title: Compositional constraints and genome evolution.
abstract: Nucleotide sequences of all genomes are subject to compositional constraints that affect, to about the same extent, both coding and noncoding sequences; influence not only the structure and function of the genome, but also those of transcripts and proteins; are the result of environmental pressures; and largely control the fixation of mutations. These findings indicate that noncoding sequences are associated with biological functions; that the organismal phenotype comprises two components, the classical phenotype, corresponding to the "gene products," and a "genome phenotype," which is defined by the compositional constraints; and that natural selection plays a more important role in genome evolution than do random events.
mesh_terms: D001482:Base Composition; D001483:Base Sequence; D005075:Biological Evolution; D005796:Genes; D009154:Mutation; D011506:Proteins / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics
chemical_list: D011506:Proteins; D012333:RNA, Messenger