Just how Lamarckian is CRISPR-Cas immunity: the continuum of evolvability mechanisms
Eugene V. Koonin Email author and Yuri I. Wolf
Biology Direct201611:9
© Koonin and Wolf. 2016
Received: 31 December 2015Accepted: 16 February 2016Published: 24 February 2016
Open Peer Review reports
Source/Fonte: YouTube
Abstract
The CRISPR-Cas system of prokaryotic adaptive immunity displays features of a mechanism for directional, Lamarckian evolution. Indeed, this system modifies a specific locus in a bacterial or archaeal genome by inserting a piece of foreign DNA into a CRISPR array which results in acquired, heritable resistance to the cognate selfish element. A key element of the Lamarckian scheme is the specificity and directionality of the mutational process whereby an environmental cue causes only mutations that provide specific adaptations to the original challenge. In the case of adaptive immunity, the specificity of mutations is equivalent to self-nonself discrimination. Recent studies on the CRISPR mechanism have shown that the levels of discrimination can substantially differ such that in some CRISPR-Cas variants incorporation of DNA is random whereas discrimination occurs by selection of cells that carry cognate inserts. In other systems, a higher level of specificity appears to be achieved via specialized mechanisms. These findings emphasize the continuity between random and directed mutations and the critical importance of evolved mechanisms that govern the mutational process.
Reviewers: This article has been reviewed by Yitzhak Pilpel, Martijn Huynen, and Bojan Zagrovic.
Keywords
CRISPR-Cas Self-nonself discrimination Lamarckian evolution Darwinian evolution DNA repair
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PERGUNTA DESTE BLOGGER:
Quer dizer então que o fato, Fato, FATO da evolução não é assim uma Brastemp darwinista? E que o espectro do fantasma de Lamarck ronda a casa de Down? Calma! A nova teoria geral da evolução - a SÍNTESE EVOLUTIVA AMPLIADA/EXTENDIDA já incorporou aspectos neolamarckistas, e o próprio Darwin na sexta edição do Origem das Espécies foi muito mais lamarckista do que Lamarck.
Quando este blogger dizia "Lamarck redivivus", alguns cientistas da Nomenklatura científica tupiniquim e a Galera dos meninos e meninas de Darwin riam litros desse "simples professorzinho do ensino médio" (SQN, desde 2008 ele é Mestre em História da Ciência pela PUC-São Paulo). Rindo está este blogger desde o início!!!
O bom de tudo isso, é ver evolucionistas honestos como Koonin e Wolf vindicando este blogger!
Fui, celebrar Lamarck, pois Darwin kaput desde 1859!!!
Fui, celebrar Lamarck, pois Darwin kaput desde 1859!!!
