Modified nucleic acid probes

1. A method of detecting a mutation or polymorphism in a target oligonucleotide, comprising:

attaching a first oligonucleotide analogue probe set to the array, wherein the probes of said first analogue probe set comprise at least one sugar moiety having a modified 2′ position, wherein said first probe set comprise at least one interrogation position, and wherein the oligonucleotides of said first probe set comprise a sequence which is perfectly complementary to the target oligonucleotide sequence;

attaching a second oligonucleotide analogue probe set to the array, wherein the probes of said second analogue probe set comprise at least one sugar moiety having a modified 2′ position, wherein said second probe set is identical to the first probe set, except that the second probe set comprises a different nucleotide analogue than the first probe set at least one interrogation position;

hybridizing the target oligonucleotide to the array; and

detecting which probe set is hybridized with the target oligonucleotide, thereby detecting the mutation or polymorphism in the target oligonucleotide.

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

attaching a third oligonucleotide analogue probe set to the array, wherein said third probe set is identical to the first and second probe sets, except that the third probe set comprises a nucleotide analogue at the at least one interrogation position which is different than the nucleotide analogue present at the same position in the first or second probe set and wherein said nucleotide analogue comprises a sugar moiety having a 2′-O-alkyl group.

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

attaching a fourth oligonucleotide analogue probe set to the array, wherein said fourth probe set is identical to the first, second and third probe sets, except that the fourth probe set comprises a nucleotide analogue at the at least one interrogation position which is different than the nucleotide analogue present at the same position in the first, second or third probe set and wherein said nucleotide analogue comprises a sugar moiety having a 2′-O-alkyl group.

4. The method according to claim 3 , further comprising:

attaching a fifth oligonucleotide analogue probe set to the array, wherein said fifth probe set is identical to the first, second, third and fourth probe sets, except that the fifth probe set comprises a nucleotide analogue at the at least one interrogation position which is different than the nucleotide analogue present at the same position in the first, second, third or fourth probe set and wherein said nucleotide analogue comprises a sugar moiety having a 2′-O-alkyl group.

5. The method according to claim 1 , wherein the target oligonucleotide is a polymerase chain reaction (PCR) amplicon which comprises one or more nucleotide analogues wherein said nucleotide analogue comprises a sugar moiety having a 2′-O-alkyl group.

6. The method according to claim 1 , wherein the probe sets comprise a segment of sequence which is perfectly complementary to the target sequence, and wherein the segment is flanked by a leading or trailing sequence segment which is not complementary to the target sequence.

7. The method according to claim 1 , wherein the probe sets comprise a segment of sequence which is perfectly complementary to the target sequence, and wherein the segment is flanked by both a leading and a trailing sequence segment which are not complementary to the target sequence.

8. The method according to claim 1 , wherein the at least one interrogation position of the second probe set is at a different sequence position than in the first probe set.

9. The method according to claim 1 , wherein the probe sets are immobilized on the array at a density of at least 100 probes/cm 2 .

10. The method according to claim 1 , wherein the probe sets are immobilized on the array at a density of at least 1,000 probes/cm 2 .

11. The method according to claim 1 , wherein the probe sets are immobilized on the array at a density of at least 10,000 probes/cm 2 .

12. A method for analyzing interactions between a target nucleic acid and an oligonucleotide probe, comprising:

(a) providing a microarray comprising at least 100 different sequence oligonucleotide probes coupled to a solid support, wherein a plurality of the oligonucleotide probes comprise at least one sugar moiety having a modification, wherein said modification comprises a 2′-O-alkyl group;

(b) providing a sample comprising one or more target nucleic acids;

(c) hybridizing the sample to the microarray under hybridization conditions such that said target nucleic acids bind to said oligonucleotide probes to form target:probe duplexes; and

(d) detecting the presence of the target:probe duplexes, wherein the presence of a target:probe duplex indicates the presence of a target in the sample.

13. The method of claim 12 , wherein the target is RNA.

14. The method of claim 12 , wherein the target nucleic acid is amplified prior to the hybridizing step.

15. The method of claim 12 , wherein the plurality of oligonucleotide probes is synthesized on the solid support by light-directed synthesis.

16. The method of claim 12 , wherein the 2′-O-alkly group is a 2′-O-methyl.

17. The method of claim 12 , wherein the oligonucleotide probes are between 8 and 15 nucleotides in length.

18. The method of claim 12 , wherein the oligonucleotide probes are between 5 and 20 nucleotides in length.

19. The method according to claim 12 , wherein the probe sets are immobilized on the array at a density of at least 100 probes/cm 2 .

20. The method according to claim 12 , wherein the probe sets are immobilized on the array at a density of at least 1,000 probes/cm 2 .

21. The method according to claim 12 , wherein the probe sets are immobilized on the array at a density of at least 10,000 probes/cm 2 .

22. The method of claim 1 wherein said sugar moiety having a modified 2′ position comprises a 2′-O-alkyl group.

23. The method of claim 1 wherein said sugar moiety having a modified 2′ position comprises a 2′-O-methyl group.