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Consider the following statements
$I.$ In microinjection method foreign $DNA$ is directly injected into the nucleus of animal cell or plant cell by using micro needles or micro pipettes
$II.$ Microinjection method is used in oocytes, eggs and embryo
$III.$ Electroporation is the formation of temporary pores in the plasma membrane of host cell by using lysozyme or calcium chloride
$IV.$ In chemical mediated gene transfer method certain chemicals such as $\mathrm{CO}_{2}$ help foreign $DNA$ to enter the host cell
Which of the statements given above are correct?
$I \;and\; II$
$I, II\;and\; III$
$II, III \;and\; IV$
$I, II, III\; and \;IV$
Solution
Microinjection $DNA$ is directly injected into plant protoplasts or cells (specifically into the nucleus or cytoplasm) using fine tipped ($0.5-1.0$ micrometer diameter) glass needle or micropipette. This method of gene transfer is used to introduce $DNA$ into large cells such as oocytes, eggs, and the cells of early embryo. Electroporation It involves a pulse of high voltage applied to protoplasts/cells/tissues to make transient (temporory) pores in the plasma membranes which facilitates the uptake of foreign $DNA$. The cells are place in a solution containing $DNA$ and subjected to electrical shock to cause holes in the membranes. The foreign $DNA$ fragments enter through the holes into the cytoplasm and then to nucleus. Chemical Mediated Gene Transfer Chemicals like Polyethylene Glycol $(PEG)$ and sulphate induce $DNA$ uptake into plant protoplasts. Calcium phosphate is also used to transfer $DNA$ into cultured cells
