Searching for Microbes and DNA in Ancient Halite

Abstract

David Hume (1711–1767) is credited with coining the phrase “A wise man, therefore, proportions his belief to the evidence.” This was later brought to a more modern understanding by Marcello Truzzi as “An extraordinary claim requires extraordinary proof” (Truzzi 1978). Certainly such an admonition should be considered by any and all scientists attempting to carry out research on ancient living microbes or DNA. Such supporting evidence should include several factors with publications and reports often seeming to be more about the evidence than about the discovery. The key bits of supporting information described here range from the overall geological pedigree of the formation and the individual sample, the sterilization assurance levels and even the design of the laboratory in which the work occurred. This chapter outlines how to establish these various types of evidence in order to support claims that any isolate or DNA sequence is as old as the crystal in which it was found. Adherence to these ideas will never make claims of ancient life immediately accepted. However, experience has shown that having these various bits of information on hand will at least make the debate more likely to have a positive outcome.