1.When was the first time when a DNA sample solved a criminal case?
It happened in 1986, when professor Alec Jeffrey compared two samples of DNA and solved the case.
2.What are enzymes used for in DNA process?
Enzymes are used to "cut and paste" DNA.
3.What organisms have been cloned already?
Many plant and animal species have been already cloned, but a human being has not, and probably will not in the close future, due to ethical issues.
Five main factors from the reading:
1.Genes can be cloned in recombinant plasmids.
2.Cloned genes can be stored in genomic libraries.
3.Reverse transcriptase can help make genes for cloning.
4.Nucleic acid probes identify clones carrying specific genes.
5.Recombinant cells and organisms can mass-produce gene products.
Diagram:
Link: http://www.cdc.gov/ncidod/eid/vol4no2/kordick.htm
Summary:
The introduction of the chapter talked about DNA and crime scene investigations. It gave us the first case in which DNA solved a criminal case, by comparing a sample of DNA left at the crime and a sample taken from the person who did it. It also explained us what DNA technology is. It is the methods for studying and manipulating genetic material and it has rapidly revolutionized the field of forensics, the scientific analysis of evidence for legal investigations. The next part of the chapter talked about that genes can be cloned in recombinant plasmids. Although it may seem like a modern field, biotechnology, the manipulation of organisms or their components to make useful products, actually dates back to the dawn of civilization. In the 1970s, the uses of biotechnology exploded with the invention of methods for making recombinant DNA in the laboratory. Recombinant DNA is formed when scientists combine nucleotide sequences (pieces of DNA) from two different sources-often different species-to form a single DNA molecule. To manipulate genes in the laboratory, biologists often use bacterial plasmids, which are small, circular DNA molecules that replicate separately from the much larger bacterial chromosome. Because plasmids can carry virtually any gene and are passed on from one generation of bacteria to the next, they are key tools for gene cloning, the production of multiple identical copies of a gene-carrying piece of DNA. Gene-cloning methods are central to genetic engineering, the branch of biotechnology that involves the direct manipulation of genes for practical purposes. Enzymes are used to "cut and paste" DNA. In the gene-cloning procedure, a piece of DNA containing the gene of interest must be cut out of a chromosome and "pasted"into a bacterial plasmid. The cutting tools used are bacterial enzymes called restriction enzymes. Cloned genes can be stored in genomic libraries. Most bacterial clones consist of identical cells with recombinant plasmids carrying one particular fragment of target DNA. The entire collection of all the cloned DNA fragments from a genome is called a genomic library. Reverse transcriptase can help make genes for cloning. The DNA that results from such a procedure, called complementary DNA, represents only the subset of genes that had been transcribed into mRNA in the starting cells. Nucleic acid probes identify clones carrying specific genes. Recombinant cells and organisms can mass-produce gene products. DNA technology has changed the pharmaceutical industry and medicine. It is mostly used for therapeutic hormones, such as insulin, diagnosis and treatment of disease, and vaccines. Genetically modified organisms are transforming agriculture. Genetic engineers have produced many varieties of genetically modified organisms, ones that have acquired one or more genes by artificial means. If the newly acquired gene is from another species, the recombinant organism is called a transgenic organism. However, genetically modified organisms raise concerns about human and environmental health. Gene therapy may someday help treat a variety of diseases. One reason to tamper with the human genome is the potential for treating a variety of diseases by gene therapy - alteration of an afflicted individual's genes. The analysis of genetic markers can produce a DNA profile. The most important application of biology to forensics is DNA profiling, the analysis of DNA fragments to determine whether they come from a particular individual. The PCR method is used to amplify DNA sequences. Cloning DNA in host cells is often the best method for preparing large quantities of DNA from a particular gene. However, when the source of DNA is scanty or impure, the polymerase chain reaction (PCR) is a much better method. Gel electrophoresis sorts DNA molecules by size. Many approaches for studying DNA molecules make use of gel electrophoresis. This technique uses a gel as a molecular sieve to separate macromolecules - usually proteins or nucleic acids-on the basis of size, electrical charge, or other physical properties. STR analysis is commonly used for DNA profiling. Repetitive DNA consists of nucleotide sequences that are present in multiple copies in the genome; much of the DNA that lies between genes in humans is of this type. DNA profiling has provided evidence in many forensic investigations. RFLPs can be used to detect differences in DNA sequences. Genomics is the scientific study of whole genomes. The Human Genome Project revealed that most of the human genome does not consist of genes. The whole-genome shotgun method of sequencing a genome can provide a wealth of data quickly. Proteomics is the scientific study of the full set of proteins encoded by a genome. Genomes hold clues to the evolutionary divergence of humans and chimps.
Key Terms:
1.Biotechnology - the manipulation of organisms or their components to make useful products.
2.DNA technology - methods for studying and manipulating genetic material.
3.Plasmids - small, circular DNA molecules that replicate separately from the much larger bacterial chromosome.
4.Gene cloning - the production of multiple identical copies of a gene-carrying piece of DNA.
5.Genetic engineering - the branch of biotechnology that involves the direct manipulation of genes for practical purposes.
6.Restriction site - the DNA sequence recognized by a particular restriction enzyme.
7.Genomic library - the entire collection og all the cloned DNA fragments from a genome.
8.Vaccine - a harmless variant or derivative of a pathogen that is used to stimulate the immune system to mount a defense against the pathogen.
9.Gene therapy - alteration of an afflicted individual's genes.
10.DNA profiling - the analysis of DNA fragments to determine whether they come from a particular individual.
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