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Genome signature tags

  • US 7,323,306 B2
  • Filed: 03/02/2004
  • Issued: 01/29/2008
  • Est. Priority Date: 04/01/2002
  • Status: Expired due to Fees
First Claim
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1. A method for analyzing the organismic complexity of a sample, comprising:

  • a) providing a sample containing one or more organisms;

    b) isolating the DNA from the organisms in the sample;

    c) contacting the DNA with a fragmenting enzyme, said fragmenting enzyme being a type IT restriction endonuclease, under conditions appropriate for substantially complete digestion of the DNA thereby generating a plurality of DNA fragment species, each having complementary cohesive termini;

    d) incubating the DNA fragment species of step c) with a molar excess of a capture adapter, the capture adapter being a substantially duplex DNA having a portion which is covalently modifiedwith a first member of a specific binding pair and also having one cohesive end compatible with the cohesive termini generated by the fragmenting enzyme of step c), under conditions appropriate for ligating the capture adapter to each of the complementary cohesive termini of the DNA fragment species, thereby generating a plurality of ligation products;

    e) contacting the ligation products of step d) with an anchoring enzyme under conditions for substantially complete digestion of the ligation products, said anchoring enzyme being a restriction endonuclease having a high probability of cleaving a substantial number of DNA fragment species generated in step c) at least one time, thereby generating a plurality of digestion products which have one cohesive terminus generated by the anchoring enzyme and a portion that is covalently modified with a first member of the specific binding pair;

    f) capturing the digestion products of step e) by contacting the digestion products with a solid support having an attached second member of the, specific binding pair;

    g) incubating the solid support and captured digestion products of step f) with a molar excess of a duplex linker having a type IIS restriction enzyme recognition sequence and one cohesive terminus compatible pith termini generated by the anchoring enzyme of step e), under conditions appropriate for ligating one duplex linker to the cohesive termini of the captured digestion products, thereby ligating a recognition sequence for a type ITS restriction enzyme to the captured digestion products;

    h) incubating the ligation product of step g) with the type IIS restriction enzyme, under conditions appropriate for substantially complete digestion thereby releasing the duplex linkers, each having an appended signature tag;

    i) recovering the released duplex linkers and appended signature tags;

    j) incubating the recovered linkers and tags of step i) with a molar excess of an amplification adapter, the amplification adapter having one terminus compatible with the termini of the appended signature tags, the incubation being carried out under conditions appropriate for ligating one amplification adapter to each appended signature tag;

    k) recovering the ligation products of step j);

    l) determining the nucleotide sequence of a statistically. significant number of appended signaturetags to generate a listing of signature tags; and

    ,m) relating the listing, of signature tags of step 1) to DNA sequences in databases to determine the variety and relative numbers of organisms originally present in the sample thereby analyzing the organismic complexity of the sample.

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