## Description

This track shows the sequencing quality score (range: 0 to 99) of each base in the assembly. The height of the graph at each position of the track indicates the quality of the base. When zoomed out to a large range, the heights reflect the averaged scores. Scores of 40 or higher reflect high confidence in the sequence (with an error rate of less than 1/10,000); scores of 20 or higher reflect reasonable confidence (of working draft quality).

This track includes quality scores for all chromosomes assembled from whole genome shotgun contigs. Quality scores for chromosomes generated from finished clones (chr21, chrY, and chrY_random) were not available at the time this track was constructed; all scores for these chromosomes were manually set at 98. Chromosome 7 was constructed from both contigs and clones; the quality track for this chromosome contains the contig quality scores, with the 1MB finished region indicated by the manually assigned score of 98. All other scores in this track range between 0 and 97 inclusive.

This track may be configured in a variety of ways to highlight different aspects of the displayed information. Click the Graph configuration help link for an explanation of the configuration options.

## Credits

The quality scores were provided by Joanne Nelson of Washington University St. Louis. The database representation and graphical display code were written by Hiram Clawson.