Emerge of recombinant DNA technology provided

- Pesticides can be held within the soil for many years after it has been sprayed, effecting the growth and development of crops. Transgenic methods for altering crops allow the soil to stay cleaner, allowing the plants that grow there to be healthier. The safer method would be the transgenic method as far as soil is concerned.

DNA, Deoxyribonucleic Acid, is the basic structure for all life, it is the blueprint, the instruction manual, on how to build a living organism. DNA is made up of four nitrogen bases, adenine, thymine, cytosine, and guanine which are connected by sugar-phosphate bonds. Through a process called Protein Synthesis, the nitrogen bases are the code for the creation of amino acids. Essentially, DNA makes amino acids, amino acids make proteins, proteins make organisms. This process has been taking place for much longer than scientists have been able to document. Those scientists are called geneticists and their field is genetics.

This procedure has also been performed successfully in the lab with dicots, broadleaf plants, soybeans and tomatoes for many years. Through this procedure, the desired gene and marker is inserted into the tDNA of the plasmid. Tissues of the organism are then transferred to a medium containing an antibiotic or herbicide in order to tell if the organism has successfully taken up the desired gene because only the tissues expressing the marker will survive. These tissues are then grown under controlled environmental conditions in tissue cultures containing nutrients and hormones so that whole plants are grown. When plants are grown and have produced seed, an evaluation of the progeny is done making sure that the desired traits have been passed on (Understanding GMOs).

A specific example of genetic modification or the recombination of DNA is shown through the development of golden rice. The gene for the enzyme phytoene synthase is extracted from the daffodil plant. Phytoene synthase is needed for the synthesis of a colourless carotene. The gene for the enzyme carotene desaturase is extracted from the soil bacterium. Carotene desaturase is used to catalyse multiple steps in the synthesise of carotenoids. These steps require many enzymes in plants. The recombined plasmid is then inserted into agrobacterium, which is then mixed with rice and plant embryos. This example of genetic modification created

Transgenic species are produce by genetic engineering. Genetic engineering involves the process of taking samples of one species genes/DNA and transferring it into a new host cell, this cell containing the DNA will then grow into the new cell creating a transgenic species. DNA samples can also be inserted into the new species by acting as a virus or by using a micro-pipette injection. Transgenic species are mainly used in fruit and vegetables to prevent pests eating the food supply. Genetic engineering is also used for commercial purposes. One example of successful transgenic species is a strawberry plant with a salmon gene inserted into it, the salmon gene helps the strawberries grow in a colder environment. These crops are also known as GMO’s (genetically modified organisms).

Forward and reverse genetics are ways to determine what genes or proteins are made by mutating or editing specific genes or proteins. In forward genetics, there is a specific phenotype and the goal is to figure out what genes cause that phenotype. This can be done in many different ways. For example, there could be a plant that wasn’t growing its roots and to figure out why, we would need to find all genes involved in the growing of the plants roots. The plant would need to be treated with some sort of mutagen, such as X-rays, chemicals, and insertional mutagenesis. X-rays can cause rearrangement and lose of DNA. Chemicals can result in point mutations, nonsense mutations, and non-coding regions. Insertional mutagenesis could effect the splicing of introns or where certain proteins bind/don’t bind affecting how they are coded. Then the plant would mate with multiple wild type plants. Each offspring of this plant would have different mutations. The plant(s) would be tested for the phenotype of interest or in this case, the ones not growing roots. This could

This particular promoter is vital for the survival and success of the soybean, which is why it considered to be a dependable promoter not only for soybeans, but for other genetically modified crops such as maize and beans. Monsanto used β-glucuronidase (GUS) as a selectable marker, to be the vehicle to transport the promoter and insert the CP4 EPSPS through transcriptional replacement (Jefferson, 1987). The GUS gene served as evidence of transformation; the GUS enzyme converts 5-bromo-4-chloro-3-indolyl β-D-glucuronide into a blue precipitate (Agricultural Group of Monsanto Company, 1993). Soybeans that were not transgenic would not produce this blue color when exposed to the aforementioned substrate, indicating that transformation did not take

One of the main factors that has led me to question whether edible vaccines will be a success in the future is the public’s concern regarding transgene transmission to neighbouring crops or weed species by cross-pollination. This risk can be reduced by integrating the transgene into the chloroplast genome which is maternally inherited. Chloroplast transformation pollen will not have the gene present. I think that transformation of the plastid’s genome is vital to some key issues that occur when genes are inserted into the plant’s nuclear genome. Transgenic plants commonly suffer with the “position effect”, when foreign genes are placed into their nuclear genome, which is the change in gene expression due to its relocation within the genome

The production of Bt-corn occurs in five steps. The first step is removing the desired gene from the organism. This step is a highly restrictive step due to the inadequate amount of information known about certain genes needed to enhance the genetic makeup of plants (Romero 1). Two main functions involved in this step are restriction enzymes and DNA ligase (Romero 1). The DNA ligase puts the DNA fragments back together. The second step is cloning the desired gene. The gene now undergoes a

The genetic engineering of plants is looming as one of the greatest and most intractable challenges of the 21st Century. Genetically modified organisms (GMOs) have been with us for some forty years, yet they are difficult to understand. Despite the fact that much has been written about them, controversy still surrounds their production and consumption.

