Mikayla+Bossman

=== ﻿ DNA Cloning/Recombinant DNA/Genetic Engineering ===

__Gene Cloning with Bacterial Plasmids __
Description: Gene cloning with bacterial plasmids is a delicate procedure that would not be able to be done under the naked eye, since it deals with DNA. Scientists take a gene or a section of DNA they have interest in and insert it into a bacterial plasmid. This plasmid is then incorporated back into the bacterial cell. After it is in the cell, it can be multiplied and duplicated as many times as necessary or needed. Analysis: To begin, scientists retain a plasmid, and using restriction enzymes, they cut the plasmid into a complementary shape to the DNA of interest. Then, the DNA is cut in the same manner, to have the same shape. This DNA is incorporated into the plasmid. DNA ligase forms covalent bonds and now the DNA and plasmid are joined. Now the plasmid needs to be reincorporated into the bacterium. This is called transformation. Finally, the bacterium is placed in a growth medium, allowing the cells to replicating, which thus replicates the DNA. Application: To put them at the simplest, the application of this is one of two things: creating a protein product, or making copies of a gene. To go farther than that, though, it can be used for resistance to pesticides, or it can be used for means for creating a large quantity of hormones, such as a growth hormone. Thoughts on it: This technology is great, and I think that great things can come from it. Genes hold the secrets of life, of certain species abilities to do things others can't. I think that if this went far enough, this process could produce huge amounts of certain genes that possibly be applied to humans, for human modifications. The gene to develop night vision and the gene to be able to hear or smell exponentially better are at our fingertips. This technique enables scientists to create masses of these genes. If these genes could be incorporated into the human genome, it could change the world as we know it. Arguement: Arguing against this wouldn't make much sense because it is currently helping people and could help people in the future.

To learn more go to @http://www.ornl.gov/sci/techresources/Human_Genome/elsi/cloning.shtml



__ Nucleic Acid Hybridization __
Description: This is the process of distinguishing and screening the DNA of interest from other DNA by using the gene of interest's ability to bind to a complementary strand, called a nucleic probe. Analysis: Scientists want to find a certain gene in a large amount of DNA and bacterial colonies. Because DNA matches up to its complementary strand, the scientists synthesize a DNA fragment with the complementary nucleic acid sequence, and make it radioactive. Then the strand finds its complement and the gene o﻿f interest is found. Application: T﻿his technology is used to find genes of interest. Thoughts on it: This technique could be used for a great many things. Because it locates certain genes, it might be possible to figure out a way to 'cure' some genetic problems, or at leas﻿t tell scientists or genetists whether or not a person has the gene for something. Arguement: ﻿I think that this is a beneficial thing. One disadvantage, though, is that one needs to know a section of the code to be able to locate it.

To learn more go to: []

__ Genomic Library [[image:http://www.fao.org/docrep/004/t0094e/T0094E37.gif width="348" height="394" align="right"]] __
Description: A genomic library is the complete set of plasmid-containing cell colonies, each carrying copies of a particular segment from the initial genome. A few different vectors are used in a genomic library. One is a bacterialphage. This is beneficial because it can hold more base pairs than a plasmid - twice as many. Another type is a bacterial artificial chromosome, also known as a BAC. These are large plasmids that contain just the genes necessary to ensure replication and can carry inserts of 100 - 300 kb. Analysis: A genomic library can be made of a couple things. The vectors that the genes of interest go into can be different, the storage containers that these are put into also varies. Application: This technology is used for storage a genome, most likely for future use. Thoughts on it: The whole idea of a genomic library is fascinating - to think of all DNA to be in one place, and for the most part, organized. If, in the future, we could have all DNA 'unraveled,' this could be put into a genomic library, providing information and seeing how different species might be related through their genes and like genomes. I think that would be very interesting. Arguement: This is an amazing idea, and amazing technology, but it does have some disadvantages. It seems a bit unorganized, and the ability of the scientists to find what gene they need is a bit blurred. The positive, though, is that it is most likely better than extracting the DNA everytime you might be wondering about it.

To learn more go to: []

__ Polymerase Chain Reaction __
Description: The process of Polymerase Chain Reaction, or PCR, can copy any specific targeted DNA segment. This is helpful because a whole cell does not need to replicate, only the gene does. An example of this would be like in a library, instead of checking out all the books, it just makes a copy of one page instead. Analysis: In PCR, it takes three steps to multiple the DNA. First, it is heated to denature the DNA strands. Then it is cooled so it forms hydrogen bonds with short DNA promers that are single-stranded. Lastly, a heat-stable DNA polymerase extends the primer towards the 3' end of the strand. Only small amounts of DNA are needed. Application: This technique is used for amplifying the amount of one or more DNA molecules quickly. Thoughts on it: I think that this technology could have the same uses that gene cloning with bacterial plasmids could. Arguement: An advantage would be that it can multiply DNA fast and have specifity. A disadvantage is that it cannot substitue gene cloning in cells when large amounts of a gene are desired. Also, errors occur, which limits the amount of good copies that can be used.

