Presentation on theme: "Manipulation of DNA. Restriction enzymes are used to cut DNA into smaller fragments. Different restriction enzymes recognize and cut different DNA sequences."— Presentation transcript:
Restriction enzymes are used to cut DNA into smaller fragments. Different restriction enzymes recognize and cut different DNA sequences at specific nucleotide sequences. http://www.biotechlearn.org.nz/themes/dna_l ab/restriction_enzymes How are restriction enzymes used in the manipulation of DNA?
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/2645/formats/print.htm
What do restriction enzymes have to do with gel electrophoresis? http://hopes.stanford.edu/diagnsis/gentest/f_s02gelelect.gif They are used to cut the DNA into small segments
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.
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
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