8-4-1-recombinant-dna-technology

Recombinant DNA Technology

Recombinant DNA

• The genetic code is universal, meaning that almost every organism uses the same four nitrogenous bases – A, T, C & G

• The genetic code is the basis for storing instructions that, alongside environmental influences, dictate the behaviour of cells and, as a result, the behaviour of the whole organism

• The universal nature of the genetic code means that the same codons code for the same amino acids in all living things

  • This means that genetic information is transferable between species

• Thus, scientists have been able to artificially change an organism’s DNA by combining lengths of nucleotides from different sources (typically, the nucleotides are from different species)

• The altered DNA, with the introduced nucleotides, is called recombinant DNA (rDNA)

• If an organism contains nucleotide sequences from a different species, it is called a transgenic organism

• Any organism that has introduced genetic material is a genetically modified organism (GMO)

• The mechanisms of transcription and translation are also universal, which means that the transferred DNA can be translated within cells of the genetically modified organism

Recombinant DNA technology

• This form of genetic engineering involves the transfer of fragments of DNA from one organism/species into another organism/species

• The resulting genetically engineered organism will then contain recombinant DNA and will be a genetically modified organism (GMO)

• For an organism to be genetically engineered, the following steps must be taken:

  • Identification of the DNA fragment or gene

  • Isolation of the desired DNA fragment

  • Multiplication of the DNA fragment (using polymerase chain reaction)

  • Transfer into the organism using a vector (e.g. plasmids, viruses, liposomes)

  • Identification of the cells with the new DNA fragment (by using a marker), which is then cloned

• Genetic engineers need the following to modify an organism:

  • Enzymes (restriction endonucleases, ligase, and reverse transcriptase)

  • Vectors – used to deliver DNA fragments into a cell (e.g. plasmids, viruses and liposomes)

  • Markers – genes that code for identifiable substances that can be tracked (e.g. GFP – green fluorescent protein, which fluoresces under UV light, or GUS – β-glucuronidase enzyme, which transforms colourless or non-fluorescent substrates into products that are coloured or fluorescent)

• Genetic engineering is being used in the new field of science called synthetic biology

  • This is an area of research that studies the design and construction of different biological pathways, organisms and devices, as well as the redesigning of existing natural biological systems