Application of recombinant DNA technology in biotechnology

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Ministry of education and science of the Republic of Kazakhstan

M. Auezov South-Kazakhstan State University

“Chemical Engineering and Biotechnology” higher school

“Biotechnology” chair

For students of speciality: - 5B070100 - "Biotechnology"

Theme:

Application of recombinant DNA technology in biotechnology

Mamitova A.Zh.

Shymkent, 2015



Composers: ХТ -12 - 5а Bigaraeva A., Amangeldieva D., Nuriddin A.

Methodical instruction was composed with requirement of Educational plan and Curriculum of discipline Preventive health biotechnology and include all nessesary information.

For students of speciality: - 5B070100 - "Biotechnology"

© South-Kazakhstan State University named AFTER M.O. Auezov, 2015.



Plan

Introduction

1. Main

1.1 Recombinant DNA and Biotechnology

1.2 How is Recombinant DNA made?

1.3 Why is rDNA important?

1.4 Applications of recombinant DNA technology

2. Problem for the case study

2.1 Test questions

2.2 Crossword

2.3 Glossary

Conclusion

References



Introduction

The Basics of Recombinant DNA

That's a very good question! rDNA stands for recombinant DNA. Before we get to the "r" part, we need to understand DNA. Those of you with a background in biology probably know about DNA, but a lot of ChemE's haven't seen DNA since high school biology. DNA is the keeper of the all the information needed to recreate an organism. All DNA is made up of a base consisting of sugar, phosphate and one nitrogen base. There are four nitrogen bases, adenine (A), thymine (T), guanine (G), and cytosine (C). The nitrogen bases are found in pairs, with A&T and G&C paired together. The sequence of the nitrogen bases can be arranged in an infinite ways, and their structure is known as the famous "double helix" which is shown in the image below. The sugar used in DNA is deoxyribose. The four nitrogen bases are the same for all organisms. The sequence and number of bases is what creates diversity. DNA does not actually make the organism, it only makes proteins. The DNA is transcribed into mRNA and mRNA is translated into protein, and the protein then forms the organism. By changing the DNA sequence, the way in which the protein is formed changes. This leads to either a different protein, or an inactive protein.

Figure 1. Double helix

Now that we know what DNA is, this is where the recombinant comes in. Recombinant DNA is the general name for taking a piece of one DNA, and combining it with another strand of DNA. Thus, the name recombinant! Recombinant DNA is also sometimes referred to as "chimera." By combining two or more different strands of DNA, scientists are able to create a new strand of DNA. The most common recombinant process involves combining the DNA of two different organisms.



1. Main

1.1 Recombinant DNA and Biotechnology

Biotechnology is an industrial process that uses the scientific research on DNA for practical benefits. Biotechnology is synonymous with genetic engineering because the genes of an organism are changed during the process and the DNA of the organism is recombined. Recombinant DNA and biotechnology can be used to form proteins not normally produced in a cell. In addition, bacteria that carry recombinant DNA can be released into the environment to increase the fertility of the soil, serve as an insecticide, or relieve pollution.

Tools of biotechnology. The basic process of recombinant DNA technology revolves around the activity of DNA in the synthesis of protein. By intervening in this process, scientists can change the nature of the DNA and of the gene make-up of an organism. By inserting genes into the genome of an organism, the scientist can induce the organism to produce a protein it does not normally produce.

The technology of recombinant DNA has been made possible in part by extensive research on microorganisms during the last century. One important microorganism in recombinant DNA research is Escherichia coli (E. coli). The biochemistry and genetics of E. coli are well known, and its DNA has been isolated and made to accept new genes. The DNA can then be forced into fresh cells of E. coli, and the bacteria will begin to produce the proteins specified by the foreign genes. Such altered bacteria are said to have been transformed.

Interest in recombinant DNA and biotechnology heightened considerably in the 1960s and 1970s with the discovery of restriction enzymes. These enzymes catalyze the opening of a DNA molecule at a “restricted” point, regardless of the DNA's source. Moreover, certain restriction enzymes leave dangling ends of DNA molecules at the point where the DNA is open. (The most commonly used restriction enzyme is named EcoRl.) Foreign DNA can then be combined with the carrier DNA at this point. An enzyme called DNA ligase is used to form a permanent link between the dangling ends of the DNA molecules at the point of union (Figure 1).

