Question

Transduction was discovered in bacteria by
A. Lederberg and Tatum
B. Zinder and Lederberg
C. Wallace and Jacob
D. Herelle and Twort

Answer 1

Hint: Bacteria are unicellular organisms and are capable of transferring genes from one cell to another bacterial cells. This process can occur through various methods such as transduction, conjugation and translocation. Transduction is a natural process, in which DNA is transported from one bacterium to another through a virus. In this process, a foreign DNA is introduced into another cell via a viral vector. As the process is done by a virus, physical contact is not seen in between the cells.

Complete answer:
Transduction is the process by which a foreign DNA is introduced into a cell by a virus i.e. in this process a DNA is transferred in between cells by a viral vector. Horizontal gene transfer is an example of transduction where the viral transfer of DNA takes place from one bacterium to another. Transduction does not require physical contact between the cell between the cell that donates the DNA and the other cell which receives the DNA. It is a common process used to stably introduce a foreign gene into a host cell's genome.
Bacteriophages are such a virus that has the ability to infect a bacterial cell. They behave as hosts and produce more viruses. After production, these viruses joint together and remove a portion of the bacterial DNA of the host cell. This portion of bacterial DNA which is removed gets organized with the genome of the new host and this process occurs when the new host cell is infected by the viruses or bacteriophages. Transduction takes place through either the lytic cycle or the lysogenic cycle.
Basically, two types of transduction are observed in bacteria and that are generalized transduction and specialized transduction. In the case of generalized transduction, any portion of the bacterial DNA can be picked up by the bacteriophages. But in the case of specialized transduction, a definite portion of the host's DNA is picked up by the bacteriophages.
Transduction was discovered by Joshua Lederberg and Norton Zinder while working on the recombination of genes in bacteria and they used this technique of transfer viral DNA and applied to the bacterium Salmonella typhimurium.
The conjugation process of reproduction in the bacterial cells was discovered by Lederberg and Tatum in E.coli. It is the process through which two bacterial cells create a cytoplasmic bridge to transfer genetic material from one cell to another.
Jacob demonstrated the lactose system in the cells through the regulation of transcription.
The existence of bacteriophage was discovered independently by Herelle and Twort and the word ‘bacteriophage’ was coined by Herelle.

Therefore, the correct answer is option B.

Note: Transduction is the process of transferring genetic material i.e. bacterial DNA from one bacterium which is known as a host to another. It is a type of horizontal gene transfer process and does not need any physical contact. This process is discovered by two American biologists, Joshua Lederberg and Norton Zinder. Transduction is important as it is used in the mechanism of antibiotic drugs transfer as an effective method due to the transfer of antibiotic-resistance genes between bacteria.