Multiplex nucleic acid detection methods and systems
The present invention relates to methods and systems for single molecule based clonal amplification and subsequent detection of nucleic acid molecules, and particularly to the determination of SNPs, mutations, and to the diagnosis of diseases associated with the changes of these nucleic acid molecules.
1. A method for determining the identity code of identity sequence tags, comprising the steps of:
(a) immobilizing a plurality of analyte molecules on a surface, wherein each analyte molecule comprises an identity sequence (IS) tag that is accessible to a probe for hybridization, and wherein the IS tag is less than or equal to 10 nucleotides in length;
(b) hybridizing a pair of labeled IS probes (LISPs) from a pool of LISPs with said IS tags at base interrogation positions, thereby said pair of LISPs are juxtaposed, wherein each said LISP comprises: (i) a sequence complimentary to the IS tag sequence it hybridizes to, and (ii) a detectable label associated with a designated base at said base interrogation positions, and wherein there are two sets of the LISPs in each pool of LISPs, with one set being the 3′ labeled IS probes (3′-LISPs) that comprise 5′ phosphate groups and 3′ detectable labels, and the other set being the 5′ labeled IS probes (5′-LISPs) that comprise 5′ detectable labels and 3′ hydroxyl groups;
(c) performing a paired-probe ligation for ligating said pair of juxtaposed LISPs;
(d) detecting the presence of said detectable labels on said ligated pair of LISPs on said IS tags of said analyte molecules, and elucidating the base composition at said base interrogation positions of said IS tags according to the detectable label combination of said ligated pair of LISPs, wherein two specified base positions on said IS tags and one on each side of said paired probes are interrogated by mixing two detectable labels;
(e) denaturing said ligated pair of LISPs from said analyte molecule;
(f) repeating steps (b) to (e) until all bases of said base interrogation positions in said IS tags are interrogated without duplication and all base composition of said IS tags are elucidated; and
(g) determining the ID codes of said IS tags on said analyte molecules by comparing said base composition to designated ID codes, wherein 10^n (or 10 n ) kinds of the base combinations are distinguished in n times of the paired-probe ligation.
2. The method of claim 1 , wherein the said detectable labels on said ligated pair of LISPs resulting from each paired-probe ligation are identical or different detectable labels.
3. The method of claim 1 , wherein there are four different detectable labels on the two sets of the LISPs with each detectable label representing a designated base (A, C, G, T) at said base interrogation positions, and wherein all probes needed for all possible base combinations at said base interrogation positions are included in each pool of LISPs.
4. The method of claim 1 , wherein a different pool of LISPs is used in each ligation cycle, and wherein different base positions on said IS tags are sequentially interrogated in each ligation cycle.
5. The method of claim 1 , wherein the labels on said LISP comprises fluorescent dyes, electrochemical labels, or nanoparticles.
6. The method of claim 1 , wherein said base interrogation positions are within 5 bases from the ligation point of each LISP to maintain a base recognition specificity in said paired-probe ligation.
7. The method of claim 1 , wherein said base interrogation positions are within 3 bases from a ligation point of each LISP to maintain a base recognition specificity in said paired-probe ligation.