The genes used in DNA technology are commonly obtained from host cells or organisms called gene libraries. A gene library is a collection of cells identified as harboring a specific gene. For example, E. coli cells can be stored with the genes for human insulin in their chromosomes.

Pharmaceutical products. Gene defects in humans can lead to deficiencies in proteins such as insulin, human growth hormone, and Factor VIII. These protein deficiencies may lead to problems such as diabetes, dwarfism, and impaired blood clotting, respectively. Missing proteins can now be replaced by proteins manufactured through biotechnology. For insulin production, two protein chains are encoded by separate genes in plasmids inserted into bacteria. The protein chains are then chemically joined to form the final insulin product. Human growth hormone is also produced within bacteria, but special techniques are used because the bacteria do not usually produce human proteins. Therapeutic proteins produced by biotechnology include a clot-dissolving protein calledtissue plasminogen activator (TPA) and interferon. This antiviral protein is produced within E. coli cells. Interferon is currently used against certain types of cancers and for certain skin conditions.

Vaccines represent another application of recombinant DNA technology. For instance, the hepatitis B vaccine now in use is composed of viral protein manufactured by yeast cells, which have been recombined with viral genes. The vaccine is safe because it contains no viral particles. Experimental vaccines against AIDS are being produced in the same way.

Diagnostic testing. Recombinant DNA and biotechnology have opened a new era of diagnostic testing and have made detecting many genetic diseases possible. The basic tool of DNA analyses is a fragment of DNA called the DNA probe. A DNA probe is a relatively small, single-stranded fragment of DNA that recognizes and binds to a complementary section of DNA in a complex mixture of DNA molecules. The probe mingles with the mixture of DNA and unites with the target DNA much like a left hand unites with the right. Once the probe unites with its target, it emits a signal such as radioactivity to indicate that a reaction has occurred. To work effectively, a sufficiently large amount of target DNA must be available.

Figure 2. The production of a a recombined bacterium using a gene from a foreign donor and the synthesis of protein encoded by the recombinant DNA molecule

To increase the amount of available DNA, a process called the polymerase chain reaction (PCR) is used. In a highly automated machine, the target DNA is combined with enzymes, nucleotides, and a primer DNA. In geometric fashion, the enzymes synthesize copies of the target DNA, so that in a few hours billions of molecules of DNA exist where only a few were before.

Using DNA probes and PCR, scientists are now able to detect the DNA associated with HIV (and AIDS), Lyme disease, and genetic diseases such as cystic fibrosis, muscular dystrophy, Huntington's disease, and fragile X syndrome.

Gene therapy. Gene therapy is a recombinant DNA process in which cells are taken from the patient, altered by adding genes, and replaced in the patient, where the genes provide the genetic codes for proteins the patient is lacking.

In the early 1990s, gene therapy was used to correct a deficiency of the enzyme adenosine deaminase (ADA). Blood cells called lymphocytes were removed from the bone marrow of two children; then genes for ADA production were inserted into the cells using viruses as vectors. Finally, the cells were reinfused to the bodies of the two children. Once established in the bodies, the gene-altered cells began synthesizing the enzyme ADA and alleviated the deficiency.

Gene therapy has also been performed with patients with melanoma (a virulent skin cancer). In this case, lymphocytes that normally attack tumors are isolated in the patients and treated with genes for an anticancer protein called tumor necrosis factor.

The genealtered lymphocytes are then reinfused to the patients, where they produce the new protein which helps destroy cancer cells. Approximately 2000 single-gene defects are believed to exist, and patients with these defects may be candidates for gene therapy.

DNA fingerprinting. The use of DNA probes and the development of retrieval techniques have made it possible to match DNA molecules to one another for identification purposes. This process has been used in a forensic procedure called DNA fingerprinting.

The use of DNA fingerprinting depends upon the presence of repeating base sequences that exist in the human genome. The repeating sequences are called restriction fragment length polymorphisms (RFLPs). As the pattern of RFLPs is unique for every individual, it can be used as a molecular fingerprint. To perform DNA fingerprinting, DNA is obtained from an individual's blood cells, hair fibers, skin fragments, or other tissue. The DNA is extracted from the cells and digested with enzymes. The resulting fragments are separated by a process called electrophoresis. These separated DNA fragments are tested for characteristic RFLPs using DNA probes. A statistical evaluation enables the forensic pathologist to compare a suspect's DNA with the DNA recovered at a crime scene and to assert with a degree of certainty (usually 99 percent) that the suspect was at the crime scene.

