An Overview of Cultural, Molecular and Metagenomic Techniques in Description of Microbial Diversity

Traditional microbiology based on the culture of microorganisms has been the mainstay of microbiology for over a century and has contributed immensely to what we now know about the harmful and beneficial roles of microorganisms. However, it has a number of limitations that has hampered the full utilization of the non-culturable majority in various ecosystems. Metagenomics is a technique that bypasses the need to culture microorganisms from various samples. Unarguably, it is one of the few powerful techniques that have revolutionized every aspect of molecular biology, microbiology, microbial ecology and even beyond. Although still in its infancy, metagenomics have far reaching applications already in medicine and health care, biotechnology, environmental microbiology, bioprospecting for new products of biological origin, discovery of functional genes, evolution, to mention just a few. The various steps involved in metagenomics from sampling to sequencing have all been shown to affect the overall diversity of the sampled ecosystem. An ideal methodology should be one that produces a fair representation of the community sampled. The rapid progress in sequencing technologies has forced its cost down per sample. This has lead to a drastic increase in the number of research projects using sequencing technologies, and databases that can store, analyse and allow retrieval of metagenomics data. With this pace of growth, we will certainly see many putative genes, proteins and pathways come alive, and also witness a number of paradigm shifts in some key concepts in traditional microbiology like taxonomy and microbial physiology.