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1 May 2018

Scientists have learned a lot about genes. It is the hope that one day scientists will be able to remove a gene that causes a defect and replace it with a "normal" gene. They can already do this for some genes. Would it not be great to remove the defective genes and cure diseases and disorders like Cystic Fibrosis, Down syndrome, and sickle-cell anemia? Some people also think that it would be great to determine the eye color, hair color, and other traits of their offspring. What should we control using our knowledge of genetics? Should we cure diseases? Is death not a natural process of life? Should we form "designer" babies? Make sure you use scientific terms from the chapters in your post.

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Collen VonLv2

3 May 2018

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On the Edge Selling Personalized Genetics

Several companies on the Internet sell genetic tests directly to consumers including 23andMe, Navigenics, decode Genetics, DNA Tribes, Genelex, ScientificMatch, Consumer Genetics, Salugen, DNAprint Genomics, Genova Diagnostics, Suracell, and many more. The companies ask customers to collect a sample of their genes with a cheek swab and send it to them for testing. Most test by putting the customerâs gene sample on a small flat âDNA microarray chipâ that already contains pieces of DNA matching known genes (or gene mutations). If one of the customerâs genes matches one of the pieces of DNA on the chip, it binds to the DNA fragment which creates a tiny fluorescent glow showing that the gene indicated by the DNA fragment is in the sample. A computer then analyzes the pattern of glowing spots on the chip and prints out a list of the genes (or gene mutations) in the customerâs sample. Scientists have discovered a few genes that are associated with specific diseases or personal characteristics. Studies found, for example, genes that are linked to cystic fibrosis, Tay Sachs disease, and Lou Gehrigâs disease, genes that increase the risk of certain breast, colon, and thyroid cancers, and genes associated with sensation seeking, eye color, obesity, and lactose intolerance. They also found that some genes are more often found in people whose ancestors came from certain regions of the world. The companies say that based on these studies and their own gene tests, they can give customers valuable personalized information (for a price, of course). One company, Sciona, (no longer operating) said on its website: âSciona is a leader in nutrigenomics, the science of personalizing your nutrition and lifestyle choices to match your genesâ; Sciona gave customers âa personalized preventative dietary regimeâ that was supposed to prevent the diseases their genes put them at risk for. Another site promises: âBased upon the . . . [genetic] analysis, Suracell recommends to each client a personalized regimen of nutraceuticals [vitamin supplements].â Another states: âDNA Tribes . . . uses genetic material . . . to measure your genetic connections to individual ethnic groups and major world regions.â Another company claims to do it all: âWith a simple saliva sample weâll help you gain insight into your traits, from baldness to muscle performance. Discover risk factors for 95 diseases. Know your predicted response to drugs, from blood thinners to coffee. And uncover your ancestral origins.â Critics claim, however, that with a few exceptions, most studies have shown only weak connections between genes and specific traits, disease risks, drug responses, nutritional or vitamin needs, or ancestral origins. Many studies that link specific genes to a disease are only preliminary and the full picture has not yet been worked out. Moreover, critics say, it is wrong to tell customers their genes put them at risk of a deadly disease without proper counseling, especially when the scientific studies are weak and many other environmental, demographic, and lifestyle factors determine the actual onset of a disease. Ordinary consumers, they conclude, are being sold a product that they do not have the expertise to interpret. But defenders of the tests say consumers have a right to know what genes they carry and what science has learned about those genes. The companies charge from $140 to test for two or three genes, up to $999 to test for a full suite of genes. Evaluate the ethics of selling gene tests directly to consumers like these companies are doing. What would each of the three theories of a businessâs duties to consumers say about what the companies are doing? Under what conditions do you think selling the tests would be ethically legitimate? Check out the video of GAO interviews of gene-test company salespeople at http://www.gao.gov/products/gao-10-847t .

Based on this issue evaluate the ethics of selling gene tests directly to consumers. Watch the video showing GAO interviews of the gene-test company salespeople and evaluate the ethics of the selling practices shown on the video. Answer the following questions:

1. What would the three theories of business's duties to consumers say about what the companies are doing?

2. Is it ever ethical for direct-to-consumer selling of these tests?

3. Should the government-on its own discretion-be able to use the DNA data in the databases to solve crimes and catch criminals?

http://www.gao.gov/products/GAO-10-847T

2.Conclusion:

What have you learned from your study?

