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A unit of genetic length for DNA (or RNA) fragments equal to 1 million nucleotides (roughly equal to 1 cM).


(meg′ă-bās″) [ mega- + base],


1. One million paired nucleotides in a DNA sequence.
2. One million unpaired nucleotides in a single-stranded nucleic acid sequence.
3. Informally, any very large fragment of DNA.


A unit of measurement of the length of a segment of DNA equal to 1,000,000 base pairs. Usually contracted to Mb.

Megabase (Mb)

DNA or RNA of length 106 bases. Used as a unit of length for single-stranded or double-stranded molecules; although Mbp may also be used for the latter.
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BIOSIS is a not-for-profit organization publishing megabases that abstract and index the international literature of the biological, medical, and life sciences.
Simulation experiments indicate that a copy number increase of 50% should be detectable if the region is 2 megabase pairs (Mbp) or larger, and an amplified region (amplicon) of 250 kilobase pairs (kbp) would need a 400% copy number increase to be detectable with metaphase CGH.
DNA amounts in picograms can be converted to megabase pairs (Mbp) by means of the conversion factor of 1 pg = 980 Mbp (Bennett et al.
org) has built a leading megabase of indexed, abstracted citations to the published literature in the field.
Gene identification and DNA sequence analysis in the GC-poor 20 megabase region of human chromosome 21.
And LEXIS-NEXIS may have heralded the end of coverage angst with the relaunch of its LEXIS-NEXIS Universe, offering the entire megabase on the Web at flat-fee pricing.
TruSeq reagents generate uniformly covered sequence from less than a megabase to the entire coding region of the human genome rapidly and economically," said Illumina's Christian Henry, Senior Vice President, General Manager of Life Sciences and Chief Financial Officer.
In addition, electrophoretic karyotyping with pulsed-field gel electrophoresis showed that both isolates had identical patterns, with eight chromosome fragments, one of which was <1 megabase (Mb), indicating that the two morphologically different strains were the same karyotypically.
As for you traditional online services, supermarket search services, database aggregators, and megabase abstracting services, lord knows you have more troubles and tasks than fingers and toes.
Laboratory-grown rice seedlings were irradiated with Westinghouse FS20 lamps (primarily UVB radiation, 290-320 nm) to produce initial CPD levels of ~10 to 60 sites/Mb (Mb, megabase, 1 million bases).
The search services and major megabase database producers do have their giant archived backfiles, but they still depend on the knowledge and skill and training of individual searchers to wrest, carve, squeeze, concoct, and extract the value out of the raw materials in the archives.
In several earlier columns I have suggested that leading sci-tech megabase producers should take on responsibility for building archives and access tools that integrate Net traffic scholarship with its traditional print coverage.