Neutrally Evolving Interlocking Complexity in the Quandary Den

Molecular biology features numerous complexes of proteins that coordinate in an interlocking fashion to fulfill different functions. Adaptive evolution explains some of this complexity, but needn't be the default when neutral explanations suffice. A new artificial life model ``organism,'' the Quandary Den, is introduced to explore different neutral evolution scenarios where complexity increases in the absence of greater informational needs. Two interlocking complexity scenarios emerge. Subfunctionalization leads to functionality diffusing through the complex. Masking allows intracomplex interference to accumulate genetically, requiring that it be blocked at the level of expression.