Human Genetics: Concepts and Applications (Lewis), 9th Edition

Chapter 19: Genetic Technologies: Amplifying, Modifying, and Monitoring DNA

Chapter Outline

CHAPTER OVERVIEW

1. Biotechnology uses altered cells or molecules for various applications.
2. A transgenic organism contains foreign DNA.
3. Recombinant DNA technology was the first of the modern biotechnologies.
4. Bioethics questions, gene patenting, and potential uses and risks of biotechnology raise legal questions for society.

1. The polymerase chain reaction (PCR) can amplify selected DNA in a manner similar to the way DNA replication works in the nucleus.
2. The PCR method involves repeated cycles of denaturation of double stranded DNA, annealing of primers, and DNA synthesis using heat stable DNA polymerases.

1. Recombinant DNA technology (i.e. gene cloning) was the first of the modern biotechnologies.
2. Guidelines for using recombinant DNA technology were first drawn up at a 1975 meeting in Asilomar, CA.
3. Since that time, biotechnology has proven a safe and effective research tool.

1. Recombinant DNA is made by covalently linking foreign DNA with the DNA of a cloning vector such as a plasmid or virus.
2. Restriction enzymes are used to cut DNA molecules.
3. Recombinant DNA is most often amplified by introducing it into a bacterium or other single cell host.

1. Bacteria and other single cell organisms are also used as hosts of DNA libraries.
2. DNA libraries can be constructed from DNA fragments of chromosomes (genomic libraries) or can contain only processed coding sequences when mRNA is used as the source of the genetic information (cDNA libraries).
3. DNA probes are used to identify and isolate specific DNA fragments of interest from DNA libraries.

1. Phenotype selection can be used to identify host cells with recombinant DNA.
2. A popular technique identifies host cells with recombinant DNA using antibiotics and a color test.

1. The products of recombinant DNA technology are used in health care, food technology, agriculture, and forensics.
2. Recombinant DNA technology can be used to produce human proteins such as insulin, interferon, and tissue plasminogen activator (tPA).
3. The textile industry has benefited from bacterial production of indigo.

1. Human proteins are generally best expressed in Eukaryotic cells.
2. Transgenic animals have been genetically engineered to produce human proteins in their milk.
3. Creating transgenic animals is more challenging than creating transgenic plants.

1. Genetically engineered animals are used in research to study the function of genes during normal development and as models for human diseases.
2. The use of transgenic animals as models of human diseases has limitations.

1. Recombinant bacteria can be used to clean up toxic waste such as oil or heavy metals.

1. Gene chips, gene expression DNA microarrays, are applications of genetic technology.
2. Microarrays can be prepared which analyze the entire genome.
3. These techniques are useful in medical and research applications.

1. RNA interference (RNAi) involves the production of small interfering RNAs (siRNAs) that affect the translation of messenger RNAs.
2. Laboratory research now uses siRNAs to "knock down" production of certain proteins.
3. RNAi may be used for medical therapy in the future.
4. Researchers use DNA-like molecules, termed morpholinos, to block splicing mutations. With the splicing mutation bypassed, normal protein may be produced.
5. Knockouts are used to study the effects of inactivated genes on development. Knockins are used to study the effects of altered genes.
6. Knockout mice are an important animal model for studying diseases human disease.