The evolution of the Hh-signaling pathway genes: a computer-assisted study.

Positive selection of genes that comprise signaling cascades and play the paramount role in the development of multicellular organisms is critical to our understanding of the reasons for the evolution of embryonic development. In this work, we analyze the evolution of 9 genes involved in the function of the Hh signaling cascade. We demonstrated that positive selection is a characteristic feature of the protein domains, encoded by gene regions, whose functions are related to the molecular mechanisms of development. We also found that the positive selection of Hh-signaling cascade transcription factors, morphogens, their development-related receptors and intracellular signal transduction factors are related to the divergence of the Bilateria taxonomic types.