By using a concept similar to the statistical concept of meta-analysis, Handelsman et al. coined the term "Metagenomics," which refers to the genomic analysis of a population of microorganisms. Metagenomics is also called as environmental genomics or community metagenomics it is the field to study microbial community in the natural sample like soil, ocean, river, plants, animals, humans etc. With the advent of next generation sequencing techniques and capability of high-end sophisticated software and tools it is possible to analysed mixed population of genomes.