The Viral Talk

Episode 7 - Viral Diversity

The Viral Talk

Show Notes

How many types of viruses are there? How do scientist classify them and why is it important to know? This and much more in this episode of the Viral Talk.

Key takeaways:

Scientists predict hundreds of millions of different viral species on our planet, but they can all be grouped in 'only' seven different groups.

These seven groups have been theorized by virologist David Baltimore based on the different types of genomes they can have, and how this affects the way in which they replicate.

In nature, almost all organisms follow the central dogma of biology: DNA->RNA->Proteins. But not all viruses follow it.

The seven groups are:

double stranded DNA viruses (e.g. herpesviruses)

single stranded DNA viruses (e.g. many bacterial viruses)

double stranded RNA viruses (e.g. rotaviruses)

positive sense single stranded RNA viruses (e.g. coronaviruses)

negative sense single stranded RNA viruses (e.g. Influenza virus)

double stranded RNA viruses with DNA intermediate (e.g. HIV)

double stranded DNA viruses with RNA intermediates (e.g. Hepatitis B virus)

Knowing how viruses replicate beforehand can give us a heads-up on potential targets for antiviral drug development.

Examples include antivirals against HIV and other retroviruses.

For people who'd like to know more:

Original paper on Baltimore classification - DOI: 10.1128/br.35.3.235-241.1971

Success story on antivirals against HIV: DOI: 10.1016/S0166-3542(98)00025-4

Visual explanation of Baltimore classification scheme: https://www.youtube.com/watch?v=W2YOZnvgcuk&ab_channel=Shomu%27sBiology

Follow The Viral Talk on Instagram - https://www.instagram.com/the_viral_talk_/

And Twitter - https://twitter.com/The_Viral_Talk

Contact The Viral Talk via email - [email protected]

Leave a Review of the episode on Podchaser.com - https://www.podchaser.com/podcasts/the-viral-talk-5094049

More from The Viral Talk

Jan 22, 2026

Welcome to the 2nd season of 'Ask a Professional', the format of The Viral Talk where the focus is on the science but most importantly on the PEOPLE behind the science. From insect-borne viruses to SARS-CoV-2 and Influenza, here is where we interview experts from the UK and the world on their research, career, aspirations and on how to prepare the next generation of scientists.

Jan 15, 2026

How do our bodies remember a virus they haven't seen in a decade? What exactly makes the "adaptive" part of our immune system so much more specialized than our innate defenses? This and much more in this new episode of The Viral Talk.

Aug 18, 2025

What do scientists mean when they talk about the innate immune system? What are the differences between innate and adaptive immunity? What is the immune system composed of? This and much more in this episode of The Viral Talk.

Jul 27, 2025

This is 'Ask a professional', the format of the Viral Talk where the focus is on the science but most importantly on the PERSON behind the science. From insect-borne viruses to SARS-CoV-2 and vaccines, we're going to interview experts from the UK and the world on their research, career, future prospects and tips for the younger generations of scientists. In this episode Federico interviews Dr Valerie Odon, newly appointed group leader at the University of Strathclyde in virology. In this episode we're gonna talk about cells investigating intruders (viruses), the wisdom of mothers and the challenges that come with becoming your own boss.

Mar 6, 2025

What does the term co-infection mean? What happens when two viruses infect us at the same time and why is it important for our health? This and much more in this episode of The Viral Talk.

See all episodes →