To learn more go to: []

__ ﻿Gel Electrophoresis [[image:http://www.biologyreference.com/images/biol_02_img0140.jpg width="223" height="228" align="right"]] __
__ ﻿ __ Description: Gel electrophoresis is a method for studying DNA molecules. DNA is put into gel which acts as a sieve to sort nucleic acids or proteins because of their size, electrical charge, and other properties. It separates on the basis of their rate of movement through the gel in an electric field. The distance the molecule travels is related to the size, but opposite. Analysis: A mixture of DNA molecules are placed in a well at one end of a thin slab of gel. The tray has electrodes at each end. When the electrodes are turned on and produce a current, the negatively charged DNA molecules move through the gel toward the positive end. The shorter molecules can travel farther than the larger, longer molecules, so they form different bands. Application: This has many uses and in many fields. It is used in forsensics, to match DNA, or do paternity tests. Also, it show genetic diseases. Thoughts on it: This process already has many uses, the only thing I can think of is to improve this to make it easier. Arguement: This has helped many people and in many different fields.

To learn more go to: []



__ Southern Blotting __
Description: Southern Blotting is the combination of gel electrophoresis and nucleic acid hybridization. Analysis: The DNA sample is mixed with a restriction enzyme and that results in many short restriction fragments. Then the restriction fragments are seperated by gel electrophoresis, forming bands of different lengths. Then the DNA are denatured and transferred onto a membrane. To link the DNA to the membrane, it is treated with UV rays. Then a radioactive probe is incubated with a membrane (just like nucleic acid hybridization), and this shows the genes of interest. Application: It has been used to identify mutant alleles associated with genetic diseases. Also, it can be used to tell if the bacteria has accepted the DNA and/or for matching DNA for forensics. Thoughts on it: Southern blotting is very similar to gel electrophoresis and nucleic acid hybridization, so it has the same potential as each of them. These processes can help society with what they could provide in the future. Arguement: It has helped people, and eliminated diseases, so it is a good thing.

To learn more go to: []



__ ﻿Microarrays __
__ ﻿ __ Description: Microarrays help with genome-wide studies. Each microarray contains many different short segments of DNA, representing different genes. These are fixed onto a glass plate or slide. From the results of the tests, scientists can figure out which genes are expressed of the millions of genes by measuring the amount of mRNA bound to each site. Analysis: A robot dips a set of pins into tiny wells filled with the strands of DNA material. Then the robot carries the pins to the glass slides and deposits it. (The DNA on the slide is known as a DNA slip.) The robot brings the DNA slip to the second set of wells where they are dipped in microscopic vats of DNA. At this point the chips are examined. Application: Microarrays are useful because they require only a small number of genes, they allow us to study large numbers of genes quickly, and they make it easy to compare gene expression from two different cells types. Thoughts on it: This seems awesome, but it seems just like genomic library. Arguement: This seems to help people, so it's good.

To learn more go to: []

__ ﻿ __
Description: Plant cloning is commonly used today in agriculture. It has also been naturally occurring for many years. A plant can spread and clone itself by sending out a 'runner'. This occurs in strawberries, potatoes, grasses, and onions. Also, people have been cloning vegetables for a long time by vegetable propagation. Growing a leaf from one plant into another is cloning because these new samples have the same genetic make up as the original plant. Analysis: This is relatively simple and many people can do it themselves. Just take a chunk of one plant, plant it and it clones itself by growing. Application: This is widely used in agriculture today to grow prize crops. Thoughts on it: I think that this has far to go, and could help solve some of the food problems. Possibly solve world hunger? Wouldn't that be great? Arguement: This is a positive thing, because it has the potential to help many people.

To learn more go to: []

__ Animal Cloning __
Description: Animal cloning is when a single cell is taken from a parent organism and made to create a genetically identical organism. The first part of cloning will be done in vitro (in a petri dish) and the second part will be done in vivo (reimplanting into a surrogate). Analysis: The first process of animal cloning used embryonic cells. Scientists would remove the DNA from an embryonic cell. They would then put this DNA in an egg cell. The egg cell would have had its nucleus removed. Using shock therapy or a specific mixture of chemicals scientists would stimulate fertilization. After fertilization scientists would implant the cell into a surrogate mother. This process worked but the animals would only live for a very short time and they would never fully mature. The process scientists now use to clone animals uses somatic cells. A somatic cell is any cell that isn't a reproductive cell. First scientists remove the somatic cell normally through a biopsy. Then they get an egg cell and remove the nucleus. Once the nucleus is removed the DNA from the somatic cell will be put into the egg cell. This process is known as somatic cell nuclear transfer (SCNT). Once scientists have the somatic cell DNA in the egg cell they will fuse the two together with electricity. This will stimulate the egg. The egg will then divide like it would if it had been fertilized the traditional way. At this point they would place the egg in a culture medium where a blastocyst forms. Scientists then insert this blastocyst into a surrogate mother. At this point the pregnancy carries out as if it was a normal pregnancy. The surrogate mother will carry the cloned baby to full term. Another process called genetic twinning can also occur. In genetic twinning they take a fertilized embryo out of a mother and physically separate the cell before sticking it back into the mother. Ap﻿plication: This can help with improving herds in farming, medicinal purposes, and studying diseases. Thoughts on it: This technology can improve society, but ethical issues also come in to play. So it might be a while before we see any developments on this topic. Arguement: This has created some discussions of ethics, but I think, for the most part, it is a positive thing as long as it isn't used for human cloning for huge armies or something crazy and insane like that.

