2011年2月17日木曜日

Ch. 12 DNA Technology and Genomics

HOW IS CLONING RELATED TO THE MOVIE "THE ISLAND"?
The movie "island" was about cloning genes. Clones were all told that they would eventually able to go to the place called the island. They believed that the island must have been like heaven. However, Lincoln, the main character, found out that it was a lie. They are clones and originals pay the company so they can be donated. For example, one lady who cannot get pregnant cloned herself and donated her husband's sperm to get her clone pregnant. As soon as the clone gave a birth, she got killed. This is what the company was having as its business. Although DNA cloning has many advantages, I think cloning a human should keep be forbidden. Because once a cloned human is made, it will be one complete person even though it is a copy of somebody. It does not matter if it should get killed after the business or not, I don't think it is a good idea to clone a human.

HOW DOES DNA FORENSICS WORK?
Any type of organism can be identified by examination of DNA sequences unique to that species. Identifying individuals within a species is less precise at this time, although when DNA sequencing technologies progress farther, direct comparison of very large DNA segments, and possibly even whole genomes, will become feasible and practical and will allow precise individual identification.
To identify individuals, forensic scientists scan 13 DNA regions, or loci, that vary from person to person and use the data to create a DNA profile of that individual (sometimes called a DNA fingerprint). There is an extremely small chance that another person has the same DNA profile for a particular set of 13 regions.

WHAT ARE THE ADVANTAGES AND DISADVANTAGES OF DNA TECHNOLOGY?
Advantages: DNA technology is mostly accurate, and it is easy to analyze. Some are not too expensive. Also the process can get done rapidly. Higher precision and accuracy.
Disadvantages: You might have to suffer some issues. Sometimes it is very expensive. If it makes a little tiny mistake, it can lead to a huge problem. It can still be developed so it is not completely done yet.



SUMMARY:
DNA technology was first used to solve a double murder in England. Today, it has been developed and used a lot more often mainly for solving crimes. Gene cloning leads to the production of multiple identical copies of a gene carrying piece of DNA. Recombinant DNA is formed by joining DNA sequences from two different sources. One source contains the gene that will be cloned. Another source is a gene carrier. Steps of gene cloning:1, plasmid DNA is isolated. 2, DNA containing the gene of interest is isolated. 3, Plasmid DNA is treated with restriction enzyme that cuts in one place, opening the circle. 4, DNA with the target gene is treated with the same enzyme and many fragments are produced. 5, Plasmid and target DNA are mixed and associate with each other. 6, Recombinant DNA molecules are produced. 7, The recombinant DNA is taken up by a bacterial cell. 8, The bacterial cell reproduces to form a clone of cells. Enzymes are used to cut and paste DNA. Restriction enzymes cut DNA at specific sequences and DNA ligase paste DNA fragments together. Genomic libraries can store cloned genes. It can be constructed with many different types of vectors, such as plasmid library, phage library, and BAC. Nucleic acid probes bind to cloned DNA. Screening a gene library explain; bacterial clones are transferred to filter paper. Cells are lysed and DNA is separated into single strands. A solution containing the probe is added, and binding to the DNA of interest is detected. The clone carrying the gene of interest is grown for further study.
DNA technology now can be used as pharmaceutical industry and medicine. Therapeutic hormones, and diagnosis, vaccines, and treatments of disease are the products of DNA technology. With recombinant DNA products, identity to human protein, purity, and quantity are able to be taken as advantages. Gene therapy may someday help teat a variety of diseases. It aims to treat a disease by supplying a functional allele. It may be a good treatment for cancer, especially. In order for gene therapy to work, we will need to take a challenge of safe delivery to the area of the body affected by the disease, and achieving a long lasting therapeutic effect. Advantages of PCR are; it can amplify DNA from a small sample, and results are obtained rapidly, and reaction is highly sensitive, copying only the target sequence.
DNA profiling has provided evidence in many forensic investigations. Forensics, establishing family relationships, indentification of human remains, and species identification are examples. Genomics is the study of an organism's complete set of genes and their interactions. Evolutionary relationships can be elucidated. Determination of the nucleotide sequence all DNA in the human genome, and identification of the location and sequence of every human gene are the goals of the human genome project now.


KEY TERMS:
1) Gene engineering: manipulating genes for practical purposes
2) Plasmids: small, circular DNA molecules independent of the bacterial chromosome that are used as vectors
3) Restriction fragments: sticky ends that are made by restriction enzymes
4) Genomic library: a collection of all of the cloned DNA fragments from a target genome
5) Complementary DNA (cDNA): used to clone eukaryotic genes
6) Genetically modified (GM): organisms that contain one or more genes introduced by artificial means
7) Transgenic organisms: organisms that contain at least one gene from another species
8) DNA profiling: the analysis of DNA fragments to determine whether they come from a particular individual
9) Polymerase chain reaction (PCR): a method of amplifying a specific segment of a DNA molecule
10) Short tandem repeats (STRs): genetic markers used in DNA profiling

cloning.gif.png

This diagram shows how DNA cloning is happening. First, cells from the original sheep are taken. Second, unfertilized egg cell is taken and its nucleus gets removed. The nucleus of cells from the original sheep are put into the unfertilized egg with no nucleus. After that, cells keep reproducing themselves until they make an identical sheep. 


This video explains how to clone genes.


5 FACTS:
1. Genes can be cloned in recombinant plasmids.
2. Reverse transcriptase can help make genes for cloning.
3. Nucleic acid probes identify clones carrying specific genes.
4. Recombinant cells and organisms can mass-produce gene products.
5. Gene therapy may someday help treat a variety of diseases.

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