In plants, competency of the host to take up the recombinant DNA is enabled by using ______ technique.
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Biolistics
Option (1) Insertional inactivation — Incorrect. It is a way to pick out recombinants: the alien DNA put into a marker gene stops that gene from working. It does not take DNA into a cell.
Option (2) Micro injection — Incorrect. Recombinant DNA is injected straight into the nucleus of an animal cell. Plant cells, with their walls, are not handled this way.
Option (3) Biolistics — Correct. Plant cells are bombarded with tiny gold or tungsten particles coated with DNA (gene gun); this method suits plants.
Option (4) Gel electrophoresis — Incorrect. It separates DNA fragments by size in an agarose gel; it puts no DNA into a host.
NCERT Extract:
Cloning Vectors – “… Recombinant DNA can then be forced into such cells by incubating the cells with recombinant DNA on ice, followed by placing them briefly at 420C (heat shock), and then putting them back on ice. This enables the bacteria to take up the recombinant DNA. This is not the only way to introduce alien DNA into host cells. In a method known as micro-injection, recombinant DNA is directly injected into the nucleus of an animal cell. In another method, suitable for plants, cells are bombarded with high velocity micro-particles of gold or tungsten coated with DNA in a method known as biolistics or gene gun. And the last method uses ‘disarmed pathogen’ vectors, which when allowed to infect the cell, transfer the recombinant DNA into the host.”