Question

Foreign DNA can NOT be transferred into a zygote by which one of the following methods?

• A. Transduction
• B. Microinjection
• C. Electroporation
• D. Conjugation

Hint:

If the method is associated with bacteria or natural processes in prokaryotes (like conjugation), it's unlikely to be used in eukaryotic systems like zygotes. Focus on artificial methods for gene transfer in higher organisms.

Answer 1

The Correct Option is D

Step 1: Understand the meaning of a zygote. 
A zygote is a eukaryotic cell formed by the fertilization of an egg and a sperm cell. It's a single-cell embryo that will eventually develop into a multicellular organism. 
Step 2: Know the methods used to introduce DNA into a zygote. 
Microinjection: A fine glass needle is used to directly inject DNA into the zygote. This is a common and precise method used in genetic engineering of animals. 
Electroporation: High-voltage electrical pulses create pores in the cell membrane of the zygote, allowing DNA to enter. It is effective in making cells temporarily permeable. 
Transduction: Involves the use of viruses to deliver foreign DNA into a host cell. Modified viruses can be used to introduce DNA into eukaryotic zygotes.
Step 3: Understand why conjugation is not applicable. 
Conjugation is a natural gene transfer process seen in prokaryotes (like bacteria), where DNA is transferred through a pilus between two bacterial cells. 
It is not used and not possible for transferring DNA into a eukaryotic zygote because conjugation mechanisms do not exist in eukaryotic systems. Step 4: Conclude based on the above facts. 
All the first three techniques (Microinjection, Electroporation, Transduction) are artificial and suitable for zygotes. Conjugation is strictly bacterial and irrelevant to genetic manipulation of zygotes.