You need proteins to maintain and manage DNA (to replicate and stuff), but you need DNA to assemble the proteins that work on it. In other words, how does DNA self replicate before its replication “technology” exists? So, like the chicken or the egg problem, which came first?
>> DNA first, with RNA as a likely precursor replicator.
DNA could have evolved gradually from a simpler replicator; RNA is a likely candidate, since it can catalyze its own duplication (Jeffares et al. 1998; Leipe et al. 1999; Poole et al. 1998). The RNA itself could have had simpler precursors, such as peptide nucleic acids (Böhler et al. 1995). A deoxyribozyme can both catalyze its own replication and function to cleave RNA -- all without any protein enzymes (Levy and Ellington 2003).
References:
- Böhler, C., P. E. Nielsen, and L. E. Orgel. 1995. Template switching between PNA and RNA oligonucleotides. Nature 376: 578-581. See also: Piccirilli, J. A., 1995. RNA seeks its maker. Nature 376: 548-549.
- Jeffares, D. C., A. M. Poole and D. Penny. 1998. Relics from the RNA world. Journal of Molecular Evolution 46: 18-36.
- Leipe, D. D., L. Aravind, and E. V. Koonin. 1999. Did DNA replication evolve twice independently? Nucleic Acids Research 27: 3389-3401.
- Levy, Matthew and Andrew D. Ellington. 2003. Exponential growth by cross-catalytic cleavage of deoxyribozymogens. Proceedings of the National Academy of Science USA 100(11): 6416-6421.
- Poole, A. M., D. C. Jeffares, and D. Penny. 1998. The path from the RNA world. Journal of Molecular Evolution 46: 1-17.
< But RNA is too unstable.
[need details]
>> It came by Biochemical Predestination.
Chemicals are predestined to attract each other.< But Dean Kenyon begins to original doubt this theory as DNA becomes the only known source of info, NOT proteins’ self attractiveness.
He doubted that proteins can self-assemble.
Amino acids naturally don't have that ability to order themselves.
If amino acids can’t self assemble, then it needs DNA.
- http://en.wikipedia.org/wiki/Dean_H._Kenyon
>> Through natural selection.
< That's a circular argument.
You can't explain how DNA is formed with natural selection because you need DNA to replicate and pass on the information in the first place, hence for natural selection to function.
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