Nontemplate Polymerization of Free Nucleotides Into Genetic Elements by Thermophilic DNA Polymerase in vitro

Abstract

DNA synthesis is the cornerstone of all life forms and is required to replicate and restore the genetic information. Usually, DNA synthesis is carried out only by DNA polymerases semiconservatively to copy preexisting DNA templates. We report here that DNA strands were synthesized ab initio in the absence of any DNA or RNA template by thermophilic DNA polymerases at (a) a constant high temperature (74°C), (b) alternating temperatures (94°C/60°C/74°C), or (c) physiological temperatures (37°C). The majority of the ab initio synthesized DNA represented short sequence blocks, repeated sequences, intergenic spacers, and other unknown genetic elements. These results suggest that novel DNA elements could be synthesized in the absence of a nucleic acid template by thermophilic DNA polymerases in vitro. Biogenesis of genetic information by thermophilic DNA polymerase-mediated nontemplate DNA synthesis may explain the origin of genetic information and could serve as a new way of biosynthesis of genetic information that may have facilitated the evolution of life.

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Keywords:

• DNA polymerase
• DNA synthesis
• nucleic acid biosynthesis
• nontemplate DNA synthesis
• biogenesis and origin of genetic information

Acknowledgments

This research was financially supported in part by the Rockefeller Foundation and Agriculture and Agri-Food Canada grant to D. W. C and a National Institute on Minority Health and Health Disparities (NIMHD) grant to A. C.-U (Research Infrastructure for Minority Institutions, grant no. P20MD002732). We thank Professor Ray Wu at Cornell University, Dr. Ken Armstrong at the Plant Research Center of Agriculture and Agri-Food, Canada, for their critical suggestions and discussions, and Dr. James Prince at California State University, Fresno, for critically reading the manuscript. Finally, we would like to thank an anonymous reviewer for constructive criticism and suggestions.