Yesterday: Genetic Disorders and Gene Therapy Today: Genetic Engineering Contemporary Issue – Genetic Disorders and Gene Therapy Lesson Goals To understand the nature of genetic diseases. To differentiate between chromosomal and single gene diseases. To understand the nature of Down Syndrome and diagnostic methods to detect it. To understand the important points of heredity including dominant and recessive alleles. To understand how to predict heredity using a Punnett square. To understand the nature and heritability of Huntington Disease, Cystic Fibrosis, and Sickle Cell Disease. To understand the nature of genetic testing and it’s future application to diagnose diseases and the probability of getting genetic diseases. To understand the nature of gene therapy and it’s future application to cure diseases. Key Terms; chromosome chromosomal disease meiosis nondisjunction Down syndrome karyotype amniocentesis autosomal disease gene allele dominant recessive co-dominant widow’s peak genotype phenotype Huntington disease cystic fibrosis sickle cell disease

What does Genetic Engineering mean to You?

Overview of Genetic Engineering What are the differences between cloning, recombinant DNA, and genetic engineering? What are the tools we use for genetic engineering? Plasmids Restriction Enzymes DNA Ligase

Cloning Involves Making Identical Copies “Cloning” can mean several things: To make many identical copies of a DNA molecule or a particular stretch of DNA (DNA cloning or molecular cloning). To replicate an entire organism (reproductive cloning). Cloning Involves Making Identical Copies In the simplest terms, cloning is the creation of a genetically identical copy of an original organism. Plants are relatively easy to clone. Most people are familiar with the use of cuttings or stem segments (such as the “eyes” of potatoes) to create new plants. Technically, the new plants are clones of the original, because they are genetically identical to the parent plant. In the wild, many different kinds of plants and animals use forms of reproduction that copy an exact genotype. This type of reproduction (which is seen in grasses, strawberry plants, sponges and flatworms, for example) often is referred to as asexual reproduction. Even fraternal twins can be thought of as clones, because they have identical sets of DNA. Molecular biologists use the term “cloning” to refer to a variety of processes that involve making identical copies of part or all of a DNA molecule, a single cell type, or an entire organism. DNA cloning technology, also referred to as molecular cloning, recombinant DNA, or gene cloning, is a common practice in molecular laboratories today. A DNA fragment from one organism is introduced into a self-replicating element (host) such as a bacterial plasmid. Molecular biologists use DNA cloning to create many identical copies of a DNA molecule or to isolate a particular stretch DNA (which involves making identical copies of the DNA of interest). In 1997, scientists used a somatic cell (a cell that is not an egg or sperm cell) from an adult sheep to produce a reproductive clone via a process called somatic cell nuclear transfer (SCNT). With this technique, scientists transferred the nucleus from a somatic cell of an adult sheep into an egg from which the nucleus had been removed. This type of cloning, called reproductive cloning, still is very rare and difficult to achieve for vertebrate animals. SCNT also is used in therapeutic cloning to produce many copies of stem cells. Stem cells are undifferentiated cells that can be used as replacement cells to treat a variety of diseases and disorders. The purpose of this type of cloning is not to produce another organism, but to generate copies of cells in sufficient quantities for research and medical treatments. References Campbell, N. E., & Reece, J. B. (2002). Biology (6th ed.). San Francisco: Benjamin Cummings. Fulka, J., First, N. L., Loi, P., & Moor, R. M. (1998). Cloning by somatic cell nuclear transfer. BioEssays. 20:847-851. Human Genome Project. (2004). Human genome project information. Retrieved 10-26-2004 from http://www.ornl.gov/sci/techresources/Human_Genome/elsi/cloning.shtml

Recombinant DNA Recombinant DNA is when two or more pieces of DNA that don’t normally go together are combined.

Genetic Engineering Genetic Engineering is the process of using recombinant DNA technology to genetically alter or create new organisms.

Recombinant DNA Technology Tools Plasmid Vectors To move DNA from one organism to another. Restriction Enzymes “Molecular Scissors” to cut DNA in specific places. DNA Ligase DNA “glue” to stick pieces of DNA together.

Plasmids Plasmids Small, circular pieces of “extra” DNA found in bacteria. Plasmids often carry antibiotic resistance.

Restriction Enzymes: Molecular Scissors A restriction enzyme (RE) is a specialized protein that cuts DNA in a very specific place. Different REs cut at different places along the nucleotide sequence.

Recombinant DNA Cell DNA DNA fragment ligated (inserted) into vector creating recombinant DNA molecule. DNA Ligase (Glue)

Today Gene Therapy Vector Engineering Project. Use paper models to simulate the process of engineering your recombinant gene therapy vector. DNA sheet for the therapeutic gene to treat the genetic disease you were assigned. DNA sheet for the vector you chose to treat the disease.

Materials In lab folder (one per group): Get from me (one per group): Activity Instruction Sheet (WHITE) Answer/Data Sheet (WHITE) Restriction Enzyme Sheet (GREEN) Get from me (one per group): Vector DNA sheet (PINK) Therapeutic DNA sheet (BLUE) Other: scissors/glue stick