The concept of metagenome was proposed by Handelsman in 1998. It is the sum of DNA in a specific circumstance. Metagenomics is the research about the genome of micropopulation in the circumstance. It studies the microbial diversity, microbial population, evolutionary relationship, and its relationship with circumstance by structure functional gene screening and sequencing analysis. This can improve the use of microbial resources and become a gene bank of medical research and biotechnology research.
The Basic Technology
One is the genome libraries construction. This technology inherits the basic theory and technology of molecular cloning, and adjusts according to the characteristics of sample and the purpose of this construction. Another is the metagenomic library screening. The methods include the function-based screening, sequence based screening and substrate-induced gene expression screening method. Besides, sequencing analysis is also important for metagenomics. With the development of next generation sequencing, the sequencing analysis of metagenomics has changed a lot. The traditional one is the 16s rna sequencing. The 16s rna sequencing can provide enough information, but it still can not provide help for comprehensive analysis. But now, the whole genome sequencing in the circumstance can be analyzed by scientists, which provides a full-scale data base to the metagenomic research.
The Application of Metagenomics
New gene Discovery
The research about metagenomics can be used to find gene expression of new species. For example, Venter made a genome libraries construction of microflora in Sargasoo Sea in 2004, and found much information of species diversity, providing evidence and research source for marine ecology.
Microbial Phylogeny Study
The conception of Environmental biological metagenome makes researchers realize that they can study microbial phylogeny based on the genetic levels. They can extract DNA of the environment, get rDNA by method like PCR, and do phylogenetic analysis after sequencing. This let us have a clear understanding on uncultured microbes.
Research on Biodegradation
The rapid development of industry and the development and usage of resource lead to a great problem of pollution. The microorganism has the characteristic of high-flexibility to the environment. Knowing the reason of this high-flexibility can help us know more about the relationship between environment and microorganism. It also contributes a lot to the research about pollution treatment with microorganism.
The research about metagenomics can not only be used to development of new medicine, but also to the treatment of pollution. Besides, the construction of cDNA library is also an important part of metagenomic research. With the development of technology, the application will become more widely in the future.