## Description

Bacterial artificial chromosomes (BACs) are a key part of many large scale sequencing projects. A BAC typically consists of 25 - 350 kb of DNA. During the early phase of a sequencing project, it is common to sequence a single read (approximately 500 bases) off each end of a large number of BACs. Later on in the project, these BAC end reads can be mapped to the genome sequence.

This track shows these mappings in cases where both ends could be mapped. These BAC end pairs can be useful for validating the assembly over relatively long ranges. In some cases, the BACs are useful biological reagents. This track can also be used for determining which BAC contains a given gene, useful information for certain wet lab experiments.

A valid pair of BAC end sequences must be at least 25 kb but no more than 350 kb away from each other. The orientation of the first BAC end sequence must be "+" and the orientation of the second BAC end sequence must be "-".

The scoring scheme used for this annotation assigns 1000 to an alignment when the BAC end pair aligns to only one location in the genome (after filtering). When a BAC end pair or clone aligns to multiple locations, the score is calculated as 1500/(number of alignments).

## Methods

BAC end sequences are placed on the assembled sequence using Jim Kent's blat program.

## Credits

Additional information about the clone, including how it can be obtained, may be found at the NCBI Clone Registry. To view the registry entry for a specific clone, open the details page for the clone and click on its name at the top of the page.