DNA Technology

Quick Review DNA is a double helix made of monomers called nucleotides. There are 4 bases- A, T, C, G DNA carries the code used by the cell to make proteins. DNA is unique to individuals and can be altered resulting in new proteins.

DNA Fingerprinting Restriction Enzymes These are enzymes that are used to cut DNA at specific sequences. The enzyme will cut the DNA each time it comes into contact with the specific sequence. Restriction enzymes can be used to cut DNA smaller for purposes of identification and also to rearrange DNA.

Gel Electrophoresis Process used to create a DNA fingerprint. Uses a gel through which DNA travels. The purpose is to separate the pieces of DNA based on their size. Smaller pieces move faster and farther down the gel then the larger pieces.

Gel Electrophoresis How it’s done: The DNA sample is first cut into pieces by the restriction enzyme. The pieces are then placed into a hole in the gel called a well. The gel is placed into a special box with a buffer inside. Charges are used to pull the DNA through the gel. (DNA has a negative charge.)

Gel Electrophoresis If 2 bands are in the same position on the DNA fingerprint, you know 2 things: 1. The DNA strands are the same size. 2. The 2 bands have the same number of nucleotides.

What’s it used for? Crime scene analysis (victim/suspect) Find out parental identity Identifying/cataloging endangered species Analyzing relationship of dead individuals Anastasia Tomb of the Unknown solider

Read a Fingerprint Can you identify the suspect that was at the crime scene?

Parental Analysis All DNA fragments must be accounted for in the baby from Mother or father. Any stray DNA fragments not from mother or father means one of them is not the parent.

What’s the difference? How are the “rules” for identifying an individual at a crime scene or a missing person, different from those of determining paternity (matching a baby to parents)? An individuals bands will match up exactly. When comparing to parents, a child will have bands from each which makes it more difficult to compare.

Genetic Engineering Also known as recombinant DNA. Restriction enzymes are also used to cut DNA in order to put it back together in a new combination. A small ring of DNA called a plasmid that comes from bacteria is often used to transport a desired gene to a new cell.

Genetic Engineering The Process: 1. A plasmid is removed from a bacteria cell and is cut with a restriction enzyme. 2. The gene that codes for the desired trait is located and removed from its natural source. The same restriction enzyme used on the plasmid is used here, to remove the gene. 3. The two cut pieces of DNA (plasmid and isolated gene) are allowed to stick back together.

Genetic Engineering 4. The newly altered plasmid is inserted into a cell that will make the desired trait 5. The modified bacteria is allowed to reproduce and pass on the new trait to its daughter cells.

Applications of Genetic Engineering Agricultural Engineering- Drought resistant corn (being tested in CA), pesticide resistant crops, biofuels, vaccine/antibiotic carrying plants GMO’s- Blue roses (modified with pansy gene), Venomous cabbage (venom from scorpion), Glofish (Fluorescent gene from jellyfish and sea coral), Bacteria used to produce human insulin Human Engineering Cloning, “Designer babies,” Gene therapy

Human Genome Project The project was completed in April of 2003, 2 years ahead of schedule and under budget. Its main goal was to catalogue every gene on each chromosome of the human. Since completion, 1,800 genes for diseases have been discovered. Some animal/insect genomes have also been completed.

Uses for the Human Genome A person’s genome can be used to determine whether or not they have a genetic disease. Gene therapy can be used to treat disease. A therapeutic gene can be used to replace the mutated gene.

Examples of Gene Therapy Gene therapy is being used in many ways: 1. The CFTR gene has been identified as the cause of cystic fibrosis. Experiments have been conducted to replace the gene with a normal copy. Lung cells are that to be the best to use, but a method of introduction has not been determined. 2. A therapeutic gene called ADA has been successfully used in the bone marrow cells of patients with SCID (Severe Combined Immunodeficiency). Their immune systems were corrected and the 6 patients went on to live normal lives.