DNA and agriculture. Although plants are more difficult to work with than bacteria, gene insertions can be made into single plant cells, and the cells can then be cultivated to form a mature plant. The major method for inserting genes is through the plasmids of a bacterium called Agrobacterium tumefactions. This bacterium invades plant cells, and its plasmids insert into plant chromosomes carrying the genes for tumor induction. Scientists remove the tumor-inducing genes and obtain a plasmid that unites with the plant cell without causing any harm.

Recombinant DNA and biotechnology have been used to increase the efficiency of plant growth by increasing the efficiency of the plant's ability to fix nitrogen. Scientists have obtained the genes for nitrogen fixation from bacteria and have incorporated those genes into plant cells. By obtaining nitrogen directly from the atmosphere, the plants can synthesize their own proteins without intervention of bacteria as normally needed.

DNA technology has also been used to increase plant resistance to disease. The genes for an insecticide have been obtained from the bacterium Bacillus thuringiensis and inserted into plants to allow them to resist caterpillars and other pests. In addition, plants have been reengineered to produce the capsid protein that encloses viruses. These proteins lend resistance to the plants against viral disease.

The human genome. One of the most ambitious scientific endeavors of the twentieth century was the effort to sequence the nitrogenous bases in the human genome. Begun in 1990 and completed in 2003, the effort encompassed 13 years of work at a cost of approximately $3 billion. Knowing the content of the human genome is helping researchers devise new diagnostics and treatments for genetic diseases and will also be of value to developmental biologists, evolutionary biologists, and comparative biologists.

In addition to learning the genome of humans, the project has also studied numerous bacteria. By 1995, the genomes of two bacteria had been completely deciphered (Haemophilus influenzae and Mycoplasma genitalium), and by 1996, the genome of the yeast Saccharomyces cerevisiae was known. The Human Genome Project is one of colossal magnitude that will have an impact on many branches of science for decades to come. The project remains the crowning achievement of DNA

1.2 How is Recombinant DNA made?

There are three different methods by which Recombinant DNA is made. They are transformation, Phage Introduction, and Non-Bacterial Transformation. Each are described separately below.

Transformation

The first step in transformation is to select a piece of DNA to be inserted into a vector. The second step is to cut that piece of DNA with a restriction enzyme and then ligate the DNA insert into the vector with DNA Ligase. The insert contains a selectable marker which allows for identification of recombinant molecules. An antibiotic marker is often used so a host cell without a vector dies when exposed to a certain antibiotic, and the host with the vector will live because it is resistant. The vector is inserted into a host cell, in a process called transformation. One example of a possible host cell is E. Coli. The host cells must be specially prepared to take up the foreign DNA. Selectable markers can be for antibiotic resistance, color changes, or any other characteristic which can distinguish transformed hosts from untransformed hosts. Different vectors have different properties to make them suitable to different applications. Some properties can include symmetrical cloning sites, size, and high copy number.

Non-Bacterial Transformation

This is a process very similar to Transformation, which was described above. The only difference between the two is non-bacterial does not use bacteria such as E. Coli for the host. In microinjection, the DNA is injected directly into the nucleus of the cell being transformed. In biolistics, the host cells are bombarded with high velocity microprojectiles, such as particles of gold or tungsten that have been coated with DNA.

Phage Introduction. Phage introduction is the process of transfection, which is equivalent to transformation, except a phage is used instead of bacteria. In vitro packagings of a vector is used. This uses lambda or MI3 phages to produce phage plaques which contain recombinants. The recombinants that are created can be identified by differences in the recombinants and non-recombinants using various selection methods.

How does rDNA work? Recombinant DNA works when the host cell expresses protein from the recombinant genes. A significant amount of recombinant protein will not be produced by the host unless expression factors are added. Protein expression depends upon the gene being surrounded by a collection of signals which provide instructions for the transcription and translation of the gene by the cell. These signals include the promoter, the ribosome binding site, and the terminator. Expression vectors, in which the foreign DNA is inserted, contain these signals. Signals are species specific. In the case of E. Coli, these signals must be E. Coli signals as E. Coli is unlikely to understand the signals of human promoters and terminators.

Problems are encountered if the gene contains introns or contains signals which act as terminators to a bacterial host. This results in premature termination, and the recombinant protein may not be processed correctly, be folded correctly, or may even be degraded.

