Question

Explain the use of genetic engineering techniques in analyzing or manipulation DNA

(for what are the following processes used)

Genetic engineering

Electrophoresis

Polymerase chain reaction

Bacterial transformation

DNA sequencing

Answer 1

1. Genetic engineering: Genetic engineering also called as DNA recombinant technology. This technology is used to form new heritable genetic material which involves cut off and join together genetic material (especially DNA) from different biological species and introduce a new hybrid DNA. Most typical manipulating DNA is done by isolating dna from cells, cleaving the dna using a specific enzyme called restriction endonuclease, mixing up of and join the two independent dna obtained from two different species using the enzyme DNA ligase and thus a hybrid dna is formed.

2. Electrophoresis: It is an electrokinetic process helps in separating charged particles relative to fluid under the influence of electric field. Electrophoresis of postively charged particels (cations) are called as cataphoresis and negatively cherged particles (anions) are called as anaphoresis. Electrophoresis consists of horizontal electrophoresis system (DNA and RNA analysis) and vertical electrophoresis system (Protein analysis).

Types of electrophoresis: 1. Agarose gel electrophoresis: Used for electrophoresis of DNA of large mocecular size.

2. Polyacrylamide gel electrophoresis (PAGE): Used to identify how protein binds to DNA . 3. 2D-electrophoresis helps in separating molecules along X-axis and Y-axis (separated by charge on one side and size on the other side).

3. Polymerase chain reaction: It is a technique rapidly used in molecular biology to make copies of specific DNA region of an organism. It is the fundamental test used in much of the genetic testing samples including ancient samples and to identify the causal organism. The polymerase chain reaction is carried out in thermal cycler which was invented in 1983 by an American Biochemist - Kary Banks Mullis, for which he was awarded Noble Prize in the same year. Applications of this technique: gene cloning and manipulation, DNA cloning for sequencing, gene mutation, amplification of anticancer DNA, analysis of genetic fingerprints for DNA profiling (forensic sciences), detection of pathogens in nucleic acids for the diagnosis of infectious diseases.

4. Bacterial transformation: It is a process of horizontal gene transfer by which some of the bacteria have the tendency to take up foreign genetic material from the environment. The process was first reported by Griffith in 1928 from Streptococcus pneumoniae. This is the key step in DNA cloning which occurs after restriction digest and ligation and thus tranfers newly formed plasmids to bacteria. Afer transformation, the bacteria are placed under antibiotic plates and the bacteria with antibiotic resistant will form colonies

5. DNA sequencing: It is a process of determining the nucleic acid sequence - the order of nucleotides (As, Ts, Cs and Gs) the building blocks called bases in a piece of DNA. In a DNA duble helix, the four neucleotides pairs as adenine always pairs with thymine with three bonds which is stable and cytosine pairs with cytosine with two bonds which is unstable. New sequencing tchnology involves DNA polymerase as copy DNA to make new copies in the cells. Another new technology is the use of nanopores to sequence DNA molecules.