Monday, June 11, 2007

A Minimal Cell

An article at Science Week entitled ORIGIN OF LIFE: IN SEARCH OF THE SIMPLEST CELL, discusses different approaches to determining the nature of the simplest possible cell. The following paragraph is quoted from the article (in red):

"In investigating the origin of life and the simplest possible life forms, one needs to enquire about the composition and working of a minimal cell that has some form of metabolism, genetic replication from a template, and boundary (membrane) production."

Mechanisms able to maintain the integrity of a genome could be added to the above. Cellular functions with energy requirements need to be accounted for and the alluded to functions and structures are all multi-component in nature. The template would have to be ordered to enable both cellular replication and the synthesis of biomolecules. More from the same source:

"A top-down approach will not take us quite to the bottom, to the minimal possible cells in chemical terms. All putative cells, however small, will have a genetic code and a means of transcribing and translating that code. Given the complexity of this system, it is difficult to believe, either logically or historically, that the simplest living chemical system could have had these components."

It is difficult to believe yet the belief persists that incremental pathways to an initial replicating cell existed in the absence of a teleological cause. If data indicates that the simplest cells require scores of genes, a genetic code by which they function and transcribing and translating mechanisms then there is a biological canyon to traverse without mechanisms that allow for change. Gene duplications require a functional genome which in turn is dependent on the existence of a complex of genes. The theoretical mechanism by which genes are generated calls for preexisting genomic complexity. That does not bode well for opponents of intelligent design.

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