Production of recombinant proteins in eukaryotic systems generally takes place in yeast and filamentous fungi. The use of animal cells is difficult due to the fact that many need a solid support surface, unlike bacteria, and have complex growth needs. However, some proteins are too complex to be produced in bacterium, so eukaryotic cells must be used.



1.3 Why is rDNA important?

Recombinant DNA has been gaining in importance over the last few years, and recombinant DNA will only become more important in the 21st century as genetic

diseases become more prevelant and agricultural area is reduced. Below are

some of the areas where Recombinant DNA will have an impact.

· Better Crops (drought & heat resistance)

· Recombinant Vaccines (ie. Hepatitis B)

· Prevention and cure of sickle cell anemia

· Prevention and cure of cystic fibrosis

· Production of clotting factors

· Production of insulin

· Production of recombinant pharmaceuticals

· Plants that produce their own insecticides

· Germ line and somatic gene therapy

1.4 Applications of recombinant DNA technology

Recombinant DNA is widely used in biotechnology, medicine and research. Today, recombinant proteins and other products that result from the use of rDNA technology are found in essentially every western pharmacy, doctor's or veterinarian's office, medical testing laboratory, and biological research laboratory. In addition, organisms that have been manipulated using recombinant DNA technology, as well as products derived from those organisms, have found their way into many farms, supermarkets, home medicine cabinets, and even pet shops, such as those that sell GloFish and other genetically modified animals.



Figure 3. A group of GloFish fluorescent fish

The most common application of recombinant DNA is in basic research, in which the technology is important to most current work in the biological and biomedical sciences. Recombinant DNA is used to identify, map and sequence genes, and to determine their function. rDNA probes are employed in analyzing gene expression within individual cells, and throughout the tissues of whole organisms. Recombinant proteins are widely used as reagents in laboratory experiments and to generate antibody probes for examining protein synthesis within cells and organisms.

Many additional practical applications of recombinant DNA are found in industry, food production, human and veterinary medicine, agriculture, and bioengineering. Some specific examples are identified below.

Recombinant chymosin

Found in rennet, is an enzyme required to manufacture cheese. It was the first genetically engineered food additive used commercially. Traditionally, processors obtained chymosin from rennet, a preparation derived from the fourth stomach of milk-fed calves. Scientists engineered a non-pathogenic strain (K-12) of E. coli bacteria for large-scale laboratory production of the enzyme. This microbiologically produced recombinant enzyme, identical structurally to the calf derived enzyme, costs less and is produced in abundant quantities. Today about 60% of U.S. hard cheese is made with genetically engineered chymosin. In 1990, FDA granted chymosin "generally-recognized-as-safe" (GRAS) status based on data showing that the enzyme was safe.

Recombinant human insulin

Almost completely replaced insulin obtained from animal sources (e.g. pigs and cattle) for the treatment of insulin-dependent diabetes. A variety of different recombinant insulin preparations are in widespread use. Recombinant insulin is synthesized by inserting the human insulin gene into E. coli, which then produces insulin for human use.

Recombinant human growth hormone (HGH, somatotropin)

Administered to patients whose pituitary glands generate insufficient quantities to support normal growth and development. Before recombinant HGH became available, HGH for therapeutic use was obtained from pituitary glands of cadavers. This unsafe practice led to some patients developing Creutzfeldt-Jakob disease. Recombinant HGH eliminated this problem, and is now used therapeutically. It has also been misused as a performance enhancing drug by athletes and others.

Drug Bank entry Recombinant blood clotting factor VIII

A blood-clotting protein that is administered to patients with forms of the bleeding disorder hemophilia, who are unable to produce factor VIII in quantities sufficient to support normal blood coagulation.^[16] Before the development of recombinant factor VIII, the protein was obtained by processing large quantities of human blood from multiple donors, which carried a very high risk of transmission of blood borne infectious diseases, for example HIV and hepatitis B. Drug Bank entry

Recombinant hepatitis B vaccine

Hepatitis B infection is controlled through the use of a recombinant hepatitis B vaccine, which contains a form of the hepatitis B virus surface antigen that is produced in yeast cells. The development of the recombinant subunit vaccine was an important and necessary development because hepatitis B virus, unlike other common viruses such as polio virus, cannot be grown in vitro. Vaccine information from Hepatitis B Foundation

