MBIO 4440 Lecture Notes - Lecture 11: New England Biolabs, Molecular-Weight Size Marker, Deoxyribonuclease I
13 Feb 2019
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Document Summary
Once the dna is isolated, achieving the right size of the target dna fragments in the final library is a key parameter. Three approaches are available to fragment nucleic acid chains: physical, enzymatic, and chemical. Dna fragmentation can be done by physical methods such as sonication. A covaris instrument is typically used for ngs projects. With a covaris sonicator, dna fragments in the 100-5,000 bp range can be obtained. Enzymatic methods include digestion by dnase i or fragmentase, a two enzyme mix (new england biolabs, ipswich ma). Dna is illumina"s nextera tagmentation technology (illumina, san diego, ca) in which a transposase enzyme simultaneously fragments and inserts adapter sequences into dsdna. (cuts dna and adds transposon with an adapter) Chemical fragmentation is typically reserved for the breakup of long rna fragments. This is typically performed through the heat digestion of rna with a divalent metal cation (magnesium or zinc).
