Biology, asked by kumarsjtd, 1 year ago

write about the process of recombinant DNA technology

Answers

Answered by Tejaswini415
1
Recombinant DNA is the technology used for making artificial DNA (genetic modification) by combining different genetic materials (DNA) from different sources. It is the laboratory methods of genetic recombination to get genetic material (DNA) from different sources which would create a genomic sequence that would not otherwise be found in the genome.  

Molecular Scissors (Restriction Endonucleases):

Using of Molecular Scissors is the second step in making recombinant DNA. Molecular Scissors also known as Restriction Endonuclease is the enzyme which cleaves DNA molecules at specific base sequences producing small gene fragments by breaking internal covalent bonds linking nucleotides, used in recombinant DNA technology and chromosome mapping. They are natural enzymes of bacteria, which they use for their own protection against viruses. The restriction enzyme (Restriction Endonuclease) cuts down the viral DNA, but does no harm to the bacterial chromosome. They are called restriction enzymes ormolecular scissors because they restrict the growth of viruses. In 1970, Hamilton D. Smith, at Johns Hopkins University, isolated the first restriction enzyme. 

Palindromic Sequences:



A palindromic sequence is the nucleic acid sequence (DNA or RNA) which reads the same in both directions. These sequences are recognition sites for enzymes. Bacteria produce a variety of such restriction enzymes, which cut the DNA at very specific sites characterized by specific sequence of four to six nucleotides arranged symmetrically in the reverse order. Such sequences are known as palindromic sequences. So far more than 400 such enzymes have been isolated out of which about 20 are frequently used in recombinant DNA technology.

EcoR1 (A Restriction Enzyme): EcoR1, a commonly used restriction enzyme (endonuclease), cuts double stranded DNA when it has this sequence of bases at the cleavage site. Notice there is now a gap into which a piece of foreign DNA can be placed, if it ends in bases complementary to those exposed by restriction enzyme.

Recombinant DNA Preparation:

For preparation of recombinant DNA, the plasmids are cut with the same molecular scissors (restriction enzymes), which was used for isolation of the gene. The gene of interest for instance insulin is then joined with the sticky ends produced after cutting the plasmids with the help of another special enzyme called DNA ligase. DNA ligase is a very important enzyme in recombinant DNA technique that facilitates the joining of DNA strands together by catalyzing the formation of a phosphodiester bond. It seals the foreign piece of DNA into vector. Now the two different pieces of DNA have joined together which is now known asRecombinant DNA or Chimaeric DNA.

Expression of Recombinant DNA:

A clone can be a large number of molecules (i.e. cloned genes) or cells (i.e. cloned bacteria) or organisms that are identical to an original specimen. Bacterial cells take uprecombinant plasmid, especially if they are treated with calcium chloride to make them more permeable. Thereafter, as the cell reproduces, a bacterial clone forms and each new cell contains at least one plasmid. Therefore, each of the bacteria contains the gene of interest, which will express itself and make a product. From this bacterial clone, the cloned gene can be isolated for further analysis or protein product can be separated. Besides plasmids, the DNA of bacterial viruses (for example lambda phage) can also be used as a vector. After lambda phage it attaches to a host bacterium, recombinant DNA is released from the virus and enters the bacterium. Here it will direct the reproduction of many more viruses. Each virus in bacteriophage clone contains a copy of the gene being cloned.
hope this answer is useful to u if helps plz mark it as brain list

Tejaswini415: plz mark it as brain list friend
Similar questions