Diagnosis of infection with HIV

Each of the three widely used methods for diagnosing HIV infection has been developed using recombinant DNA. The antibody test (ELISA or western blot) uses a recombinant HIV protein to test for the presence of antibodies that the body has produced in response to an HIV infection. The DNA test looks for the presence of HIV genetic material using reverse transcription polymerase chain reaction (RT-PCR). Development of the RT-PCR test was made possible by the molecular cloning and sequence analysis of HIV genomes. HIV testing page from US Centers for Disease Control (CDC)

Golden rice

A recombinant variety of rice that has been engineered to express the enzymes responsible for в-carotene biosynthesis. This variety of rice holds substantial promise for reducing the incidence of vitamin A deficiency in the world's population. Golden rice is not currently in use, pending the resolution of regulatory issues.

Herbicide-resistant crops

Commercial varieties of important agricultural crops (including soy, maize/corn, sorghum, canola, alfalfa and cotton) have been developed that incorporate a recombinant gene that results in resistance to the herbicide glyphosate (trade name Roundup), and simplifies weed control by glyphosate application. These crops are in common commercial use in several countries.

Insect-resistant crops

Bacillus thuringeiensis is a bacterium that naturally produces a protein (Bt toxin) with insecticidal properties. The bacterium has been applied to crops as an insect-control strategy for many years, and this practice has been widely adopted in agriculture and gardening. Recently, plants have been developed that express a recombinant form of the bacterial protein, which may effectively control some insect predators. Environmental issues associated with the use of these transgenic crops have not been fully resolved.

The following recombinant DNA techniques used in biotechnology, including:

o gene splicing using restriction enzymes and ligases to produce recombinant DNA

o polymerase chain reaction to amplify or modify DNA sequences

o use of DNA vectors and microinjection for carrying genes into nuclear DNA in the production of transgenic multicellular organisms

Gene splicing using restriction enzymes and ligases to produce recombinant DNA

· The gene for insulin production in humans can be pasted into the DNA of Escherichia coli, a bacterium that inhabits the human digestive tract. This is done by cutting the appropriate gene from human DNA and pasting, or splicing, it into plasmid DNA, a special kind of DNA that takes a circular form and can be used as a vehicle for this editing job.

· It is cut using a class of enzymes called restriction enzymes. There are well over a hundred restriction enzymes, each cutting in a very precise way a specific base sequence of the DNA molecule. With these scissors used singly or in various combinations, the segment of the human DNA molecule that specifies insulin production can be isolated.

· This segment is "glued" into place using an enzyme called DNA ligase. The result is an edited, or recombinant, DNA molecule. The bacterial cells divide very rapidly making billions of copies of themselves, and each bacterium carries in its DNA a faithful replica of the gene for insulin production. Each new E. coli cell has inherited the human insulin gene sentence.

Polymerase chain reaction to amplify or modify DNA sequences

· This is by far the most successful method of amplifying (making many copies of) DNA sequences.

· The process is done in a test tube: the DNA required is isolated, fragmented with restriction enzymes and separated by gel electrophoresis. The DNA fragments are denatured (ie, made single stranded) by heating to about 95 degrees C. These single stranded DNA are exposed to a solution containing a radioactive DNA “probe”. The probe consists of single stranded DNA or RNA, with a sequence chosen to base pair with the required DNA. With correct temperature of about 50 - 65 degrees C, salt and correct pH the probe will bind to its corresponding sequence of the target DNA and nowhere else.

· As the process proceeds the DNA doubles after each cycle. Following thirty such cycles a theoretical one billion copies of DNA can be produced.

· PCR had been used to indicate the presence of HIV infection and has been used to amplify degraded DNA for use in forensic science.

Use of DNA vectors and microinjection for carrying genes into nuclear DNA in the production of transgenic multicellular organisms

· Commonly used vectors (carriers) are viruses or plasmids. A viral vector is first modified so that it will not replicate or cause disease in the target cells of the host embryo. The gene of interest is incorporated into the viral genome (See gene splicing above) and the virus is then used to infect an early stage embryo or a pronuclear embryo. The viral vector binds uniformly to the embryonic cells and acts as a vehicle to allow transfer and integration of the transgene into the host genome. If a pronuclear embryo is used the new gene will be expressed in every cell. However if the virus infects a cell of an early stage embryo not all cells will contain the new gene.

· Retroviruses are commonly used as vectors because of their ability to infect host cells in this way.

