Question

Which of the following correctly defines a transgenic animal ?

• A. An animal which has foreign DNA in all its cells because transgene is microinjected into the pronuclei of the fertilised egg from which it is developed
• B. An animal which has foreign DNA and RNA in some of its cells because of the insertion of DNA into the somatic cells
• C. An animal which has foreign DNA and RNA in some of its cells because of the microinjection of DNA and RNA into the pronucleus of the fertilised egg
• D. An animal which has foreign DNA in some of its cells because of the microinjection of the transgene into the embryonic cells

Answer 1

The correct option is A An animal which has foreign DNA in all its cells because transgene is microinjected into the pronuclei of the fertilised egg from which it is developed

In a transgenic animal foreign DNA is present in all cells if the transgene is microinjected into the pronuclei of the fertilised egg from which it develops. Pronucleus is the haploid nucleus of either the male or female gamete, both present in the fertilised egg prior to their fusion.

Transgenic animals with all cells having transgene can also be created by inserting DNA into the embryonic cells. These cells are then micro-injected into an embryo which has developed for five or six days after fertilisation.

By inserting transgene into the somatic cells, only some of its cells will contain DNA, which will not create transgenic descendants. Also RNA is not inserted for the creation of the transgenic animals.