Question

Which of the following genes were introduced in cotton to protect it from cotton bollworms?
A. CryAc and CryAb
B. BtAc and BtAb
C. CryIAc and CryIIAB
D. Nif genes

Answer 1

The cotton bollworm is a moth species that eats on the fully grown cotton plants. They destroy a large number of crops at once which leads to a decrease in yield and deterioration in quality. Using recombinant DNA technology, the cotton genes were modified to prevent bollworm manifestation.

Complete answer: The cotton bollworm moths are a major threat to cotton fields. They eat on the fully grown cotton plant and destroy the crop yield. To combat this problem, Bt cotton was made using recombinant DNA technology. In this technology, a specific desired segment of the gene is transferred from the genome of the donor to the host. In the Bt cotton production, the host was cotton plant genome and the donor was Bacillus thuringiensis. This bacterium produces over 200 types of different Bt toxins that are lethal to different insects. The Bt toxins act as insecticides to cotton bollworms, moths, and butterflies. The genes that code for these toxins were taken from the genome of the bacteria and were inserted into the genome of the cotton plant using vectors. The Bt cotton was created using a group of endotoxin genes called Cry genes. The two main genes releasing Bt-toxins named CryIAc and CryIIAb were isolated from the bacterium genome and then inserted in the cotton plant genome. After this, the modified cotton plants were cultivated and improvement was seen. Now, whenever the bollworms tried to eat the cotton plant they died. The Bt toxins when entering the gut of bollworms, create pores in it causing leakage and sudden death.
Thus, the right answer is option C.

Note: The recombinant DNA technology offers the production of a variety of genetically modified organisms. These are called GMOs. The Bt cotton was the first successfully made GMO which was accepted and grown by public acceptance. Any carelessness in the production of GMOs and their release in nature can be harmful. Thus, it is a complicated procedure to develop GMOs.