  Reputed intractable, the question of the origin of viruses has long been
neglected. In the modern literature 'Virus evolution' has come to refer to
study more akin to population genetics, such as the world-wide scrutiny on new
polymorphisms appearing daily in the H5N1 avian flu virus [1], than to the
fundamental interrogation: where do viruses come from? This situation is now
rapidly changing, due to the coincidence of bold new ideas (and sometimes the
revival of old ones), the unexpected features exhibited by recently isolated
spectacular viruses [2] (see at URL: www.giantvirus.org), as well as the steady
increase of genomic sequences for 'regular' viruses and cellular organisms
enhancing the power of comparative genomics [3]. After being considered
non-living and relegated in the wings by a majority of biologists, viruses are
now pushed back on the center stage: they might have been at the origin of DNA,
of the eukaryotic cell, and even of today's partition of biological organisms
into 3 domains of life: bacteria, archaea and eukarya. Here, I quickly survey
some of the recent discoveries and the new evolutionary thoughts they have
prompted, before adding to the confusion with one interrogation of my own: what
if we totally missed the true nature of (at least some) viruses?
