Pre-AP Biology Ch.12 Ms. Haut Biotechnology Pre-AP Biology Ch.12 Ms. Haut

DNA technology has many useful applications The Human Genome Project The production of vaccines, cancer drugs, and pesticides Engineered bacteria that can clean up toxic wastes Copyright © 2003 Pearson Education, Inc. publishing Benjamin Cummings

DNA and Crime Scene Investigations DNA and Crime Scene Investigations Many violent crimes go unsolved For lack of enough evidence If biological fluids are left at a crime scene DNA can be isolated from them

DNA fingerprinting is a set of laboratory procedures DNA fingerprinting is a set of laboratory procedures That determines with near certainty whether two samples of DNA are from the same individual That has provided a powerful tool for crime scene investigators Investigator at one of the crime scenes (above), Narborough, England (left)

BACTERIAL PLASMIDS AND GENE CLONING Plasmids are used to customize bacteria: An overview Gene cloning is one application of DNA technology Methods for studying and manipulating genetic material

The Bacterial Chromosome One double-stranded, circular molecule of DNA Located in nucleoid region, so transcription and translation can occur simultaneously Many also contain extrachromosomal DNA in plasmids

Binary Fission

Plasmids Short, circular DNA molecules outside the chromosome Carry genes that are beneficial but not essential Replicate independently of chromosome en.wikipedia.org/?title=Plasmid

R Plasmids Contain genes that confer antibiotic resistance Medical consequences: resistant strains of pathogens due to overuse of antibiotics http://www.slic2.wsu.edu:82/hurlbert/micro101/images/AntibioticSelection.gif

Bacteria as Tools Bacterial Transformation— Uptake of DNA from the fluid surrounding the cell Causes genetic recombination

Transformation Biotech companies use this technique to artificially introduce foreign genes into bacterial genomes (human insulin, human growth hormone)

Researchers can insert desired genes into plasmids, creating recombinant DNA And insert those plasmids into bacteria (transformation) Figure 12.1

Bacterial clone carrying many copies of the human gene 1 Isolate DNA from two sources Human cell E. coli If the recombinant bacteria multiply into a clone The foreign genes are also copied 2 Cut both DNAs with the same restriction enzyme Plasmid DNA Gene V Sticky ends 3 Mix the DNAs; they join by base-pairing 4 Add DNA ligase to bond the DNA covalently Recombinant DNA plasmid Gene V 5 Put plasmid into bacterium by transformation 6 Clone the bacterium Bacterial clone carrying many copies of the human gene

Restriction Enzymes Used to “cut and paste” DNA Used to “cut and paste” DNA The tools used to make recombinant DNA are Restriction enzymes, which cut DNA at specific sequences DNA ligase, which “pastes” DNA fragments together

Genes can be cloned in recombinant plasmids: A closer look Bacteria take the recombinant plasmids from their surroundings And reproduce, thereby cloning the plasmids and the genes they carry

Cloned genes can be stored in genomic libraries Genomic libraries, sets of DNA fragments containing all of an organism’s genes Can be constructed and stored in cloned bacterial plasmids or phages Figure 12.4

Nucleic acid probes A short, single-stranded molecule of radioactively labeled or fluorescently labeled DNA or RNA Can tag a desired gene in a library

CONNECTION Recombinant cells and organisms can mass-produce gene products Applications of gene cloning include The mass production of gene products for medical and other uses Table 12.6

Genetically modified organisms are transforming agriculture New genetic varieties of animals and plants are being produced A plant with a new trait can be created using the Ti plasmid

Biotech companies can artificially induce transformation of bacteria

“Golden rice” has been genetically modified to contain beta-carotene This rice could help prevent vitamin A deficiency Figure 12.18B

Drought resistant corn Flavr Savr Tomato (CalGene)

Transgenic organisms Are those that have had genes from other organisms inserted into their genomes Different organisms, including bacteria, yeast, and mammals Can be used for this purpose Figure 12.6 These sheep carry a gene for a human blood protein that is a potential treatment for cystic fibrosis

CONNECTION DNA technology is changing the pharmaceutical industry DNA technology is changing the pharmaceutical industry DNA technology Is widely used to produce medicines and to diagnose diseases

DNA technology is changing the pharmaceutical industry and medicine Hormones, cancer-fighting drugs, and new vaccines are being produced using DNA technology This lab equipment is used to produce a vaccine against hepatitis B Figure 12.17

Therapeutic hormones In 1982, humulin, human insulin produced by bacteria Became the first recombinant drug approved by the Food and Drug Administration Figure 12.7A

Diagnosis and Treatment of Disease Diagnosis and Treatment of Disease DNA technology Is being used increasingly in disease diagnosis Vaccines Is also helping medical researchers develop vaccines Figure 12.7B