## Description

This track shows the location of sites showing transcription over the first 24 hours of D. melanogaster development in two hour increments, measured by a tiling array as described in Manak et al. (2006) (see References). Clustered sites are shown in separate subtracks for each of the twelve timepoints.

## Display Conventions and Configuration

To show only selected subtracks, uncheck the boxes next to the tracks that you wish to hide.

Color differences among the subtracks are arbitrary. They provide a visual cue for distinguishing between the different timepoints.

## Methods

The data were processed into signal and transfrags as described in Cheng et al. (2005) and Kampa et al. (2004). The data from replicate arrays were quantile-normalized and all arrays were scaled to a median array intensity of 25. Within a sliding 101 bp window centered on each probe, an estimate of RNA abundance (signal) was found by calculating the median of all pairwise average PM-MM values, where PM is a perfect match and MM is a mismatch.

## Verification

Samples were hybridized to duplicate arrays (three technical replicates). Transcribed regions (see the Affy Signal track) were generated from the composite signal track by merging genomic positions to which probes are mapped. This merging was based on a 5% false positive rate cutoff in negative bacterial controls, a maximum gap (MaxGap) of 50 base-pairs and minimum run (MinRun) of 90 base-pairs.

## Credits

These data were generated and analyzed by the Tom Gingeras group at Affymetrix.

## References

Please see the Affymetrix Transcriptome site for a project overview and additional references to Affymetrix tiling array publications.

Manak JR, Dike S, Sementchenko V, Kapranov P, Biemar F, Long J, Cheng J, Bell I, Ghosh S, Piccolboni A, Gingeras TR. Biological function of unannotated transcription during the early development of Drosophila melanogaster. Nature Genet. 2006 Oct;38(10):1151-8.

Cheng J, Kapranov P, Drenkow J, Dike S, Brubaker S, Patel S, Long J, Stern D, Tammana H, Helt G, et al. Transcriptional maps of 10 human chromosomes at 5-nucleotide resolution. Science. 2005 May 20;308(5725):1149-54.

Kampa D, Cheng J, Kapranov P, Yamanaka M, Brubaker S, Cawley S, Drenkow J, Piccolboni A, Bekiranov S, Helt G, et al. Novel RNAs identified from an in-depth analysis of the transcriptome of human chromosomes 21 and 22. Genome Res. 2004 Mar;14(3):331-42.