Complex Loci in Microorganisms

Demerec, Milislav; Hartman, Philip

doi:10.1146/annurev.mi.13.100159.002113

Cited by 117 publications

(52 citation statements)

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“…Currently we understand that genes encoding the same biological pathways tend to group into operons, possibly to facilitate cotranscription (1)(2)(3) and to provide stoichiometry, thanks to the discovery of operons 50 years ago (2,4). In addition to this important understanding about the local arrangement of genes in a genome, we began to understand some global properties of bacterial genomes.…”

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Genomic arrangement of bacterial operons is constrained by biological pathways encoded in the genome

Yin

Zhang

Olman

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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It is generally known that bacterial genes working in the same biological pathways tend to group into operons, possibly to facilitate cotranscription and to provide stoichiometry. However, very little is understood about what may determine the global arrangement of bacterial genes in a genome beyond the operon level. Here we present evidence that the global arrangement of operons in a bacterial genome is largely influenced by the tendency that a bacterium keeps its operons encoding the same biological pathway in nearby genomic locations, and by the tendency to keep operons involved in multiple pathways in locations close to the other members of their participating pathways. We also observed that the activation frequencies of pathways also influence the genomic locations of their encoding operons, tending to have operons of the more frequently activated pathways more tightly clustered together. We have quantitatively assessed the influences on the global genomic arrangement of operons by different factors. We found that the current arrangements of operons in most of the bacterial genomes we studied tend to minimize the overall distance between consecutive operons of a same pathway across all pathways encoded in the genome.bacterial genome | bioinformatics | genome organization | nucleoid | neighboring genes

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confidence: 99%

Genomic arrangement of bacterial operons is constrained by biological pathways encoded in the genome

Yin

Zhang

Olman

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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“…In order to evolve toward a nuclear compartmentalization, selection had to work on the variability of the effects of cluster genes with topological meaning (McClintock, 1951). This is in line with the selection theory for gene clustering (Demerec and Hartman, 1959) and for our present need for a long evolutionary history for L1 retrotransposons as well as for the widespread presence of reverse transcriptase genes (which are useless). From the relentless attack of parasites in the Proterozoic (or early Cambrian), metazoan organisms originated the fantastic amount of "junk" DNA; products of sequences rendered innocuous to the normal genome.…”

Section: Junk Dna Increased Non-coding Digital Informationmentioning

confidence: 92%

New TheoryA genomic parasite in the evolution of metazoan development

Hoenigsberg¹,

Sanabria²

2009

Genet. Mol. Res.

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ABSTRACT. It is a challenge to understand how development emerged as a mechanism to dismantle and dismiss the intromission of foreign parasites in order to consolidate a higher-level multicellular unit of selection where more heritable variations in fitness, required for complex organization, can be procured. Levels in biological hierarchy genes, networks of genes, chromosomes, cells, organisms, etc., possess heritable variations in fitness to varying degrees, and as such, they function as units of selection in the evolutionary process [Lewontin, (1970). The units of selection. Annu. Rev. Ecol. Syst. 1: 1-18]. To proceed from each of these levels to the next constitutes a major transition in evolutionary history. When analyzing the splendid road epitomized by these transitions in units of selection, it is possible to conceive three processes: firstly, the molecular "recognition" of the "convenience" of exchanging the higher energy cost of cooperating cells with more fitness than single-cell selection (after that first recognition the emergence of 897 ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 8 (3): 896-914 (2009) Evolvability and evolutionary constraints as fingerprints of selection cooperation among cells is possible); secondly, the establishment of the mechanisms to regulate conflict, and finally, the regulation of cell differentiation and compartmentalization.

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“…By ordering mutants which show the phenomenon of interallelic cornplementation, complementation maps of loci are obtained (Giles, 1958;Ahmad and Catcheside, 1960). These maps comprise a number of subunits each of which was first designated as complementation unit by Demerec andHartman (1959). De Serres (1963) "abbreviated the latter term to cornplon to provide an operational term for the subgroups on a complementation map similar to Benzer's recon, muton, and cistron" (Benzer, 1957).…”

Section: Discussionmentioning

confidence: 99%