By isolating the antibiotic resistance gene by cutting out a piece of DNA  from a plasmid which was responsible for conferring antibiotic resistance .Please explain this clearly 

Asked by valavanvino1011 | 18th Jul, 2019, 08:21: PM

Expert Answer:

  • Some genes called selectable markers help in selecting those host cells which contain the transformed vectors and eliminate the non-transformants.
  • Transformation is a process through which a piece of DNA is introduced in a host bacterium.
  • Generally, the genes encoding resistance to antibiotics such as tetracycline, ampicillin and kanamycin are useful selectable markers for E. coli.
  • Plasmid pBR322 has two resistance genes—ampicillin resistance (ampR) and tetracycline resistance (tetR)—which are considered useful for selectable markers.
  • If a recombinant DNA-bearing antibiotic resistance gene is transferred into E. coli cells, the host cells transform into antibiotic-resistant cells.
  • If such bacteria are transferred on a culture plate containing the respective antibiotic, only the resistant forms will grow and the others will die.
  • The antibiotic resistance gene acts as a selective marker in this case.

Answered by Sheetal Kolte | 19th Jul, 2019, 11:03: AM

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