Evolution concerted

A number of approaches have been tried for modified halo-de-diazoniations using l-aryl-3,3-dialkyltriazenes, which form diazonium ions in an acid-catalyzed hydrolysis (see Sec. 13.4). Treatment of such triazenes with trimethylsilyl halides in acetonitrile at 60 °C resulted in the rapid evolution of nitrogen and in the formation of aryl halides (Ku and Barrio, 1981) without an electron transfer reagent or another catalyst. Yields with silyl bromide and with silyl iodide were 60-95%. The authors explain the reaction as shown in (Scheme 10-30). The formation of the intermediate is indicated by higher yields if electron-withdrawing substituents (X = CN, COCH3) are present. In the opinion of the present author, it is likely that the dissociation of this intermediate is not a concerted reaction, but that the dissociation of the A-aryl bond to form an aryl cation is followed by the addition of the halide. The reaction is therefore mechanistically not related to the homolytic halo-de-diazoniations. 

Arnheim, N. (1983) Concerted evolution of multigene families. In Nei, M. and Koehn, R.K. (eds) Evolution of Genes and Proteins. Sinauer, Sunderland, Massachusetts, pp. 38-61. 

Elder, J.F. and Turner, B.J. (1995) Concerted evolution of repetitive DNA sequences in eukaryotes. Quarterly Review of Biology 70, 297-320. 

Schlotterer, C. and Tautz, D. (1994) Chromosomal homogeneity of Drosophila ribosomal DNA arrays suggests intrachromosomal exchanges drive concerted evolution. Current Biology 4, 777-783. 

Concerted evolution apparently operates among neodermatan ribosomal operons (Collins and Cunningham, 2000). However, intraspecific and intra-individual variation is common in neodermatans and other eukaryotes, especially in spacers, and indicates that the force of concerted evolution cannot completely overcome contrary influences. Such influences include the effects of replication slippage and unequal crossing over, both of which can occur in regions of simple sequence, which is abundant in eukaryotic... 

Hillis, D.M., Moritz, C., Porter, C.A. and Baker, R.J. (1991) Evidence for biased gene conversion in concerted evolution of ribosomal DNA. Science 251, 308-310. 

Chin JW, Schepartz A. Concerted evolution of structure and function in a miniature protein. J Am Chem Soc 2001 123 2929-2930. 

In this chapter, we give a brief overview of several novel features of excited-state proton transfer in chromophore-solvent clusters which have been revealed by the interplay of computational chemistry and spectroscopy in supersonic jets. In the future, concerted efforts of theory and spectroscopy will be necessary to investigate the evolution of these phenomena with increasing cluster size towards liquid-phase photochemistry. 

A chemical reaction always involves bond-breaking/making processes or valence electron rearrangements, which can be characterized by the variation of VB structures. According to the resonance theory [1, 50], the evolution of a system in the elementary reaction process can be interpreted through the resonance among the correlated VB structures corresponding to reactant, product and some intermediate states. Because only symmetry-adapted VB structures can effectively resonate, all VB structures involved in the description of a reaction will thus retain the symmetry shared by both reactant and product states in the elementary process. Therefore, we postulate that the VB structures of the reactant and the product states for concerted reactions should preserve symmetry-adaptation, called the VB structure symmetry-adaptation (VBSSA) rule. 

Nei M, Rooney AP (2005) Concerted and birth-and-death evolution of multigene families. Annu Rev Genet 39 121-152... 

Detection and Quantification of Concerted Evolution and Molecular Drive... 

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