Computational and Mathematical Methods in Medicine
Volume 9 (2008), Issue 3-4, Pages 175-181
Original Article

Classification and Evolutionary Trends of Icosahedral Viral Capsids

LPTMC, Université Paris-VI-CNRS UMR 7600, Tour 24, 4-ème, Boite 121, 4 Place Jussieu, Paris 75005, France

Received 6 January 2008; Accepted 31 March 2008

Copyright © 2008 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


A classification of icosahedral viral capsids is proposed. We show how the self-organization of capsids during their formation implies a definite composition of their elementary building blocks. The exact number of hexamers with three different admissible symmetries is related to capsids' sizes, labelled by their T-numbers. Simple rules determining these numbers for each value of T are deduced and certain consequences concerning the probabilities of mutations and evolution of viruses are discussed.