G-T Mismatch Repair
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G-T Mismatch Repair
Whenever a G -T mismatch is encountered in DNA, the cell repairs it using a specific mechanism which has a bias towards replacing T with C instead of replacing G with A. This helps in reducing mutations.
But the question is - how does the cell know that it has to selctively replace T with C in a G -T mismatch and how exactly it reduces mutations ?
Why does the cell replace only T and not G ?
Why is the cell always so confident about the correct presence of G at a G-T mismatch ?
But the question is - how does the cell know that it has to selctively replace T with C in a G -T mismatch and how exactly it reduces mutations ?
Why does the cell replace only T and not G ?
Why is the cell always so confident about the correct presence of G at a G-T mismatch ?
Re:
Yeah, 5-methyl cytosine gets spontaneously converted into thymine and in every case where it happens the G is correctly placed and T is wrong.
But G-T mismatches can be formed due to some other reasons too ( e.g. replication errors) and there it is possible that the 'G' is incorrectly placed and 'T' is correct. Then replacing T will only create more mutations after each replication. How does the cell handle that?
But G-T mismatches can be formed due to some other reasons too ( e.g. replication errors) and there it is possible that the 'G' is incorrectly placed and 'T' is correct. Then replacing T will only create more mutations after each replication. How does the cell handle that?
- MrMistery
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the cell just assumes the T came from methylcytosine. It's not 100%, and in some cases it does result in a mutation, but in most cases the initial base pair is restored.
"As a biologist, I firmly believe that when you're dead, you're dead. Except for what you live behind in history. That's the only afterlife" - J. Craig Venter
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