  At odds with a traditional view of molecular evolution that seeks a
descent-with-modification relationship between functional sequences, new
functions can emerge {\it de novo} with relative ease. At early times of
molecular evolution, random polymers could have sufficed for the appearance of
incipient chemical activity, while the cellular environment harbors a myriad of
proto-functional molecules. The emergence of function is facilitated by several
mechanisms intrinsic to molecular organization, such as redundant mapping of
sequences into structures, phenotypic plasticity, modularity, or cooperative
associations between genomic sequences. It is the availability of niches in the
molecular ecology that filters new potentially functional proposals. New
phenotypes and subsequent levels of molecular complexity could be attained
through combinatorial explorations of currently available molecular variants.
Natural selection does the rest.
