RECOMBINATION

This movie is made by Dr Nguyen Thanh Cong working at the Agricultural Genetics Institute in Hanoi, VIETNAM
Address below:
Dr Nguyen Thanh Cong
Molecular Biology Laboratory
Agricultural Genetics Institute
Vien Di truyen Nong Nghiep
Tuliem, Hanoi
VIETNAM

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Howto & Style

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• RECOMBINATION

[prchecker]

some great inforamtion here thanks

[FixerNK]

this is 1/3 models of recombination meselson something model I think...

[CommanderQ]

@tarascotti Despite there being specific DNA repair mechanisms for mismatched nucleotides, the very nature of DNA not matching exactly and then being replicated to produce two different copies is what makes evolution possible.

I suggest you take a look at Wikipedia's DNA mismatch repair page.

[tarascotti]

@CommanderQ it will remain attached to sugar and phosphate backbone but the bonding between nitrogenous bases will be easily broken and this doesn't happen with normal chromosomes if it were to happen in every crossing over then all chromosomes would remain broken at certain places. i hope you got it.

[CommanderQ]

@tarascotti The mismatched base would not be broken as you put it, as it is covalently linked to its neighbours by the phosphate backbone. The bonding between base pairs is simply hydrogen bonding. It takes about 12 kCal to disassociate a hydrogen bond, and about 400 kCal to disassociate a covalent one.

[CommanderQ]

@tarascotti There is a reason evolution takes such a long time. If you had a high number of variations, then it is entirely possible you'll end up repressing a functional protein, or simply stopping it from working. The mismatch would be resolved when DNA polymerase copies the two strands of DNA. The two template strands would create two different copied strands that differ where the mismatches were before.

[tarascotti]

@CommanderQ yeah but that mismatched base would then easily be broken and if majority of bases (eg 20 in 1 ) remains same then no variation would occur. there must be any further molecular mechanism behind this fact i m gonna ask this question to my teacher tomorrow.

[CommanderQ]

@tarascotti If you have one in 20 base pairs different, that is not going to make the helix become unstable. The majority is still similar.

[tarascotti]

@CommanderQ commanderQ your answer is wrong when there'd be mismatches then dna helix wouldn't remain stable and if there's no mismatch then there's no variation.

[tarascotti]

@CommonSense90 you are right i also dont understand it and also when two non sister chromatids exchange their dna segments they get paired with new strands it means it is correct base pairing as prior to crossover that results in no genetic variation. but still how do alleles shuffle ?? we need to find out this answer.