Evolutionary Transformations of the Metazoan Body Plan: Genomic-Morphogenetic Correlations.

This review summarizes literature data on phylogenomics, indicating genomic–morphogenetic correlations that determine the metazoan body plan and phenotypic complexity. Radical, macroevolutionary transformations of the bilaterian body plan, which correlate with duplications or losses of individual Hox genes of an ancestral cluster, or with its topological reorganization, are revealed. Regressive evolution is rather common in Metazoa; reduction and simplification of the genome and phenome occurred quite often in the evolution of metazoans. Since the system of cluster Hox genes has been shown to be the key regulatory node of genome–phenome relationships, regulating a wide range of developmental processes, as well as being the correlation node determining different evolutionary trajectories of various bilaterian taxa, it is a highly informative correlate and indicator of evolutionary changes of the body plan. [ABSTRACT FROM AUTHOR]