Metagenomics applies the knowledge that all creatures contain nucleic acids; therefore, organisms do not have to be cultured, but can be identified by a particular gene sequence, or its derived protein, or even metabolite. The term “meta” is derived from meta-analysis, which is the process of statistically combining separate analyses. Metagenomics uses the same approach as genomics. It differs in the nature of the sample. Genomics focuses on a single organism, whereas metagenomics deals with multiple organisms, “gene creatures” (i.e., viruses, viroids, plasmids, etc.) and/or free DNA. Though rarely mentioned, many habitats contain relatively large fractions of DNA that is free rather than inside organisms. Metagenomic researchers isolate DNA and RNA from a sample of the habitat, such as soil or sea-water, without isolating or identifying individual organisms. The DNA or RNA is then analyzed by various genomic procedures, including shotgun DNA sequencing, PCR, RT-PCR, and so forth.