01857nas a2200169   4500008004100000245008800041210006900129300001200198490000800210520119800218653001501416653010001431100001901531700001801550700001301568856010601581       2005                        eng d00aVariation and evolution of biomolecular systems: searching for functional relevance0 aVariation and evolution of biomolecular systems searching for fu  a1839-450 v5793 aThe availability of genome sequences and functional genomics data from multiple species enables us to compare the composition of biomolecular systems like biochemical pathways and protein complexes between species. Here, we review small- and large-scale, "genomics-based" approaches to biomolecular systems variation. In general, caution is required when comparing the results of bioinformatics analyses of genomes or of functional genomics data between species. Limitations to the sensitivity of sequence analysis tools and the noisy nature of genomics data tend to lead to systematic overestimates of the amount of variation. Nevertheless, the results from detailed manual analyses, and of large-scale analyses that filter out systematic biases, point to a large amount of variation in the composition of biomolecular systems. Such observations challenge our understanding of the function of the systems and their individual components and can potentially facilitate the identification and functional characterization of sub-systems within a system. Mapping the inter-species variation of complex biomolecular systems on a phylogenetic species tree allows one to reconstruct their evolution.10a*Evolution10aMolecular Genetic Variation Multiprotein Complexes/*genetics Phylogeny Protein Binding/genetics1 aHuynen, M., A.1 aGabaldón, T.1 aSnel, B.  uhttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=15763561