Metagenomics can be defined as the study of the metagenome, which is collective genome of microorganisms. The microorganisms are collected from an environmental samples and the studies are conducted to provide information on the microbial diversity and ecology of a specific environment.
Bioinformatics is an amalgamation of biology and information technology, which uses software to link biological data with techniques for information storage, distribution and analysis to support multiple areas of scientific research, including biomedicine.
The study of heritable changes in gene expression that do not involve changes to the underlying DNA sequence is known as epigenetics.