fixed in natural populations? And finally, why do
some pathways evolve faster than others? We have
reviewed studies that are beginning to provide
answers to some of these questions. Although we are
far from answering them completely, there is light at
the end of the tunnel: whole-genome analysis, in
combination with the generation of functional toolkits
for some non-model organisms in informative
phylogenetic positions (such as non-dipteran insects
and nematodes other than C. elegans), offers the
opportunity to address several of these questions in
the years to come.