Tiling arrays are a subtype of microarray chips where the probes are designed to cover a region of the genome, hence the term "tiling" array. They function on a similar principle to traditional microarrays where labelled target molecules are hybridised to unlabelled probes on a fixed solid surface.
While traditional DNA microarrays are designed to look at gene expression of a few probes for a known or predicted gene, tiling arrays may characterise previously unidentified genes and provide an unbiased look at gene expression similar to CAGE.
The number of features on a single array can range from 10,000 to greater than 6,000,000, with each feature containing millions of copies of one probe. Thus depending on the probe lengths and spacing, different degrees of resolution can be achieved.
While tiling arrays have been used for individual gene expression analyses, they have been used for transcriptome mapping, ChIP-chip, MeDIP-chip and DNase Chip studies.