A detailed physical map of the 6p reading disability locus, including new markers and confirmation of recombination suppression.

Loci for several complex disorders have been genetically linked to markers located telomeric of the HLA class I region of the major histocompatibility complex on 6p21.3-22. However, this same region has been characterized by a large interval of recombination suppression with the potential to greatly complicate precise localization of these risk loci. Furthermore, a paucity of markers and physical mapping data has confounded precise localization of the boundaries of linkage and recombination suppression. In order to create a more detailed marker map of this region and define these boundaries we generated a minimal tiling pathway of BACs, PACs, and cosmids and a multiplexed panel of 29 short tandem repeat markers spanning 10 Mb. In addition to providing precise marker order and distances, the pathway and marker panel frame an inversion of recombination frequency that has distorted the resolution of linkage studies for 6p loci such as reading disability and others, and that should be accounted for in the design of future studies.