A carbon atom with four different substituents is said to be asymmetric, and asymmetric carbons are called chiral centers

Chiral carbon most distant from the carbonyl carbon has the same configuration as the chiral carbon in D-glyceraldehyde.

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#Unit 13. Methods in Biology

In case of hotstart PCR, After the reaction mixture is prepared, primers can pair to the single-stranded regions in a nonspecific manner. 

A more attractive alternative is to cover the reaction mixture with a plug of inert wax and place the critical reagent on top of this plug. 

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#Unit 13. Methods in Biology

A more attractive alternative is to cover the reaction mixture with a plug of inert wax and place the critical reagent on top of this plug. 

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#Unit 13. Methods in Biology

Oligonucleotide-directed mutagenesis

The basic PCR mutagenesis system involves the use of two primary PCR reactions to produce two overlapping DNA fragments, both bearing the same mutation in the overlap region; this technique is thus termed overlap extension PCR .

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#Unit 13. Methods in Biology

Oligonucleotide-directed mutagenesis.

This technique requires a knowledge of nucleotide sequence, since an oligonucleotide may then be synthesized with the base mutation. 

Annealing of the oligonucleotide to complementary (except for the mutation) single-stranded DNA provides a primer for DNA polymerase to produce a new strand and thus incorporates the primer with the mutation.

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#Unit 13. Methods in Biology

Molecular beacons gives an idea for annealing.

#Id: 2598

#Unit 13. Methods in Biology

TaqMan assay gives an idea for alleles in Real time PCR.