Question

A transgenic food crop which may help in solving the problem of night blindness in developing countries is?

• A. Bt Soybean
• B. Starlink maize
• C. Flavr Savr tomatoes
• D. Golden rice

Answer 1

The correct option is D

Golden rice

The correct option is D.

Explanation of correct option:

1. People with night blindness have poor vision during the night or in low-light environments. It occurs due to a deficiency of vitamin A.
2. Transgenic food crops are plants produced by recombinant DNA technology. The DNA of these plants has been altered by introducing new genes.
3. An example of a transgenic crop is golden rice which was produced by incorporating two genes into the rice genome.
4. One gene (crtI) that codes for carotene desaturase were isolated from a soil bacterium; another gene (psy) was isolated from daffodil and it codes for phytoene synthase.
5. Golden rice has been engineered to produce β-carotene, a precursor of vitamin A.
6. Hence, it may help in solving the problem of night blindness in developing countries.

Explanation of incorrect option:

Option A:

1. Bt soybeans have been genetically modified by introducing the Bt toxin gene (cry) from Bacillus thuringiensis.
2. Bt toxin is an insecticidal protein. It kills the insects by creating pores in midgut epithelial cells, thereby causing cell swelling and lysis.

Option B:

1. Starlink maize is a transgenic pest-resistant crop.
2. It has been produced by using a gene for glufosinate resistance and a Bt toxin gene named Cry9C.

Option C:

1. Flavr Savr tomato is a transgenic tomato that was developed by using antisense RNA that interferes with the formation of polygalacturonase.
2. Polygalacturonase is an enzyme that degrades pectin, resulting in fruit softening. The transgenic tomato doesn’t produce the enzyme and therefore retains a longer shelf life.

Final answer:

A transgenic food crop that may help in solving the problem of night blindness in developing countries is golden rice.