To learn more go to: []

__ Restriction Fragment Length Polymorphism (RFLPs) [[image:http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/R/RFLPs_8.gif width="377" height="262" align="right"]] __
Description: RFLPs is a sequence change. The change is altered because of SNPs. Analysis:RFLPs are alterations that change the lengths of restriction fragments formed by digestion with an enzyme. RFLPs can be found on the introns or exons of DNA. RFLPs can be used as genetic markers because Southern blotting can be used to detect them. Application: Genetic diseases can be found using this method. Thoughts on it: RFLPs seem very useful in studying genetics, and seeing how some genes are passed from parent to child. Arguement: This seems helpful in finding diseases, as it is the way Huntington's disease was found.

To learn more go to: []

__ Gene Therapy [[image:http://library.thinkquest.org/28000/media/genetherapy/l_gene.therapy-ms.gif width="307" height="228" align="right"]] __
Description: Gene therapy is a technique for correcting diseases. A normal gene may be inserted into a nonspecific location within the genome to replace a nonfunctional gene. An abnormal gene could be swapped for a normal gene through homologous recombination. The abnormal gene could be repaired through selective reverse mutation, which returns the gene to its normal function. The regulation (the degree to which a gene is turned on or off) of a particular gene could be altered. Analysis: First, a "normal" gene is inserted into the genome to replace an "abnormal," disease-causing gene. Target cells are infected with the viral vector. The vector then unloads its genetic material containing the therapeutic human gene into the target cell. Then functional proteins return the target cell to its normal state. Application: Used to treat or prevent diseases. Thoughts on it: This has a lot of potential, because this ultimately could change the way humans look, through gene therapy. Arguement: This also could have ethnic issues because of what might be changed and what genes might be manipulated through this, but it also could help a lot of people with diseases.

To learn more go to: []

__ Transgenic animals __
description: A transgenic animal has foreign genes inserted into its genome. analysis: First they remove eggs from a female of the recipient species and fertilize them in vitro. Also, they clone the gene of interest from the donor organism. Then they inject the cloned DNA directly into the nuclei of the fertilized eggs. Some integrate the DNA and express the gene. These are then surgically implanted into the surrogate mother. If the embryo develops, it is a transgenic animal. Application: The transgenic animal can act as pharmaceutical factories and develop proteins for medicinal uses. Thoughts on it: This could develop into maybe a way to develop new limbs or organs. That would help with waiting lists in hospitals for organs. Arguement: On this one, I can't say that developing drugs and proteins this way sounds natural. I think that the organ idea is good, and could help many people, but I'm not sure how much I agree with the production of drugs this way.

To learn more go to: []

__ Transgenic plants [[image:http://www.isb.vt.edu/news/images/jun0701-3.jpg width="340" height="354" align="right"]] __
Description: Making transgenic plants can happen two ways. It can either be done the same way as a transgenic animal with a vector, as described above, but it can also be produced by shooting microscopic pellets containing the gene directly into the cell.

Analysis:The Ti plasmid is isolated from the bacterium. The segment of the plasmid that integrates into the genome of the host cells is called T DNA. The foreign gene of interest is inserted inot the middle of the T DNA. Recombinant plasmids can be introduced into cultured plant cells by electroporation. Once a plasmid is taken inot a plant cell its T DNA integrates into the cell's chromosomal DNA. Application: This can result in better nutritional quality, insect resistance, and/or disease resistance. Thoughts on it: I think that a lot can happen with the nutritional quality of plants, with vegetables and fruits, making them nutrient dense. Arguement: This is a positive thing, it could help with nutrition and health of people.

To learn more go to: []

Genetic Profiles Description: A genetic profile is basically a person's genome. It provides identification of certain people, mostly used in forensics. Analysis: DNA profiling uses repetitive sequences that are highly variable. A sample of DNA is needed to make a genetic profile. Application: This is used for matching DNA at scenes, and also paternal tests. Thoughts on it: this could be developed even more to solve crimes. Arguement: This is definitely a positive thing, it helps society as a whole by catching criminals.

To learn more go to: []

Sources: Campbell Reece eighth edition biology book the 'learn more' sites listed above.