| CPC C12N 15/1003 (2013.01) [C12N 15/1006 (2013.01); C12Q 1/68 (2013.01); C12Q 1/6834 (2013.01); Y02A 50/30 (2018.01)] | 19 Claims |
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1. A method for enriching short nucleic acid from a nucleic acid composition, which comprises:
(a) contacting cell-free nucleic acid from a substantially cell-free biological composition with a solid phase under an association condition, wherein:
(i) the cell-free nucleic acid comprises short nucleic acid and long nucleic acid,
(ii) the short nucleic acid is 200 base pairs or less,
(iii) the long nucleic acid is larger than 200 base pairs,
(iv) the association condition comprises a salt, and
(v) the association condition does not include polyethylene glycol (PEG), whereby the short nucleic acid and the long nucleic acid associate with the solid phase;
(b) introducing the solid phase from (a) to a dissociation condition that comprises a volume exclusion agent and/or a salt, wherein:
(i) the salt is not a chaotropic salt,
(ii) the short nucleic acid dissociates from the solid phase under the dissociation condition, thereby yielding dissociated nucleic acid, and
(iii) the volume exclusion agent comprises a polyalkyl glycol, dextran, ficoll, polyvinyl pyrrolidone, or combination thereof; and
(c) separating the dissociated nucleic acid from the solid phase by transferring the dissociated nucleic acid to a vessel that does not contain the solid phase used in (b) or by transferring the solid phase used in (b) to a vessel that does not contain the dissociated nucleic acid, thereby enriching the short nucleic acid relative to the long nucleic acid in the dissociated nucleic acid compared to the cell-free nucleic acid in (a).
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