Question

The genetic material of is
A. ssDNA
B. ssRNA
C. dsDNA
D. dsRNA

Answer 1

Hint: The $$\varphi \times 174$$ is a type of Icosahedral phages. It is composed of DNA which is single-stranded and attacks Escherichia coli which is a bacterium.

Step by step answer:The Bacteriophage $$\varphi \times 174$$ was the first DNA-based virus whose genome was sequenced by Fred Sanger and his team in 1977. It has a characteristic physical feature of covalently closed circularity. The $$\varphi \times 174$$ virus particles were also first to be assembled in vitro from synthesized oligonucleotides.
The genetic material refers to the type of nucleic acid present inside the viral protein capsule.
The ssDNA or single-stranded DNA (Deoxyribonucleic acid) molecule is composed of a single strand of DNA with the same chemical composition of Double helical DNA. It has a stellate or star form. It is present in very few viruses such as Bacteriophage $$\varphi \times 174$$.
The ssRNA or single-stranded RNA (Ribonucleic acid) is a single-stranded genome found in viruses. It can be positive sense ssRNA or negative sense ssRNA each having their characteristic virulence level. The ssRNA viruses mainly infect human cells. For example, SARS-Cov-2 is positive-sense ssRNA and is highly contagious.
The dsDNA means double-stranded or double helix DNA molecule which is found in complex organisms. The Bacteriophage $$\varphi \times 174$$ do not have dsDNA.
The dsRNA is a double-stranded RNA molecule. This is present as the genetic material in many polyphyletic groups of viruses. But it is not the genetic material in $$\varphi \times 174$$. Reoviridae is the largest family having dsRNA as its genetic material.
So, the genetic material in Bacteriophage $$\varphi \times 174$$ is single-stranded DNA or ssDNA.
Thus, option A is the correct answer.

Note: The ss stands for single-stranded and ds stands for double-stranded. The Bacteriophage $$\varphi \times 174$$ is a very interesting ssDNA virus to be studied as it was the first virus to be discovered having ssDNA as its genetic material. Its DNA is made up of 5386 nucleotides which were decoded by the Sanger sequencing technique of DNA sequencing.