Analysis of methylation using nucleic acid arrays
Arrays for genome-wide analysis of methylation are disclosed. In a preferred aspect arrays comprising a plurality of probes complementary to a plurality of identified CpG islands in the human, mouse and rat genome are disclosed. The arrays may be used to detect methylation within CpG islands in samples from human, mouse and rat genomes.
1. An array consisting of a plurality of experimental probes each consisting of a different sequence from SEQ ID NO. 1-222,822.
2. The array of claim 1 further consisting of each of the sequences in SEQ ID NO. 1-222,822, wherein each sequence is present in a different feature of the array.
3. An array of probes consisting of:
more than 250,000 different experimental probe features, wherein
(a) each experimental probe feature comprises a plurality of copies of a nucleic acid probe that is different in sequence from the probes of every other feature of the array;
(b) each probe feature is at a known or determinable location in the array; and
(c) at least 90% of the probe features contain full length probes that are perfectly complementary to a CpG island, wherein a CpG island is a genomic region that is at least 200 bases and has a GC content of at least 50% over its length.
4. The array of claim 3 wherein the full length probes are between 20 and 100 bases in length and are complementary to human, mouse and rat genomic sequences.
5. The array of claim 3 further comprising a plurality of control features.
6. The array of claim 5 wherein the control features comprise one or more types of control features selected from the group of control feature types comprising:
GC content matched anti-genomic controls, bacterial genome controls, Arabidopsis genome controls, Pseudomonas genome controls;
18S rRNA gene controls, 28S rRNA gene controls; and
probes to one or more genes that are known to be regulated by methylation.
7. The array of claim 3 wherein each probe is between 20 and 100 bases, wherein the array comprises at least 300,000 probes and wherein at least 80% of the probes comprise at least one CG dinucleotide.
8. The array of claim 7 wherein at least 50% of the probes comprise at least two CG dinucleotides.
9. The array of claim 7 wherein at least 20% of the probes comprise at least three CG dinucleotides.