on 15 Mar 2011 in Categories: General.
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Caspar Addyman answered on 14 Mar 2011:
Yes, I think so.
The best way to find genes (as far as I know) is to look sequences of DNA that are the same across different species or sometimes across lots of individuals in one species. If a section of DNA is the same in lots of cases then the chances are that it does something important. But we might not necessarily know what it does.
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Alan Winfield answered on 15 Mar 2011:
Hmm. I’m not sure I understand the question. Do you mean if a gene is not expressed? When a gene is expressed it means that it has an effect on the organism. So if a gene for red hair is expressed then it means you have red hair, if it’s not then you don’t (note: I made that up – I’m not even sure there is a gene for red hair). But if a gene is not expressed, then yes, it is still a gene. Think of it as an instruction that hasn’t been read – it’s still an instruction.
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Diana Drennan answered on 15 Mar 2011:
If a gene is never shown, then there will be no natural selection on it, and no pressure to stay functional. So, it would probably eventually become mutated to the point where it wasn’t a gene anymore. That’s part of how evolution works. For instance, if a gene gets copied, and we really only need one of them to work, the second gene is free of pressure to stay working the same way and can mutate. Most of the time that leads to something that doesn’t work at all, but sometimes it leads to something that makes the organism better (healthier, more likely to reproduce). Our DNA is full of copies that don’t work anymore and things like that.
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Sarah Thomas answered on 15 Mar 2011:
Well we have big bits of DNA which don’t actually do anything, so these aren’t genes, they are probably just the result of lots of evolution.
But the rest of it does all code for genes even if they are genes which our body never really needs to use, or if they do something that we don’t ever see or understand.
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