Interpret your data/ results:

Do your results support of disprove your hypothesis?

Compare and contrast your result with those of previous research.

Significance of the results: âBig Pictureâ

What is the global impact of your results?

What questions remain unanswered?

What kinds of experiments can come out of your study?

i have lab for biology and i need help with the Lab Report

the lab name is Bacterial Transformation Lab

1. Introduction:

Introduce the background and the nature of the problem your experiment is investigating.

Summarize the current knowledge of your subject.

Use examples of other research that have examined the same or a similar topic as your experiments.

Ending your introduction:

State your hypothesis

State your predictions

Give a brief statement about how you tested your hypothesis.

please help me with it is important for my lab class tomorrow

that is the lab i put the info please help me for the intro and for number 2 please be clear please

i would be happy if you help me it is due tommorrow i realy need your help on the intro and number 2 please be clear and show clear work hope you do it because it is due tomorrow

Bacterial Transformation Lab

Genetic engineering is one of the newest applications of basic knowledge in biology. It involves the isolation of specific genes from one organism and the insertion of those genes into a second organism of the same, or even different, species. Remember that a gene is a piece of DNA which codes for a product, usually a protein, which gives an organism a particular trait. The development of these techniques has generated considerable excitement and answered many questions, but it has also raised questions. Many scientists and others see genetic engineering as offering opportunities to make life better, for example, by exploring how genes are regulated, by curing diseases of genetic origin, by adding desirable traits to agricultural crops such as the ability to fix nitrogen in corn and pest resistance in cotton, and by genetically altering bacteria with genes enabling them to digest oil spills.

For almost 100 years, it has been possible to isolate DNA from cells, but only in the last 40 years or so has its function been understood. Your textbook discusses the work of such investigators as Fred Griffith and Oswald Avery, who demonstrated that if DNA was isolated from a pneumonia-causing strain of bacteria and added to cultures of nonvirulent bacteria, the recipient cells were transformed into virulent types that caused pneumonia. These transformation experiments were the first to show that genes could be artificially transferred in the laboratory. Since the time of those experiments (Avery's work was done in the 1940s), our knowledge of gene structure, function and control has increased astronomically. The application of this knowledge has created the field of genetic engineering.

Modern genetic engineering techniques depend on three critical factors:

A suitable host organism in which to insert the foreign gene;

A vector to carry foreign genes into the host; and

A means of isolating the host cells that have taken up the foreign gene.

The host organism

The most commonly used host organism is the gut bacterium Escherichia coli (E. coli). Its chromosome is a single large circular DNA molecule, called the genomic DNA, containing about 4 x 10⁶ base pairs. Not every cell will take up foreign DNA when exposed to it, but E. coli grows rapidly, dividing in less than 20 minutes, so that a single cell can give rise to a billion genetically identical descendants in a matter of 10 hours. Thus, a few transformed cells can provide a large number of offspring within a day. The strain we are using is K-12.

The vector

A vector is a DNA molecule used as a vehicle to carry genes from one organism to another. This DNA molecule can be modified by gene-splicing techniques using restriction enzymes and ligases so that it carries the genes of interest (essentially a cut-and-paste operation). Sometimes viruses are used as vectors, but for E. coli, plasmids are often used. A plasmid is a small circular DNA molecule containing 1000 to 200,000 base pairs. Plasmids exist naturally in many strains of E. coli and other bacteria. Plasmids replicate as the cell grows, independent of replication of the genomic DNA. These plasmids are transmitted to each of the product cells during cell division. Plasmids carrying genetic information that is beneficial to the host cell are maintained in a given population by natural selection. Plasmids frequently carry genes that confer antibiotic resistance, an obvious benefit.

When E. coli cells are exposed to plasmids or any other foreign DNA, some of the cells, called competent cells, will take up the DNA. We can induce cells to become competent by treating them with divalent cations, such as Ca⁺⁺, followed by a brief exposure to high temperature, called a heat shock treatment. Exactly how this treatment causes cells to become competent is not understood, but it is described as making the membranes "leaky" so that large DNA molecules (like plasmids), which would not normally pass through the cell membrane, can enter the cell. This treatment does not make all cells competent, but it greatly increases the number of competent cells. Once in a cell, the plasmids replicate and are passed to the product cells during cell division.

