Selective Breeding • Nonrandom mating to select for characteristics in parents that are desired in the offspring. • Eg. Breeding domestic animals, domestic crops- corn
Genetic Engineering • Direct manipulation of genes to alter hereditary traits. • Advances in technology have enabled scientists to use several different techniques to study and alter DNA sequences.
Restriction Enzymes • Discovered in bacteria. • Enzymes cut the DNA at short, specific sequences. • Some restriction enzymes cut the DNA leaving strands that over hang called “sticky ends” • For example: G A A T T C • C T T A A G
Recombinant DNA • Scientists can use sticky ends to join together segments of DNA from two different organisms, which is called recombinant DNA. • Foreign DNA is put into a plasmid, a circular piece of DNA found in bacteria.
Foreign DNA Plasmid with foreign DNA plasmid Enzymes cut plasmid and foreign DNA The desired DNA segment is inserted into the plasmid.
Transgenic organisms • The plasmid with the new DNA can be inserted into a new organism. • This is creates a transgenic organism
Agricultural uses: genetically modified organisms (GMO) • To give crops disease/ drought resistance, add nutrients, etc • FlavrSavr tomato: modified to ripen slower • Golden rice: rice with added genes to make Vitamin A
Medical uses: Gene therapy • Genetic diseases are often caused by genes that do not function properly. • Scientists can add a functioning gene into a plasmid and insert it into the patient. • Testing treatment for Cystic Fibrosis- missing one gene.
Gel Electrophoresis Method used to separate DNA fragments based on their charge and size. Create an agarosegel with wells at the top of each lane. Add DNA samples into each well. Electric current pulls DNA towards positive end of the gel.
Gel electrophoresis cont. • DNA segments separate by size. • The longer segments move slower so they stay at the top and the shorter segments move faster and are at the bottom.
Gel electrophoresis cont. A “ladder” is also added in another lane. It is made of DNA fragments of known sizes. It acts like a ruler to measure the unknown fragment lengths.
DNA Fingerprinting • A technique used to analyze DNA. Can compare or identify similarities between samples of DNA. • Use enzymes to cut DNA samples into segments. • Everyone has different length segments because of random repeated sequences.
Filter DNA through an agarose gel by the process called gel electrophoresis. • Compare the pattern of the DNA bands . • Matching lengths will appear at the same distance.
Cloning • Remove the nucleus from an egg cell. • Replace with a nucleus from the individual to be cloned. • The cell will divide into an embryo.
Implant embryo into a surrogate mother. • The offspring that is born will be a genetic clone (not related to surrogate mother).
Dolly was the first animal to be successfully cloned. She was cloned by Ian Wilmut, Keith Campbell and colleagues at the Roslin Institute in Edinburgh, Scotland. Born July 5, 1996 Died Feb 14, 2003