Where does viruses come from

In the recent days VIRUS is a very common term used across the globe, but do we know what they are and where the come from?  Well, on a brief note viruses are biomolecules that lives or tends to activate only when present inside a living host. This means they are non living entities that develop a living symbiotic relation when present within a living organism. In simple term viruses are identified to be an incomplete cell or a combination of protein structures that lack the full potential of sustaining life.

From this it can be stated that a virus body could have been a previously lived organism, or a degenerated cell structure. Thereby suggesting these structure to be a little or far related to an existing organism.  And hence leads to various hypothesis on its origin to classify the diverse group of viruses. Some of the very common classification of viruses are based on its morphological structures, and its genetic material type (DNA or RNA). The figure below depicts the hierarchy of viral classification based on its genetic material present.

(Source : Microbiology Learner)

From this figure it can be seen that double-stranded enveloped viruses and double-stranded un-enveloped viruses for example are closely related than the (-) RNA enveloped viruses and the double stranded enveloped DNA viruses. Hence implying how classification aids with tracing the relation between two viruses. Thereby suggesting to study the evolutionary pathways or in other words the origin of the viral development. 

So where did all these viruses come? Well this question is still debated upon the three main hypothesis known as the progressive hypothesis, the regressive hypothesis, and the virus first hypothesis. 

1) The progressive hypothesis suggests that viruses could have evolved when a genetic material was able to move from one cell to another.    

2) The regressive hypothesis states that viruses could have been pre-lived organism that had lost some parts of its genetic information leading to be unable to sustain life.  

3) The virus - first hypothesis states that viruses could have existed even before life formed. 

However logically reasonable these hypothesis are its is still a question of where viruses originated. The debate continues, detailing further researches on the process of classification and tracing of the viral histories.