6 – The Second Fact of Comparative Genomics: Functional Convergence at the Molecular Level

摘要: Publisher Summary Members of a family are on average more similar to each other than members superfamily which the belongs. The most important point remember is that sequences within family, as well or hyperfamily, homologous: they share common ancestor. support for hypothesis such an ancestor existed comes from statistics database search or, with clusters orthologous groups project, symmetric BeTs across several genomes. However, degree sequence similarity—be it percentage identity, similarity score, score density—may be different family. evolutionary connections among proteins, whole families and superfamilies discovered constantly. There many ways in this can lead new structural, functional, inferences. This chapter examines types Most completely sequenced genomes belong microorganisms endowed rich intermediate metabolism but have somewhat limited repertoire functions. also discusses examples related enzymes make up metabolic pathways and, lesser extent, proteins involved genome replication expression. notion analogy at molecular level, however, remains valid structural signal transduction circuits, gene products classes biological processes.