Cancer, Stem Cells, and DNA Technology CHAPTER 12 Uses of Recombinant DNA Technology Recombinant Techniques – Restriction Enzymes – Genetic Engineering/Gene

Cancer, Stem Cells, and DNA TechnologyCHAPTER 12Cancer, Stem Cells, and DNA TechnologyCHAPTER 12

•Uses of Recombinant DNA Technology• Recombinant Techniques

– Restriction Enzymes

– Genetic Engineering/Gene Splicing

– Achievements and Dangers of Recombinant DNA Technology

• DNA Fingerprinting and Gel Electrophoresis

• Polymerase Chain Reaction

• Human Genome Project

• Safety and Ethics

• Stem Cells and Cloning

• Cancer Genes, Prevention, and Risk

• This splicing process can be accomplished using restriction enzymes.

– These enzymes cut DNA at specific nucleotide sequences.

• These cuts produce pieces of DNA called restriction fragments

– That may have “sticky ends” that are important for joining DNA from different sources.

Restriction Enzymes Cut DNA in Specific Places

Recombinant DNA Techniques

• Plasmids are small, circular DNA molecules that are separate from the much larger bacterial chromosome.

Genes Can Be Spliced Into Plasmids












Figure 12.2

Recombinant DNA Technology (Genetic Engineering)

• Today, DNA technology is quickly replacing traditional plant-breeding programs.

– In the United States today, roughly one-half of the corn crop and over three-quarters of the soybean and cotton crops are genetically modified.

Applications of DNA Technology: GM Foods

• “Golden rice” has been genetically modified to contain beta-carotene.

– Our bodies use beta-carotene to make vitamin A.

Applications of DNA Technology: GM Foods II

• While transgenic plants are used today as commercial products, transgenic whole animals are currently only in the testing phase.

• These transgenic sheep carry a gene for a human blood protein.

– This protein may help in the treatment of cystic fibrosis.

• While transgenic animals are currently used to produce potentially useful proteins, none are yet found in our food supply.

• It is possible that DNA technology will eventually replace traditional animal breeding.

Applications of DNA Technology: “Pharm” Animals

Transgenic animals raised for the purposes of

producting pharmaceuticals are called pharm animals












DNA Fingerprinting and Forensic Science

• DNA technology has rapidly revolutionized the field of forensics.

– Forensics is the scientific analysis of evidence from crime scenes.

• DNA fingerprinting can be used to determine whether or not two samples of genetic material are from a particular individual.

– It can also show how related two organisms are to each other by the similarity of their DNA fingerprints

Figure 12.12

DNA Fingerprinting Generates Banding Patterns Unique to Individuals

1. Collect cells

2. Extract DNA

3. Cut the DNA in fragments using the same restriction enzyme

4. Separate the fragments using gel electrophoresis

The Polymerase Chain Reaction (PCR)

• The polymerase chain reaction (PCR) is a technique by which any segment of DNA can be copied quickly and precisely.

– Through PCR, scientists can obtain enough DNA from even minute amounts of blood or other tissue to allow DNA fingerprinting.

– A single DNA molecule can be replicated in a test tube to make 30 million identical copies in a few hours

– Formerly DNA fingerprinting was not possible because too little DNA was available at a crime scene

Polymerase Chain Reaction: DNA Replication in a Test Tube

Exponential Increase in the Number of DNA Molecules each Cycle












The Human Genome Project

• In 1990, an international consortium of government-funded researchers began the Human Genome Project.

– The goal of the project was to sequence the human genome so scientists could have roadmap for finding genes

Safety and Ethical Issues• Safety

– Moving genes into other organisms could create hazardous new pathogens

– Strict laboratory safety procedures have been designed to protect researchers from infection by engineered microbes

– Concerns of GM Foods

• Crops carrying genes from other species might harm the environment.

• GM foods could be hazardous to human health.

• Transgenic plants might pass their genes to close relatives in nearby wild areas.

• Should genetically engineered human growth hormone be used to stimulate growth in HGH-deficient children? To stimulate growth in normal children, making them tall enough to excel in basketball or volleyball?

• Should we try to eliminate genetic defects in our children?

• Advances in genetic fingerprinting raise privacy issues. Who should have access to your genetic information?

– Should medical insurance companies know if you are genetically likely to develop cancer?

Ethical Issues About Biotechnology












Therapeutic Cloning and Stem Cells

• Stem cells are early-stage cells that can develop into any organ or tissue of the body.

• If the right chemical signals can be added to stem cells, they can potentially grow into replacement organs.

• Stem cells can be taken from a fetus after abortion, from umbillical cord blood, or from adult stem cells (such as those that form blood cells)

Cloning

• A clone is a genetic duplicate of an existing organism

• Many plants are easily cloned by taking a piece of the plant and cultivating it

Cloning a carrot

Reproductive Cloning of Animals

• Nuclear transplantation

– Involves replacing nuclei of egg cells with nuclei from differentiated cells.

– Has been used to clone a variety of animals.

• Scottish researchers cloned the first mammal in 1997.

– Dolly, the sheep, was the product of their work.

• The procedure that produced Dolly is called reproductive cloning.

Figure 11.13

The Cloning of Dolly the Sheep












Figure 11.18

Cancer Genes (Oncogenes) Result From Damaged Proto-Oncogenes

Unrestricted mitosis resulting in

tumors (cancer)

Cancer Risk and Prevention

• Cancer

– Is one of the leading causes of death in the United States.

– Breast, lung, colon, skin, and prostate cancers most common

• Examples of carcinogens

– UV radiation

– Tobacco

– Alcohol

– Certain chemicals like formaldehyde, radon gas


•Uses of Recombinant DNA Technology

• Recombinant Techniques• Restriction Enzymes


• Genomics and Proteomics

• Gene Therapy


•Cancer Genes, Prevention, and Risk


Documents

Cancer, Stem Cells, and DNA Technology CHAPTER 12 Uses of Recombinant DNA Technology Recombinant Techniques – Restriction Enzymes – Genetic Engineering/Gene