Dois cientistas da UFSCar apontam a crise de informação da evolução prebiótica

segunda-feira, outubro 29, 2007

Daniel A. M. M. Silvestre e José F. Fontanari fontanari@ifsc.usp.br, dois cientistas brasileiros do Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, 13560-970 São Carlos SP, Brasil publicaram recentemente um excelente artigo Package models and the information crisis of prebiotic evolution [Modelos de pacote e a crise da informação da evolução prebiótica. PDF de 433.50 KB pode ser baixado gratuitamente aqui]

Abstract:

The coexistence between different types of templates has been the choice solution to the information crisis of prebiotic evolution, triggered by the finding that a single RNA-like template cannot carry enough information to code for any useful replicase. In principle, confining d distinct templates of length L in a package or protocell, whose survival depends on the coexistence of the templates it holds in, could resolve this crisis provided that d is made sufficiently large. Here we review the prototypical package model of Niesert et al. (1981) which guarantees the greatest possible region of viability of the protocell population, and show that this model, and hence the entire package approach, does not resolve the information crisis. This is so because to secure survival the total information content of the protocell, Ld, must tend to a constant value that depends only on the spontaneous error rate per nucleotide of the template replication mechanism. As a result, an increase of d must be followed by a decrease of L to ensure the protocell viability, so that the net information gain is null.

Key words: Prebiotic evolution, package models, hypercycles, error threshold, genetic diversity

The coexistence of different types of templates has been the choice solution to the information crisis of prebiotic evolution, triggered by the finding that a single RNA-like template cannot carry enough information to code for any useful replicase. In principle, confining d distinct templates of length L in a package or protocell, whose survival depends on the coexistence of the templates it holds in, could resolve this crisis provided that d is made sufficiently large.

We review the prototypical package model of Niesert et al. (1981) which guarantees the greatest possible region of viability of the protocell population, and show that this model, and hence the entire package approach, does not resolve the information crisis. This is so because to secure survival the total information content of the protocell, Ld, must tend to a constant value that depends only on the spontaneous error rate per nucleotide of the template replication mechanism. As a result, an increase of d must be followed by a decrease of L to ensure the protocell viability, so that the net information gain is null.

Coming up with a coherent scenario to explain the coexistence of distinct templates has proved to be a most difficult endeavor and it may already be time to turn to new approaches to solve the information crisis of prebiotic evolution. We have nothing to offer on this direction.

NOTA BENE:

Conclusão dos pesquisadores

“Coming up with a coherent scenario to explain the coexistence of distinct templates has proved to be a most difficult endeavor and it may already be time to turn to new approaches to solve the information crisis of prebiotic evolution. We have nothing to offer on this direction.”


Silvestre e Fontanari concluem afirmando que talvez seja hora de buscarmos novas abordagens para resolver a crise de informação da evolução prebiótica, e que os evolucionistas ortodoxos não têm nada para oferecer nesta direção. Design Inteligente???

Os teóricos e proponentes da teoria do Design Inteligente têm proposto que certos eventos do universo e do mundo biótico são melhor explicados por causas inteligentes, e que essas causas são empiricamente detectadas.

William Dembski, no seu livro “Design Inference: Eliminating Chance Through Small Probabilities” [Cambridge, Cambridge University, 2001] aborda a questão da informação. Não consta na bibliografia dos autores.