Baltimore's Classification

One of them was Nobel laureate in Physiology or Medicine, David Baltimore.

He founded the "Baltimore's Classification", which classifies viruses into different families based on their type of genome and method of replication.

There are 7 families in this system:

1 - Double stranded DNA viruses

2 - Single stranded DNA viruses

3 - Double stranded RNA viruses

4 - Positive sense single stranded RNA viruses

5 - Negative sense single stranded RNA viruses

6 - Single stranded reverse transcribing RNA viruses

7 - Double stranded reverse transcribing DNA viruses

This system of classification is widely used today.

Introduction to Viruses

The world of viruses is as diverse as it is large.

Ignored by humans since ancient time, viruses went on to cause many different types of diseases which were either diagnosed as (This was really looong ago!) being cursed or being possessed by a spirit.

Later, as science progressed, man discovered bacteria in 1676. "Cursed" or "Spiritual Possession" diseases were subsequently (and proudly might I add) blamed on these hot new microorganisms by prominent biologists.

It was only more than 200 years later, in 1884, that scientists finally accepted their misconception with the isolation of tobacco mosaic virus by French microbiologist Charles Chamberland.

With that vital discovery, scientists rapidly began to step into uncharted territory, fueling the growth of the science that is now known as virology.

Many major discoveries have been made since then, including developing the first virus images and discovering that viruses were almost entirely composed by protein.

Towards the end of the 20th century, armed with the knowledge of virus structure, scientists began analyzing all known viruses in a bid to classify them...