Cloning the Metagenome to Access the Biodiversity of...

Introduction Being the essential part of earth’s microbiota and their involvement in chemical, physical and biological transformations, bacteria are considered as a very important group of microorganisms. Those bacteria which cannot be grown easily on artificial nutrient media are referred as unculturables. The evidence for the presence of yet to be cultivated bacteria came from the molecular data. The capability to obtain DNA sequence information from an environmental sample by PCR manipulations and direct sequencing allowed identification of these phylogenetically important groups. When a sample is collected from environment, the total number of bacterial cells within sample is extremely high, which is not appropriate for isolation of†¦show more content†¦Signaling molecules present only within the natural habitat are thought to be essential for the growth of many bacteria. In the absence of these beneficial interactions and signals, some bacteria may struggle to grow in artific ial culture and may be faced with an unfamiliar environment devoid of essential factors (Nichols et al, 2008). Significant efforts have been made in recent years to devise culturing methods for unculturable bacteria. If suitable culture conditions are provided it is possible to cultivate them in the laboratory. These culture techniques include the use of extinction culturing technique with low nutrient media (Button et al, 1998), use of a diffusion chamber that allowed the passage of substances from the natural environment, use of community interactions and cell–cell communication (Dinsdale et al, 2008), use of dilute nutrient media (Hoff et al, 2008) and the use of combinations of techniques (Nichols et al, 2008). The difficulties of cultivating the unculturable bacteria collected from the specific environmental niche are circumvented today by cloning the metagenome in suitable vectors. The term metagenomics is derived from the statistical concept of meta-analysis (the proce ss of statistically combining separate analysis) and genomics (the comprehensive analysis of an organism’s genetic material). The study of metagenomics involves the manipulation of genetic material, recovered directly