Genetic modification and biotechnology
Techniques developed over last few decades Copying DNA – Polymerase Chain Reaction (PCR) Identifying people by DNA - DNA Profiling Mapping DNA – Gene sequencing, Human Genome Project Cutting and pasting genes – Gene transfer Cloning cells and animals
DNA Profiling Gel Electrophoresis Enzymes cut DNA into different size fragments Fragments are placed in a gel with an electric current The biggest, heaviest and least charged fragments move the least The smallest, lightest and strongest charged fragments move the most. A pattern is created that can be compared to someone else's pattern
Autoradiograph Who did it?
Gene probe A piece of DNA that is complementary to a certain gene can be added to the gel to see if that gene is present Ex. Sickle cell gene
PCR A lab technique, using a machine called a thermocycler, that can copy a small amount of DNA to make millions of copies. Can be used prior to gel electrophoresis
DNA profiling The process of matching an unknown sample of DNA to a known sample to see if they match, using gel electrophoresis. Crime scene Paternity How closely different organisms are related.
Gene Transfer Removing a gene from one organism and putting it into another organism. Possible because DNA is universal. In your book they use the example of removing a gene from fish that enables them to live in arctic cold waters and put it into tomatoes to allow them to grow in colder climates.
Bt corn - GMO Corn A gene is transferred to corn that causes the corn to produce a toxin that kills pests that would normally attack it. Name comes from a bacteria, Bacillus thuringiensis, which naturally produces the toxin.
Cloning Cutting, copying and pasting genes Sequences of bases can be cut using enzymes called endonucleases that look for certain sequences. If beginning and end of a gene are cut, it can be removed. Genes can be pasted into sequences using the enzyme DNA ligase, it recognizes the ends that are supposed to be together, called sticky ends, and attaches them.