Question

What is metagenomics? How does it differ from genomic analysis? List one area where metagenomic analysis has been important.

Answer 1

Metagenomics is a molecular tool used to analyse DNA acquired from environmental samples, in order to study the community of microorganisms present, without the necessity of obtaining pure cultures.Functional metagenomics allows high resolution genomic analysis of unculturable microbes and correlation of the genomes with particular functions in the environment.

Metagenomics deals with the isolation of genetic material directly recovered from environmental samples. Metagenomics as an approach has emerged over the past two decades to elucidate a host of microbial communities inhabiting a specific niche with the goal of understanding their genetic diversity, population structure, and ecological role played by them.

How does it differ from genomic analysis

Genomic analysis is the identification, measurement or comparison of genomic features such as DNA sequence, structural variation, gene expression, or regulatory and functional element annotation at a genomic scale. Methods for genomic analysis typically require high-throughput sequencing or microarray hybridization and bioinformatics. whereas Metagenomics represent a new approach in a genomic analysis. This method accesses the potential reservoir of novel genes in soil. To explore this reservoir, DNA from an environmental sample is extracted, cloned into an appropriate vector, and transformed into competent E. coli cells. The resulting transformants in metagenomic libraries are screened for novel physiological, metabolic, and genetic features. Although time-consuming and labor-intensive, metagenomic is the most powerful environmental approach that offers possibilities to discover novel genes and novel biomolecules through the expression of genes from uncultivated and unknown bacteria in recipient host cell.

List one area where metagenomic analysis has been important.

Metagenomic approaches are often applied in two ways: targeted metagenomics or shotgun metagenomics. In targeted metagenomics or microbiomics, the diversity of a single gene is probed to identify the full complement sequences of a particular gene in an environment and it is most often employed to investigate both the phylogenetic diversity and relative abundance of a particular gene in a sample (Techtmann and Hazen, 2016). This approach is regularly used to investigate the diversity of small subunit rRNA sequences (16S/18S rRNA) in a sample. Microbial ecologists routinely use small subunit rRNA sequencing to understand the taxonomic diversity of an environment. It can also be applied as a tool to investigate the impact of environmental contaminants in altering microbial community structure.

In shotgun metagenomics, the total genomic complement of an environmental community is probed through genomic sequencing.t is a powerful technique where the functional potential of a microbial community can be identified but it is limited by the depth of sequencing.