Lwoff v.s Baltimore:

Lwoff’s scheme for classification:

Four main characteristics are used:

1. Nature of the nucleic acid: RNA or DNA

2. Symmetry of the capsid

3. Presence or absence of an envelope

4. Dimensions of the virion and capsid

Baltimore’s scheme for classification:

Based on the method of viral mRNA synthesis.

http://expasy.org/viralzone/all_by_protein/254.html

http://www.nlv.ch/Virologytutorials/graphics/classificationtotal.jpg

 

IN SUMMARY:

VIRAL CLASSIFICATION
Nucleic acid	RNA or DNA
	single-stranded or double-stranded
	non-segmented or segmented
	linear or circular
	if genome is single stranded RNA, can it function as mRNA?
	whether genome is diploid (such as in retroviruses)
Virion structure	symmetry (icosahedral, helical, complex)
	enveloped or not enveloped
	number of capsomers