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In metagenomics, binning is the process of grouping reads or contigs and assigning them to operational taxonomic units. Binning methods can be based on either compositional features or alignment (similarity), or both. == Introduction == Metagenomic samples can contain reads from a huge number of organisms. For example, in a single gram of soil, there can be up to 18000 different types of organisms, each with its own genome. Metagenomic studies sample DNA from the whole community, and make it available as nucleotide sequences of certain length. In most cases, the incomplete nature of the obtained sequences makes it hard to assemble individual genes,〔 〕 much less recovering the full genomes of each organism. Thus, binning techniques represent a "best effort" to identify reads or contigs with certain groups of organisms designated as operational taxonomic units (OTUs). The first studies that sampled DNA from multiple organisms used specific genes to assess diversity and origin of each sample. These marker genes had been previously sequenced from clonal cultures from known organisms, so, whenever one of such genes appeared in a read or contig from the metagenomic sample that read could be assigned to a known species or to the OTU of that species. The problem with this method was that only a tiny fraction of the sequences carried a marker gene, leaving most of the data unassigned. Modern binning techniques use both previously available information independent from the sample and intrinsic information present in the sample. Depending on the diversity and complexity of the sample, their degree of success vary: in some cases they can resolve the sequences up to individual species, while in some others the sequences are identified at best with very broad taxonomic groups. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Binning (Metagenomics)」の詳細全文を読む スポンサード リンク
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