Working with mice, and pairing new computational methods with high speed
sequencing, we now determine the causes of phenotypes in real time. When
a phenotype induced by a germline mutagen is detected, its mutational cause is
instantly known as well. Approximately one third of the mouse genome has
so far been damaged or destroyed under close phenotypic surveillance.
Many new proteins, not previously known to participate in immunity, have been
identified in this way. Moreover, it is possible to use the same system
to identify mutations that eliminate disease. Disease modifier loci can,
in some cases, be attractive targets for drug development.