The genome sequences of many uncultured Archaea may
provide clues from possible proviruses in their sequences that
will allow the molecular screening of virus-sized samples from
the oceans or soils without the need for cultivation of hosts,
which is the critical bottleneck in the study of archaeal
viruses. Additionally, metagenomic projects allow the identification
of further viruses. For example, a halovirus-like
sequence, EHP-1, has been recovered directly from a crystallizer
pond, although the virus itself has yet to be isolated (Santos
et al. 2007).