Genetically modified organisms genes are transferred is by using “infectious, tumor-forming bacterium such as agrobacterium. Genes with desired characteristics are cut out of the donor DNA and spliced into bacteria DNA using a special enzyme. The bacteria then infects plant cells and carry altered DNA into cell’s nuclei. The cells multiply, forming a tumor, or callus, which can grow into a mature plant” (Cunningham 2015).

Instead of transferring large blocks of genes from donor plant to recipient, small isolated blocks of genes are put into the plant chromosome through biolistics, vectors, or protoplast transformation (Horsch 1993). Biolistics is a technique that shoots the gene block into the potential host cell. In order for the process to succeed, the microscopic particles and DNA must enter the cell nuclei and combine with the plant chromosome. Biolistics is commonly used but has a slight failure risk since the breeder has little control over the destination of the gene block (Mooney & Bernardi 1990). Bacteria or viruses can also carry the gene blocks into a new cell. Common vectors in gene transfer between plants are Agrobacterium tumefaciens and Agrobacterium rhizogenes. In the soil, the bacteria will infect the plants with their own plasmid, transferring the desired gene that was placed in the bacteria's DNA. Vector gene transfer is a preferred method of transformation since this modification already occurs naturally in the environment (Rudolph & McIntire 1996). Last is protoplast transformation, which uses enzymes to dissolve the cellulose in the plant wall that leaves a protoplast. Once a specific gene block is added to the protoplast, the cell wall will re-grow into a transgenic plant.

Bt cotton is a transgenic variety of cotton which was produced by the agricultural biotechnology company Monsanto. It was developed in order to reduce the heavy usage of pesticides in crops. This cotton has been genetically modified to produce a natural insecticide, preventing pests from feeding on the plant by killing them. The gene coding for the toxin produced by the bacterium Bacillus thuringiensis has been isolated and inserted into the cotton plant using transcription vectors (biological matter used to transfer genetic material between organisms). Recombinant DNA technology is heavily involved in this process; in bacterium, and in this case, B.thuringiensis, isolation of the beneficial gene is achieved by utilising restriction enzymes. Restriction enzymes can be described as ‘DNA-cutting’ enzymes found in bacteria; they cut DNA at specific bases sequences (recognition sites). The restriction enzymes creates (in this case), sticky ends so the base sequence coding for the Bt toxin gene is now isolated from the bacterium. After this, the gene is inserted into a plasmid of E.coli in order to create many identical copies in a process called transformation. This process happens since the same restriction enzyme used to isolate the gene is used to cut the plasmid; this creates resultant fragments of plasmid and DNA with sticky ends. The enzyme DNA ligase join the fragments together as complementary ends are paired together in a process called ligation.

The coding region of the gene is usually fused to a promoter, most commonly used is the 35S promoter from cauliflower mosaic virus (CMV), in order to promote higher expression levels. (Snow et. al, 1997) The popular method for genetic engineering of crop plants is natural gene transfer via an Agrobacterium tumefaciens vector, a bacterium normally found in soils. The transfer-DNA (T-DNA) vector is made by inserting the desired gene fragment in between specific 25bp repeat domains in the bacterium. The vector is then inserted into the Agrobacterium and "the virulence gene products of Agrobacterium actively recognize, excise, transport, and integrate the T-DNA region into the host plant genomes." (Conner et. al, 1999) The amount of DNA transferred is only about 10kb and the nature of the gene is usually well understood. The expression of the gene introduced can also be controlled by adding additional sequences that might allow the gene to be constitutively expressed, expressed only in certain cell types, or expressed as a result of different environmental changes. This method of gene transfer, however, will only work for the natural host range of the bacterium and therefore other methods are used for additional crop plants. Such methods are uptake of naked DNA by electroporation or particle gun bombardment. The use of genetic markers, as mentioned previously, allows for the preferential growth of cultures that contain the new genetic

For gene engineering, transfer DNA (t-DNA) is eliminated from the plasmid of the bacteria and then substituted with the desired foreign gene. It is then transferred to a random site in the genome of the plant.