  Relation of genome sizes to organisms complexity is still described rather
equivocally. Neither the number of genes (G-value), nor the total amount of DNA
(C-value) correlates consistently with phenotype complexity. Using information
theory considerations we developed a model that allows a quantative estimate
for the amount of functional information in a genomic sequence. This model
easily answers the long-standing question of why GC content is increased in
functional regions. The model allows consistent estimate of genome
complexities, resolving the major discrepancies of G- and C-values. For related
organisms with similarly complex phenotypes, this estimate provides biological
insights into their niches complexities. This theoretical framework suggests
that biological information can rapidly evolve on demand from environment,
mainly in non-coding genomic sequence and explains the role of duplications in
the evolution of biological information. Knowing the approximate amount of
functionality in a genomic sequence is useful for many applications such as
phylogenetics analyses, in-silico functional elements discovery or prioritising
targets for genotyping and sequencing.
