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In this video i'm going to talk about the one gene one enzyme hypothesis.
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The one gene one enzyme hypothesis was proposed by two scientists named tatum and beedle in 1941.
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And they based this off of their work with a bread mould called neurospora crasser.
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And what we have here at the bottom is showing a simplified pathway for arginine synthesis.
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A substrate is converted by an enzyme into ornithine.
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Ornithine is then converted by another enzyme into citraline, which is then finally converted by another enzyme into arginine.
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Now, due to their work with this bread mould, neurospora, tatum and beedle came up with the idea that one gene encodes for a single enzyme which affects a single step.
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Gene a would encode for enzyme a.
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Gene b would encode for enzyme b and gene c would encode for enzyme c.
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Each enzyme affecting a different step in the metabolic pathway that leads to the synthesis of arginine and each of these enzymes being encoded for by a separate gene.
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Now, what happens if one of these genes is mutated to not function or is missing? tatum and beedle did some experiments with this by irridating with x -rays various samples of neurospora.
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So, for example, say you have a sample of neurospora that makes citraline, but not arginine...