2 Genetic Engineering Techniques Restriction Enzymes:Genes can be cut at specific DNA sequences by proteins known as Restriction EnzymesEach recognizes and cuts DNA at a particular sequence (area of Bases)They are INCREDIBLY accurate, they will ONLY cut the area that they recognizeThis amazing ability allows us to cut DNA into fragments so that we can isolate it, separate it, and/or analyze it.
4 Restriction EnzymeA restriction enzyme is an enzyme that cuts double-stranded DNA at a specific recognition nucleotide sequences (A, T, C, G) known as restriction sites.Such enzymes, found in bacteria, are thought to have evolved to provide a defense mechanism against invading viruses.Restriction enzymes are required when removing or replacing genesThey are also very important in the creation of recombinant DNA
6 Genetic Engineering Techniques DNA RECOMBINANT:Literally means “combined DNA”DNA fragments cannot function all by themselves.They must be part of the genetic material of living things cells before the genes they contain can be activated.In this, second step of genetic engineering, the DNA fragment must be put into a hosts cells
7 Genetic Engineering Techniques DNA RECOMBINANTS:DNA fragments (cut by restriction enzymes) may be combined with bacterial DNA so that they can later be inserted into a bacterial cellThe small, circular DNA molecules in bacteria (called plasmids) can be removed and cut with a restriction enzyme.The cut ends are sticky to the foreign fragment, and can allow for the formation of a recombinant DNA molecule
8 DNA RecombinationDNA recombination is sometimes called gene splicing, because the genes are “cut & pasted”The new DNA strand created is considered to be artificial, because it would not normally occur in natureBenefit of all life using the exact same DNANot the same thing as “natural” genetic recombinationThis how we engineer drugs to combat bacterial resistance (like MRSA) and how we are able to make non-human organisms make things like human insulin
9 Genetic Engineering Techniques DNA INSERTION:During the first 2 steps of genetic engineering, DNA fragments containing the desired gene are obtained and then inserted into DNA that has been removed from the recipient cell (the cell where the DNA is going.)Forming recombinant DNA (New DNA)
10 DNA Insertion & Cloning To insert the DNA into LIVING cells it is easiest to use bacteriaBacteria in a solution of salt and the desired DNA will eventually take up the DNA in its own DNA.This is considered DNA insertionThese new bacteria are then cultured (grown) into a large colony.The technical term for a large number of cells grown from a single cells Clone.So this is DNA cloning.You don’t HAVE to use bacteria but it is the easiest.
13 Genetic Engineering Techniques DNA sequencing:Sequencing DNA is when you read the nitrogenous bases (ATCG) along the length of the DNA fragment.Only one strand of the double helix is used to sequence the DNAneed multiples of the used strand (So you clone it)The DNA’s bases are tagged using different chemical treatments that break the pieces and reveal the Base sequence.By tagging the bases, we are able see the order of A, T, C, & G and are then able to read the base sequence
15 Gel electrophoresisDuring gel electrophoresis, DNA is cut with a restriction enzyme into small piecesBecause DNA has a slight negative charge, different charges are placed at either end of a gel containing tray.When the DNA is placed into the tray it will slowly move across the gel (towards the +)Because the pieces are different sizes they move at different speeds (large = slower).
16 DNA FingerprintingThe amazing complexity of the human genome ensures that NO TWO INDIVIDUALS are exactly the same.This biological theory allows for a powerful new tool in criminal investigationsNow, finding bodily fluids and/or skin cells at the scene of a crime or on a victim can link a suspect to a crime with amazing reliability.
20 Genetic Engineering Techniques Transgenic (means gene from across species)It is now possible to insert genes from one organism into another.Organisms that contain such foreign genes are said to be Transgenic.Trans- across or moved genesRequires many of the already mentioned genetic engineering techniques (most of them)This allows us to create organisms with foreign traits
21 This transgenic animal is the result of placing jellyfish genes in an albino rabbit, and then bathing it in UV light
22 Transgenic PlantsIt is through the process of genetic engineering that we have most of the plants that we use for food.Not only can we selectively breed more productive organisms, but we can use transgenic organisms to make plants that are resistant to diseases, insects, drought, winds, etc.