The Archaea domain: Exploring historical and contemporary perspectives with in silico primer coverage analysis for future research in Dentistry.

ABSTRACT

OBJECTIVE: The complete picture of how the human microbiome interacts with its host is still largely unknown, particularly concerning microorganisms beyond bacteria. Although existing in very low abundance and not directly linked to causing diseases, archaea have been detected in various sites of the human body, including the gastrointestinal tract, oral cavity, skin, eyes, respiratory and urinary systems. But what exactly are these microorganisms? In the early 1990 s, archaea were classified as a distinct domain of life, sharing a more recent common ancestor with eukaryotes than with bacteria. While archaea's presence and potential significance in Dentistry remain under-recognized, there are concerns that they may contribute to oral dysbiosis. However, detecting archaea in oral samples presents challenges, including difficulties in culturing, the selection of DNA extraction methods, primer design, bioinformatic analysis, and databases. DESIGN: This is a comprehensive review on the oral archaeome, presenting an in-depth in silico analysis of various primers commonly used for detecting archaea in human body sites. RESULTS: Among several primer pairs used for detecting archaea in human samples across the literature, only one specifically designed for detecting methanogenic archaea in stool samples, exhibited exceptional coverage levels for the domain and various archaea phyla. CONCLUSIONS: Our in silico analysis underscores the need for designing new primers targeting not only methanogenic archaea but also nanoarchaeal and thaumarchaeota groups to gain a comprehensive understanding of the archaeal oral community. By doing so, researchers can pave the way for further advancements in the field of oral archaeome research.