Combinatorial decoding of random nucleic acid arrays

1. A method of determining the location of a decoding sequence on an array composition, said method comprising:

a) providing an array composition comprising:

i) a substrate with a surface comprising discrete sites; and

ii) a population of microspheres comprising at least a first and a second subpopulation distributed on said discrete sites, wherein each subpopulation comprises identifier nucleic acid sequences comprising:

1) the same primer sequence; and

2) a different decoding sequence adjacent to said primer sequence;

wherein said microspheres are distributed on said surface; and

b) providing a first set of combinatorial decoding probes comprising a priming sequence complementary to said primer sequence, a variable sequence, and at least one decoding nucleotide included in said variable sequence that will basepair with at least one nucleotide of at least one of said decoding sequences, wherein said first set comprises different subsets of combinatorial decoding probes, each subset having the same decoding nucleotide and a first label specific to said same decoding nucleotide; and

c) adding to said array composition a subset of said first set of combinatorial decoding probes and detecting the presence of said first label, thereby determining the location of said decoding sequence on said array composition.

2. The method according to claim 1 , further comprising:

d) providing a second set of combinatorial decoding probes comprising said priming sequence complementary to said primer sequence, said variable sequence and at least one decoding nucleotide included in said variable sequence that will basepair with at least one nucleotide of at least one of said decoding sequences at a position that is different from the position that basepairs with said decoding nucleotide of said first set of combinatorial decoding probes, wherein said second set comprises different subsets of combinatorial decoding probes, each subset having the same decoding nucleotide and a second label specific to said same decoding nucleotide; and

e) adding to said array composition a subset of said second set of combinatorial decoding probes and detecting the presence of said second label.

3. The method of claim 2 , wherein said population of microspheres is randomly distributed on said discrete sites.

4. The method of claim 2 , wherein said identifier nucleic acid sequence comprises genomic DNA.

5. The method of claim 2 , wherein said identifier nucleic acid sequence is prepared by an amplification technique.

6. The method of claim 2 , wherein said first set of combinatorial decoding probes comprises four subsets.

7. The method of claim 2 , wherein nucleotides in said variable sequence comprise universal bases.

8. The method of claim 2 , wherein at each variable sequence nucleotide position, all possible naturally occurring nucleotides are represented in at least one decoding sequence of said first set of decoding sequences.

9. The method of claim 2 , wherein said decoding nucleotide is an internal nucleotide of said variable sequence.

10. The method of claim 2 , wherein said decoding nucleotide is a terminal nucleotide of said variable sequence.

11. The method of claim 2 , wherein at each variable sequence nucleotide position, all possible naturally occurring nucleotides are represented in at least one decoding sequence of said second set of decoding sequences.

12. A method of determining the location of a decoding sequence on an array surface, said method comprising:

a) providing at least a first and a second subpopulation of identifier nucleic acid sequences distributed on said surface, said identifier nucleic acid sequences comprising the same primer sequence and a different decoding sequence adjacent to said primer sequence;

b) providing a first set of combinatorial decoding probes comprising a priming sequence complementary to said primer sequence, a variable sequence and at least one decoding nucleotide included in said variable sequence that will basepair with at least one nucleotide of at least one of said decoding sequences, wherein said first set comprises different subsets of combinatorial decoding probes, each subset having the same decoding nucleotide; and

c) adding to said array composition a subset of said first set of combinatorial decoding probes and determining the location of said decoding sequence on said array composition.

13. The method according to claim 12 , further comprising:

d) providing a second set of combinatorial decoding probes comprising said priming sequence complementary to said primer sequence, said variable sequence and at least one decoding nucleotide included in said variable sequence that will basepair with at least one nucleotide of at least one of said decoding sequences at a position that is different from the position that basepairs with said decoding nucleotide of said first set of combinatorial decoding probes, wherein said second set comprises different subsets of combinatorial decoding probes, each subset having the same decoding nucleotide; and

e) adding to said array composition a subset of said second set of combinatorial decoding probes.

14. The method of claim 13 , wherein said identifier nucleic acid sequence comprises genomic DNA.

15. The method of claim 13 , wherein said identifier nucleic acid sequence is prepared by an amplification technique.

16. The method of claim 13 , wherein said first set of combinatorial decoding probes comprises four subsets.

17. The method of claim 13 , wherein nucleotides in said variable sequence comprise universal bases.

18. The method of claim 13 , wherein at each variable sequence nucleotide position, all possible naturally occurring nucleotides are represented in at least one decoding sequence of said first set of decoding sequences.

19. The method of claim 13 , wherein said decoding nucleotide is an internal nucleotide of said variable sequence.

20. The method of claim 13 , wherein said decoding nucleotide is a terminal nucleotide of said variable sequence.

21. The method of claim 13 , wherein at each variable sequence nucleotide position, all possible naturally occurring nucleotides are represented in at least one decoding sequence of said second set of decoding sequences.