  Complexity in biology is often described using a multi-map architecture,
where the genotype, representing the encoded information, is mapped to the
functional level, known as the phenotype, which is then connected to a latent
phenotype we refer to as fitness. This underlying architecture governs the
processes that drive evolution. Moreover, natural selection, along with other
neutral forces, can modify these maps. At each hierarchical level, variation is
observed. Here, I propose the need to establish principles that can aid in
understanding the transformation of variation within this multi-map
architecture. Specifically, I will introduce three, related to the presence of
modulators, constraints, and the modular channeling of variation. By
comprehending these design principles in various biological systems, we can
gain better insights into the mechanisms underlying these maps and their
evolutionary dynamics.
