What is the Difference Between RNA Viruses and Retroviruses

The key difference between RNA Viruses and retroviruses is that RNA viruses are viruses that have single-stranded or double-stranded RNA as their genetic material, while retroviruses are viruses that have single-stranded RNA as their genetic material but use DNA intermediates in their life cycle.

Virus classification is the process of naming viruses and placing them into a taxonomic system. This system is similar to the classification systems that are used for cellular organisms. Based on the type of nucleic acids, viruses can be classified as DNA viruses (adenovirus, human parvovirus), RNA viruses (rotavirus), and reverse transcribing viruses (retrovirus).

CONTENTS

1. Overview and Key Difference
2. What are RNA Viruses 
3. What are Retroviruses
4. Similarities – RNA Viruses and Retroviruses
5. RNA Viruses vs Retroviruses in Tabular Form
6. Summary – RNA Viruses vs Retroviruses

What are RNA Viruses?

RNA viruses are viruses that have single-stranded or double-stranded RNA as their genetic material. According to the International Committee on Taxonomy of Viruses (ICTV), RNA viruses are the viruses that belong to group III, group IV, or group V of the Baltimore classification system. Moreover, as of 2020, all known RNA viruses that encode RNA-directed RNA polymerases come under a monophyletic group called the realm Riboviria. The majority of these RNA viruses fall into the kingdom of Orthornavirae, and the rest of the RNA viruses have a positioning not yet defined.

Single-stranded RNA viruses include enterovirus, rhinovirus, Norwalk virus, influenza A, B, C viruses, rabies virus, Ebola virus, hepatitis E virus, etc. Double-stranded RNA viruses include reovirus and rotavirus. Furthermore, RNA viruses usually have very high mutation rates compared to DNA viruses. This is because the viral RNA polymerases of RNA viruses lack the proofreading ability of DNA polymerases. Some of the notable human diseases caused by RNA viruses include the common cold, SARS, MERS, influenza, dengue, hepatitis C, hepatitis E, West Nile fever, Ebola virus disease, rabies, polio mumps, and measles.

What are Retroviruses?

Retroviruses are viruses that have a single-stranded RNA as their genetic material and replicate using a DNA intermediate. Upon infection with these retroviruses, retroviral RNA converts into the DNA, which in turn is inserted into the DNA of the host cells. Then the cell produces more retroviruses that can infect other cells as well. The reverse transcriptase enzyme is used by retroviruses to produce DNA from their RNA genome. The new DNA is incorporated into the host cell genome by a retroviral integrase enzyme.

Although retroviruses have different subfamilies, they have three basic groups. They are oncoretroviruses, lentiviruses, and spumaviruses. Furthermore, many retroviruses cause serious diseases in humans, other mammals, and birds. Human retroviruses HIV-1 and HIV-2 cause AIDS disease. Human T-lymphotropic virus (HTLV) causes adult T cell leukemia/lymphoma. The murine leukemia viruses (MLVs) cause cancer in mouse hosts. Retroviruses are a valuable tool in molecular biology, and they have been successfully used in gene delivery systems.

What are the Similarities Between RNA Viruses and Retroviruses?

• RNA Viruses and retroviruses are two types of viruses that have RNA as genetic material.
• Both types of viruses have specific enzymes that help them to complete their life cycle.
• These types of viruses have a high mutation rate.
• Both types of viruses use humans and other animals as hosts.
• They cause serious diseases in humans.

What is the Difference Between RNA Viruses and Retroviruses?

RNA viruses are viruses that have a single-stranded or double-stranded RNA as their genetic material, while retroviruses are viruses that have a single-stranded RNA as their genetic material but use DNA intermediates in their life cycle. Thus, this is the key difference between RNA Viruses and retroviruses. Furthermore, the hosts of RNA viruses include humans, animals, plants, and fungi, while hosts of retroviruses include humans, other mammals, and birds.

The below infographic presents the differences between RNA Viruses and retroviruses in tabular form for side by side comparison.

Summary – RNA Viruses vs Retroviruses

Both RNA Viruses and retroviruses have RNA as the genetic material. RNA viruses are a common group of RNA viruses that have single-stranded or double-stranded RNA as their genetic material. Retroviruses are viruses that have a single-stranded RNA as their genetic material, but they use DNA intermediates in their life cycle. So, this is the key difference between RNA Viruses and retroviruses.

Reference:

1. “RNA Virus.” An Overview | ScienceDirect Topics.
2. “Retrovirus.” Encyclopædia Britannica, Encyclopædia Britannica, Inc.

Image Courtesy:

1. “Viruses-12-00504-g001” By Hi Eun Jung and Heung Kyu Lee (CC BY 4.0) via Commons Wikimedia
2. “HTLV Phylogeny” By Tylercj2 – Own work (CC BY-SA 4.0) via Commons Wikimedia