Domain shuffling and the increasing complexity of biological networks

• Autor(a) principal: Souza, Sandro José de
• Data de Publicação: 2012
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFRN
• Texto Completo: https://repositorio.ufrn.br/jspui/handle/123456789/23250
• topic: Domain shuffling; increasing complexity; biological networks

The notion that ‘‘new’’ proteins were the major genetic units responsible for phenotypic novelty was prevalent in the late 1970s and in the 1980s. Although this notion is still valid for specific cases, especially involving master genes like PAX6, nowadays it is generally believed that new phenotypes rarely emerge through the origin of a completely new protein [1]. Many alternatives have been proposed. Some authors, for example, have suggested that altered gene expression patterns are responsible for the emergence of new traits [2, 3]. The availability of genome-wide datasets from a variety of species and the consequent emergence of more systemic views on how genes and proteins act has led us to understand that the evolution of biological novelty (and consequently complexity) is a direct consequence of new functional pathways and modules or the rewiring of pre-existing ones. But how have these biological networks evolved? Most of the studies on this problem are centered on protein-protein interaction (PPI) networks, especially because of the availability of this type of data for many species. Many authors have shown that gene or genome duplication seems to have an important role in the evolution of PPI networks [4–6]. In support of this, paralogous proteins present a conserved pattern of interactions and therefore share more partners than expected by chance [5]. Furthermore, networks modeled according to this duplication/ divergence idea display topological properties very similar to real biological networks [4, 7, 8]. Pereira-Leal et al. [6] showed that duplication of self-interaction nodes is crucial for the evolution of more interconnected networks. Compared to gene and genome duplication, little attention has been dedicated to domain shuffling.