NUCLEIC ACID ANALYSIS BY RANDOM MIXTURES OF NON-OVERLAPPING FRAGMENTS
The invention provides methods and kits for ordering sequence information derived from one or more target polynucleotides. In one aspect, one or more tiers or levels of fragmentation and aliquoting are generated, after which sequence information is obtained from fragments in a final level or tier. Each fragment in such final tier is from a particular aliquot, which, in turn, is from a particular aliquot of a prior tier, and so on. For every fragment of an aliquot in the final tier, the aliquots from which it was derived at every prior tier is known, or can be discerned. Thus, identical sequences from overlapping fragments from different aliquots can be distinguished and grouped as being derived from the same or different fragments from prior tiers. When the fragments in the final tier are sequenced, overlapping sequence regions of fragments in different aliquots are used to register the fragments so that non-overlapping regions are ordered. In one aspect, this process is carried out in a hierarchical fashion until the one or more target polynucleotides are characterized, e.g. by their nucleic acid sequences, or by an ordering of sequence segments, or by an ordering of single nucleotide polymorphisms (SNPs), or the like.
1 . A method of sequencing one or more target polynucleotides, the method comprising the steps of:
fragmenting a predetermined coverage amount of the one or more target polynucleotides to form a population containing overlapping first-sized fragments of the one or more target polynucleotides;
forming a number of separate mixtures from the population of first-sized fragments;
fragmenting the first-sized fragments in the separate mixtures to form populations of second-sized fragments;
attaching oligonucleotide tags to the second-sized fragments to produce tagged fragments, wherein each oligonucleotide tag identifies the mixture of origin of the respective tagged fragment;
sequencing at least a portion of a plurality of the tagged fragments in at least some of the mixtures to obtain sequence information; and
obtaining complete or partial nucleotide sequences of the one or more target polynucleotides by ordering at least a portion of the sequence information, wherein such ordering comprises determining the mixture of origin of fragments from which the sequence information was obtained.