Baby hamster kidney cells (BHK)
B: VSV infected
BHK cell plates stained with crystal
violet, showing virus plaques.
excellent model systems for studying evolution
because they evolve fast under lab conditions,
which allows us to do 'real time' analyses.
Moreover, their small genomes facilitate
genetic manipulation and the study of the
genetic bases of adaptation. We have worked
both at the computational and experimental
levels with several viruses:
Bacteriophages. RNA (Qbeta, MS2, SP) and
single-stranded DNA (phiX174, G4, f1/m13)
coliphages, all of which infect the same host
strain, thus allowing us to perform direct
comparisons between viral species.
Vesicular stomatitis virus
a negative-stranded RNA virus belonging to the
family Rhabdoviridae. As most RNA
viruses, it has a small genome size (11 kb), a
high per-base mutation rate (~10-4-10-5),
and low tolerance to mutations (~40% random
nucleotide substitutions are lethal to the
virus). In the wild, it is of particular
importance to farmers in regions where it can
infect livestock. In the lab, it has been
extensively used for experimental evolution.
Transmissible gastroenteritis virus
(TGEV), a model coronavirus. Using samples
kindly provided by Prof.
Luis Enjuanes (CSIC, Madrid), we are
measuring the mutation rate of this virus.
Coronaviruses are probably the only RNA
viruses whose polymerases are able of
proofreading, and this should result in
relatively low mutation rates.
Hepatitis C virus (HCV)
constitutes a major global health concern. We
have analyzed sequence datasets in
collaboration with Prof.
Fernando González-Candelas to
investigate the effect of the
interferon-ribavirin therapy on the viral
HIV-1. Given the huge amount
of information available for this virus,
it constitutes an excellent model for
studying evolution at the molecular
level. For instance, in collaboration with Dr.
Antonio V. Borderia (Institut
Pasteur), we have shown that HIV-1 evolution
is constrained by selection operating
simultaneously at the RNA structure and
protein levels. We are also investigating how
immune pressure shapes HIV-1 sequence
Viroids are plant infectious agents constituted by
a minimal (200-400 nt) RNA genome that does not
code for any protein. In collaboration with the
groups of the Profs. Santiago
F. Elena and Ricardo Flores, we have
performed several in silico analyses of their
RNA secondary structure and have measured
the per-base mutation rate of a hammerhead
viroid, which turned out to be the highest
described for any biological entity.