Metagenome Analysis Software - MEGAN (a??MEtaGenome ANalyzera??) is a new computer program that allows laptop analysis of large metagenomic datasets. In a preprocessing step, the set of DNA reads (or contigs) is compared against databases of known sequences using BLAST or another comparison tool. MEGAN can then be used to compute and interactively explore the taxonomical content of the dataset, employing the NCBI taxonomy to summarize and order the results.