Naked Science Forum
Life Sciences => Cells, Microbes & Viruses => Topic started by: another_someone on 09/02/2008 17:16:11
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I was listening on the Radio (BBC7 - on the Internet) to a biography of Gregor Mendel.
One thing was mentioned which struck me (although I don't know how accurate it was - I would not expect 100% scientific accuracy from such a source). This was that prior to Mendel's promotion of the idea of genetics, the prevalent theories of the time regarded inheritance as a continuum - that if you successfully hybridize an organism with trait X with and organism with trait 2X, you would get offspring with trait 1.5X. The difference with the genetic model is that with genetics, you cannot get organisms with 1.5X, but rather you get a distribution of probabilities of offspring with trait X and trait 2X (OK, this is complicated by the interaction of genes, and the multiplication of genes effecting one trait - but in crude terms, and for a few simple traits, even in absolute terms, that is the case). This seemed to be to draw a close parallel with the shift from classical mechanics, which judged a continuum of action and energy levels, with quantum mechanics that allowed only certain specific energy states, and a spectrum of probabilities of finding a particle in one state or another.
I am not trying to draw conclusions from the analogy, merely highlighting the the apparent analogy to exist (although it would be interesting to speculate about conclusions - maybe this would relate to Ian's (Soul Surfer's) position on evolutionary cosmology (http://www.thenakedscientists.com/forum/index.php?topic=11668.0)?
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Interesting.
You say that 1.5X cannot happen. I'm wondering if that's true in all cases. What about in the case of mutations where parts of genes become disconnected? To use a QM analogy, that would be like part of a photon coming away.
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Interesting.
You say that 1.5X cannot happen. I'm wondering if that's true in all cases. What about in the case of mutations where parts of genes become disconnected? To use a QM analogy, that would be like part of a photon coming away.
Part of a gene cannot be disconnected. A gene creates a protein, and it either creates that protein or it does not.
There are two cases where I understand you can have 1.5X (no doubt someone will tell me I am wrong in some detail, but I believe I am probably right in the generality - but even there, I may be overconfident):
When you have multiple copies of a gene (e.g. you have two copies of a gene, and only inherit one). But this does not undermine the quantum nature of the event, it just reduces the quantum size.
The other area is probably closer to what you are talking about (but it is not an question of inheritance, but of mutation, which is slightly different), and that is where the gene mutates to create the same amount of protein, but the protein is distorted in some way, and behaves less efficiently, so behaves as if less of the protein was being made (ofcourse, if this protein a modulator for a second gene, it could effect the expression of a second gene, that would have the effect of less of the second genes output being produces, but not because less of the second gene was inherited). Ofcourse, the mutation could also have the opposite effect - either the protein could become more efficient, or if the protein, rather than switching another gene on, could switch another gene off, but switch it off less efficiently.
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George - sorry. For some reason I was thinking chromosome, not gene.