Dna Technology/ Genetic Engineering

DNA Technology/ Genetic Engineering

Objectives 5. The genetic composition of cells can be altered by incorporation of exogenous DNA into the cells. As a basis for understanding this concept, students know: a. the general structures and functions of DNA, RNA, and protein. b. how to apply base-pairing rules to explain precise copying of DNA during semi-conservative replication, and transcription of information from DNA into mRNA. c. how genetic engineering (biotechnology) is used to produce novel biomedical and agricultural products. d.* how basic DNA technology (restriction digestion by endonucleases, gel electrophoresis, ligation, and transformation) is used to construct recombinant DNA molecules. e.* how exogenous DNA can be inserted into bacterial cells in order to alter their genetic makeup and support expression of new protein products.

Selective Breeding • Selective breeding produces organisms w/ desired traits. • Inbreeding - mating between closely related individuals - Ex. Dog show or horse race

Test Cross • A cross of an individual of unknown genotype w/ an individual of known genotype(usually, homozygous recessive).

• _____ x bb = ? • Ex. BB x bb => all Bb • Bb x bb => Bb & bb

What is genetic engineering? • Manipulation/ alteration of genes to change the protein products expressed in an organism. Ex. A glow-in-the-dark plant

Recombinant DNA • Made by connecting or recombining fragments of DNA from different sources. • Plasmid = circular bacteria DNA • Restriction enzyme = cuts DNA • Gene splicing = ligating or connecting DNA fragments

Gel Electrophoresis • How does it work? -separates DNA fragments by size & charge -small fragments move faster & large fragments lag behind -neg. charged DNA is repelled by neg. charge and attracted to positive charge.

Application of Gel Electrophoresis • DNA fingerprinting - determine whether sample DNA matches DNA from a specific source Ex. Forensic science & paternity testing • DNA sequencing -determine the order of nitrogen bases of DNA

Human Genome Approximately 80,000 genes on the 46 human chromosomes. • Maps are currently being prepared that show the locations of • known genes on each chromosome.

Gene Therapy • inserts a normal copy of the gene into cells to compensate for abnormal genes OR to make a functional protein. • A gene that is inserted directly into a cell usually does not function. • Vector (virus) = a carrier that delivers the gene.

Cloning • Clones – genetically identical copies. • Therapeutic cloning - clone organs or cells • Cloning of genes • Cloning of animals

Transgenic organism • Definition: An organism (typically a mouse) that is engineered to carry a foreign gene, or transgene of choice as part of its own genetic material. • Purpose: Very useful for understanding the function of newly discovered genes & for producing useful proteins

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Method: The gene of your interest is first isolated and recombinant DNA is created. - The transgene of choice is then injected into a fertilized egg. - These eggs are then transplanted back into a surrogaate female, in which they can develop to term.