Stable isotope probing (SIP) is a technique that is used to identify the microorganisms in environmental samples that use a particular growth substrate. The method relies on the incorporation of a substrate that is highly enriched in a stable isotope, such as 13C, and the identification of active microorganisms by the selective recovery and analysis of isotope-enriched cellular components. DNA and rRNA are the most informative taxonomic biomarkers. The future holds great promise for SIP, particularly when combined with other emerging technologies such as microarrays and metagenomics.
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