· If a retrovirus isn't used, eg a plasmid or other virus is used it can be inserted into the cell using microinjection.

· An advantage to using viral vectors is that usually only a single copy of the transgene is integrated into the genome. If the viral transfection is applied to oocytes (eggs) prior to fertilization, then the new gene will be present in all cells of the resulting embryo as though it had been contributed by the mother.

· The major disadvantage of this system is the time and labour-intensive process to prepare the viral vector. There is also a remote possibility that the modified viral vector may revert to its original state or recombine with other pathogenic viruses. Microinjection doesn't always result in the gene being incorporated into a chromosome in a way that it can be expressed.

Process and analyses secondary information to identify that complementary DNA is produced by reverse transcribing RNA or the polymerase chain reaction

· Use the information that you gathered in the above dot point on polymerase chain reaction.

· Gather any other information you might want to add to the information you already have by looking in biology and biotechnology texts or journals.

· Process the information by extracting the parts that are relevant.

· Identify that complementary DNA is produced by reverse transcribing RNA.

biotechnology genetic pharmaceutical vaccine agriculture



2. Problem for the case study

2.1. Test questions

What does the future hold?

Now that we've figured out the basics behind what Recombinant DNA are, it's time to look at how Recombinant DNA will impact the future. Which industries and fields will be shaped by rDNA?

How will rDNA effect the health and lifestyles of RPI students in the next generation? Click over to our rDNA Impact Statement to find out the answer! Pop Quiz Time! To help you determine how well you know Recombinant DNA, we have generously decided to provide you with a basic quiz that even a senior ChemE should be able to do. Be sure and look over the additional information provided below, because these questions could be tricky! All the information needed to answer the questions can be found on this case study.

1. What does the rDNA stand for?

A) Recombinant

B) Recycle

C) Rad

D) Radioactive

2. Are there ethical issues concerning rDNA?

A) Yes

B) No

C) At one time. Yes. But they've all been solved

D) Ethical what?

3. Which nitrogen base pairing is correct?

A) Adenine / Guanine and Thymine / Cytosine

B) Adenine / Cytosine and Guanine / Thymine

C) Adenine / Adenine and Cytosine / Cytosine

D) Adenine / Thymine and Guanine / Cytosine

4. What are three methods for creating rDNA?

A) Translation, transformation, excitation

B) Transformation, expression, ligation

C) Transformation, Phage Introduction, Non-Bacterial Transformation

D) Transfection, Transformation, Translation

5. Foreign DNA is inserted into what?

A) Expression Vectors

B) Terminator

C) Ribosome Binding Site

D) Promotor

6. In microinjection, the DNA is injected directly into the of the cell being

A) transformed

B) Nucleus

C) Cell Wall

D) Cell Membrane

E) Endoplasmic Reticulum

7. In Transformation, the DNA is cut with?

A) Restriction Enzyme

B) DNA Ligase

C) Bacteria

D) Vectors

8. In phage introduction, what is produced to contain recombinants?

A) Expression vectors

B) Introns

C) Proteins

D) Phages

9. In biolistics, the host cells are bombarded with what?

A) Neutrons

B) high velocity microprojectiles

C) sahigh velocity projectiles

D) electrons

10. What sugar is used in DNA?

A) Dioxyribose

B) Sucrose

C) Fructose

D) Glucose

11. Recombinant DNA is presently used in biotechnology industry to ?

A) Increase fertilization

B) treat infectious disease

C) treat genetic disorders

D) decrease agricultural yields

2.2 Crossword

Horizontal

2. Transfer of genetic material from one organism to another resulting in recombinant DNA

3. One of the four nitrogen bases

5. What will produce the desired protein

6. Which technique would most likely be used to produce large numbers of genetically identical offspring from this new variety of plant

8. What does the r in rdna stand for

9. One of the three methods by which Recombinant dna is made

10. The sequence of the nitrogen bases can be arranged in an infinite ways, and their structure is known as

11. Combining two pieces of dna to create one molecule

13. The sugar used in dna is

Vertical

1. What is used to cut the dna

4. Use … like plasmids and viruses

7. One of the three methods by which Recombinant dna is made

12. One of the four nitrogen bases

Right answers:



2.3 Glossary

Recombinant technology - molecules are DNA molecules formed by laboratory methods of genetic recombination (such as molecular cloning) to bring together genetic material from multiple sources, creating sequences that would not otherwise be found in biological organisms.

