Abstract
Background: One of the most fundamental problems, which remain unsolved, is how entirely new gene (EntNew gene) was produced, which is totally different gene from any previously existing gene. On the other hand, we have proposed GC-NSF(a) hypothesis on formation of EntNew gene/protein, assuming that EntNew gene is generated from non-stop frame on antisense strand of GCrich gene (GC-NSF(a)).
Objective: The objective of this study is to obtain direct evidence clearly supporting the GC-NSF(a) hypothesis through computer analysis of gene/protein databases of GC-rich microbial genomes.
Method: In order to get direct evidence for the hypothesis, every base sequence encoded by GC-rich P. aeruginosa PAO1 genome (GC content=66.6%) was transformed into antisense sequence (GCNSF( a)). NSF(a) is a non-stop frame codon sequence on antisense strand in the reading frame corresponding with gene on sense strand. AAS of every imaginary protein encoded by the GC-NSF(a) was homology-searched against all extant proteins encoded by the same genome. Program version 2.2.30+ of BLASTP in NCBI for computational investigation was used in the homology-search.
Results: From the results, it was found that AAS encoded by GC-NSF(a) of tal gene has sufficient homology with AAS encoded by ftsZ gene. In addition to another result from the P. aeruginosa genome, three cases showing sufficient homology between AAS encoded by GC-NSF(a) and AAS of extant protein were also obtained from the results similarly analyzed with 57 GC-rich microbial genomes.
Conclusion: Thus, we conclude that EntNew gene encoding EntNew protein has been generated from GC-NSF(a), according to the GC-NSF(a) hypothesis.
Keywords: Degeneracy of genetic code, domain formation, GC-NSF(a) hypothesis, origin of gene, origin of protein, protein 0th-order structure.
Graphical Abstract