The selective medium

The last requirement for genetic engineering is a means of isolating host cells that have taken up the gene of interest. The techniques used depend on the growth requirements of the host organism. For example, each species of bacteria has particular nutrient requirements. The composition of the growth medium (agar or broth) can be modified to allow growth of only certain bacteria -- for example, by adding or removing nutrients or other chemicals from the medium mixture. This modified medium is called a selective medium, because it selects for the growth of only some species. By introducing an antibiotic such as ampicillin into the medium in which the bacteria are grown, you will select for growth of only those bacteria carrying the antibiotic-resistance gene on newly acquired plasmids. In a matter of days, billions of antibiotic-resistant cells, all with the plasmid, can be grown.

Genetic engineers use a modification of this technique to insert a foreign gene into E. coli. In simplified terms, the plasmid (already carrying an ampicillin resistance gene) is modified by inserting the gene of interest. The gene of interest has been isolated from another source; for example, the gene for human insulin has been isolated from the human genome. The modified plasmid, carrying the inserted gene, is then mixed with competent E. coli and the bacteria are placed in a medium containing ampicillin. Only those cells that have the plasmid will grow in the medium, and they are also the cells carrying the insulin gene (in their plasmids). These selected cells can now be used to manufacture insulin, which can be used for insulin therapy by diabetics.

The genes

In the following experiment, you will insert a plasmid into E. coli. The plasmid you will use carries the gene bla, which codes for a protein (beta-lactamase) that is secreted by the bacteria, inactivating the ampicillin in the agar and allowing for bacterial growth. The plasmid also carries an indicator gene. The indicator gene we are using was isolated from a bioluminescent jellyfish, Aequorea victoria. It codes for Green Fluorescent Protein (GFP).

The GFP gene has been modified to include a regulator system that can be used to control the expression of the gene. Gene expression in all organisms is carefully regulated to allow for adaptation to differing conditions and to prevent wasteful overproduction of unneeded proteins. The genes involved in the breakdown of different food sources are good examples of highly regulated genes. For example, the sugar arabinose is both an energy source and a carbon source for bacteria. The bacterial genes that make digestive enzymes to break down arabinose for food are not expressed when arabinose is not in the environment. But, when arabinose is present, these genes are turned on. When the arabinose runs out, the genes are turned off.

Arabinose initiates transcription of these genes by promoting the binding of RNA polymerase. In the genetically engineered pGLO DNA, some of the genes involved in the breakdown of arabinose have been replaced by the jellyfish gene GFP. When bacteria with this plasmid are grown in the presence of arabinose, the GFP gene is turned on and the bacteria glow green in UV light. When arabinose is absent form the growth medium, the GFP gene remains turned off and the colonies appear white. This is an example of the central molecular framework of biology in action: DNA ? RNA ? protein ? trait.

In summary, you will render E. coli cells competent to take up plasmid DNA. The plasmid carries two identifiable phenotypic markers:

The beta-lactamase or bla gene codes for resistance to the antibiotic ampicillin. We will use this to select for bacteria that have taken up the plasmid.

The pGLO gene codes for Green Fluorescent Protein (GFP), which is switched âONâ if arabinose is present.

Safety Procedure

For your own safety and the safety of others, it is essential that you follow all instructions about handling bacteria and disposal of materials. When you finish work for the day, swab your table with disinfectant. WASH YOUR HANDS thoroughly with soap before leaving the lab for any reason, and at the end of the day after you have cleaned your table. Report any spills to your instructor.

List of Materials

Prepared agar plates (2 LB, 2 LB/amp, 1 LB/amp/ara)

Transformation solution (50 mM CaCl₂, pH 7.4)

LB broth

1 pack of inoculation loops

Sterile transfer pipets

1 foam microtube holder w/ tubes

E. coli starter plate

1 red biohazard bag for loop disposal (common use â Loops/pipets only - NO PAPER!!!)