Biotechnology - is the use of living systems and organisms to develop or make useful products, or "any technological application that uses biological systems, living organisms or derivatives thereof, to make or modify products or processes for specific use"

Medicine - (UK English ⁱ/?m?ds?n/, /?m?d?s?n/; US English ⁱ/?m?d?s?n/) is the science or practice of the diagnosis, treatment, and prevention of disease.The word medicine is derived from the Latin ars medicina, meaning the art of healing. Medicine encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness.

DNA - abbreviation of deoxyribonucleic acid, organic chemical of complex molecular structure that is found in all prokaryotic and eukaryotic cells and in many viruses. DNA codes genetic information for the transmission of inherited traits.

Gene - unit of hereditary information that occupies a fixed position (locus) on a chromosome. Genes achieve their effects by directing the synthesis of proteins.

Protein - highly complex substance that is present in all living organisms. Proteins are of great nutritional value and are directly involved in the chemical processes essential for life.

Plasmid - in microbiology, an extrachromosomal genetic element that occurs in many bacterial strains. Plasmids are circular deoxyribonucleic acid (DNA) molecules that replicate independently of the bacterial chromosome.

Bacteria - singular bacterium, any of a group of microscopic single-celled organisms that live in enormous numbers in almost every environment on Earth, from deep-sea vents to deep below Earth's surface to the digestive tracts of humans.

Cytoplasm - the semifluid substance of a cell that is external to the nuclear membrane and internal to the cellular membrane, sometimes described as the nonnuclear content of protoplasm.

Cell - in biology, the basic membrane-bound unit that contains the fundamental molecules of life and of which all living things are composed. A single cell is often a complete organism in itself, such as a bacterium or yeast.

Species - in biology, classification comprising related organisms that share common characteristics and are capable of interbreeding.

Virus - an infectious agent of small size and simple composition that can multiply only in living cells of animals, plants, or bacteria. The name is from a Latin word meaning “slimy liquid” or “poison.”

Nucleic acid - naturally occurring chemical compound that is capable of being broken down to yield phosphoric acid, sugars, and a mixture of organic bases (purines and pyrimidines).

RNA - abbreviation of ribonucleic acid, complex compound of high molecular weight that functions in cellular protein synthesis and replaces DNA (deoxyribonucleic acid) as a carrier of genetic codes in some viruses.



Conclusion

The idea of recombinant DNA was first proposed by Peter Lobban, a graduate student of Prof. Dale Kaiser in the Biochemistry Department at Stanford University Medical School. The first publications describing the successful production and intracellular replication of recombinant DNA appeared in 1972 and 1973. Stanford University applied for a US patent on recombinant DNA in 1974, listing the inventors as Stanley N. Cohen and Herbert W. Boyer; this patent was awarded in 1980. The first licensed drug generated using recombinant DNA technology was human insulin, developed by Genentech and Licensed by Eli Lilly and Company. Scientists associated with the initial development of recombinant DNA methods recognized that the potential existed for organisms containing recombinant DNA to have undesirable or dangerous properties. At the 1975 Asilomar Conference on Recombinant DNA, these concerns were discussed and a voluntary moratorium on recombinant DNA research was initiated for experiments that were considered particularly risky. This moratorium was widely observed until the National Institutes of Health (USA) developed and issued formal guidelines for rDNA work. Today, recombinant DNA molecules and recombinant proteins are usually not regarded as dangerous. However, concerns remain about some organisms that express recombinant DNA, particularly when they leave the laboratory and are introduced into the environment or food chain. These concerns are discussed in the articles on genetically modified organisms and genetically modified food controversies.

Recombinant DNA technology, joining together of DNA molecules from two different species that are inserted into a host organism to produce new genetic combinations that are of value to science, medicine, agriculture, and industry. Since the focus of all genetics is the gene, the fundamental goal of laboratory geneticists is to isolate, characterize, and manipulate genes. Although it is relatively easy to isolate a sample of DNA from a collection of cells, finding a specific gene within this DNA sample can be compared to finding a needle in a haystack. Consider the fact that each human cell contains approximately 2 metres (6 feet) of DNA. Therefore, a small tissue sample will contain many kilometres of DNA. However, recombinant DNA technology has made it possible to isolate one gene or any other segment of DNA, enabling researchers to determine its nucleotide sequence, study its transcripts, mutate it in highly specific ways, and reinsert the modified sequence into a living organism.



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