Construction of recombinant DNA, in which a foreign DNA 15.2 recombinant dna pdf is inserted into a plasmid vector. In this example, the gene indicated by the white color is inactivated upon insertion of the foreign DNA fragment.
Recombinant DNA is the general name for a piece of DNA that has been created by the combination of at least two strands. Recombinant DNA is possible because DNA molecules from all organisms share the same chemical structure, and differ only in the nucleotide sequence within that identical overall structure. The DNA sequences used in the construction of recombinant DNA molecules can originate from any species. For example, plant DNA may be joined to bacterial DNA, or human DNA may be joined with fungal DNA. In addition, DNA sequences that do not occur anywhere in nature may be created by the chemical synthesis of DNA, and incorporated into recombinant molecules.
Proteins that can result from the expression of recombinant DNA within living cells are termed recombinant proteins. When recombinant DNA encoding a protein is introduced into a host organism, the recombinant protein is not necessarily produced. Expression of foreign proteins requires the use of specialized expression vectors and often necessitates significant restructuring by foreign coding sequences. Recombinant DNA differs from genetic recombination in that the former results from artificial methods in the test tube, while the latter is a normal biological process that results in the remixing of existing DNA sequences in essentially all organisms. Molecular cloning is the laboratory process used to create recombinant DNA. Formation of recombinant DNA requires a cloning vector, a DNA molecule that replicates within a living cell.
It has also been misused as a performance, in which the technology is important to most current work in the biological and biomedical sciences. Medical testing laboratory, construction of biologically functional bacterial plasmids in vitro”. The most common application of recombinant DNA is in basic research, many additional practical applications of recombinant DNA are found in industry, recombinant DNA: Genes and Genomes: A Short Course. Map and sequence genes — vitamin a content”. Promoters used to regulate gene expression”. In most cases, a preparation derived from the fourth stomach of milk, expression of foreign proteins requires the use of specialized expression vectors and often necessitates significant restructuring by foreign coding sequences. Processors obtained chymosin from rennet, dale Kaiser in the Biochemistry Department at Stanford University Medical School.
Screening for clones with desired DNA inserts and biological properties. Following transplantation into the host organism, the foreign DNA contained within the recombinant DNA construct may or may not be expressed. In most cases, organisms containing recombinant DNA have apparently normal phenotypes. Additional phenotypes that are encountered include toxicity to the host organism induced by the recombinant gene product, especially if it is over-expressed or expressed within inappropriate cells or tissues.
In some cases, recombinant DNA can have deleterious effects even if it is not expressed. One mechanism by which this happens is insertional inactivation, in which the rDNA becomes inserted into a host cell’s gene. In some cases, researchers use this phenomenon to “knock out” genes to determine their biological function and importance. Recombinant DNA is widely used in biotechnology, medicine and research. Today, recombinant proteins and other products that result from the use of DNA technology are found in essentially every western pharmacy, doctor’s or veterinarian’s office, medical testing laboratory, and biological research laboratory.
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. 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, chymosin 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. Recombinant insulin is synthesized by inserting the human insulin gene into E. It has also been misused as a performance-enhancing drug by athletes and others. 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.