Manipulation of DNA

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Manipulation of DNA
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How are restriction enzymes used in the
manipulation of DNA?

• Restriction enzymes are used to cut DNA into
  smaller fragments.
• Different restriction enzymes recognize and cut
  different DNA sequences at specific nucleotide
  sequences.

•  

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riction_enzymes
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• How is gel electrophoresis is used to analyze
  nucleic acids and proteins and to distinguish
  between two alleles of a gene? 

• Gel electrophoresis is used to separate
  macromolecules like DNA, RNA and proteins.
• DNA fragments are separated according to their
  size.
• Proteins can be separated according to their size
  and their charge (different proteins have
  different charges).

(a) Electrophoresis of nucleic acids. (b) An
agarose gel loaded with six digested DNAs and
stained http//openlearn.open.ac.uk/file.php/26
45/formats/print.htm
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What do restriction enzymes have to do with gel
electrophoresis?
They are used to cut the DNA into small segments
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lelect.gif
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When is gel electrophoresis used to separate DNA
fragments?

• Gel electrophoresis can be used for a number of
  purposes. Examples include
• To get a DNA fingerprints in forensics
• To get a DNA fingerprint for paternity testing
• To get a DNA fingerprint so that you can look for
  evolutionary relationships among organisms
• To check a PCR reaction. The purpose of PCR,
  (Polymerase Chain Reaction), is to make a large
  number of copies of a gene. This is necessary to
  have enough starting template for sequencing.
• To test for genes associated with a particular
  disease.

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Describe RFLP analysis.

• Restriction fragment length polymorphism or RFLP
  analysis is used to identify a change in the
  genetic sequence that occurs at a site where a
  restriction enzyme cuts.
• RFLP is a term that refers to a variation in a
  sequence of DNA that is detectable through gel
  electrophoresis
• RFLPs can be used to trace inheritance patterns,
  identify specific mutations, and played a
  critical role in mapping the human genome
• Newer faster techniques are replacing RFLP
  analysis

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Challenges of RFLP Analysis

• Need relatively large DNA sample
• Complex
• Time consuming
• Not precise enough to identify all DNA markers
  and differences
• Being replaced because PCR techniques