Biotechnology- Principles and Processes Question 6
6. A selectable marker is used to : [2019, Odisa]
(a) Mark a gene on a chromosome for isolation using restriction enzyme.
(b) Help in eliminating the non-transformants, so that the transformants can be regenerated.
(c) Identify the gene for a desired trait in an alien organism.
(d) Select a suitable vector for transformation in a specific crop.
Show Answer
Answer : b
Hints & Solutions
(b) Selectable marker is a gene introduced into a cell, especially a bacterium or to cells in culture that confers a trait suitable for artificial selection. Selectable markers help in identification and elimination of non-transformants whilst permitting selective growth of transformants. Note: Selectable marker genes are conditionally dominant genes that confer an ability to grow in the presence of applied selective agents that are normally toxic to plant cells or inhibitory to plant growth, such as antibiotics and herbicides. Genes that are frequently used to select transformed plant tissues include nptII, hpt, bar, and gox, that confer resistance to kanamycin, hygromycin, phosphinothricin, and glyphosate, respectively. Commonly used selectable marker systems include neomycin phosphotransferase, hygromycin phosphotransferase, phosphoinothricin acetyltransferase, and glyphosate oxidoreductase. Use of nptII in concert with the antibiotic kanamycin has become the most widely used selectable marker.
