A radiation hybrid breakpoint map of the acute myeloid leukemia (AML) and limb-girdle muscular dystrophy 1A (LGMD1A) regions of chromosome 5q31 localizing 122 expressed sequences

We have constructed a high-resolution map of a 6-Mb interval of human chromosome 5, band q31, incorporating 175 sequence tagged sites, of which 33 are genetic polymorphisms and 122 are nonredundant expressed sequences. The map was assembled initially as a YAC contig, incorporating data from radiation hybrid maps. To improve resolution and to identify errors in the databases, a radiation hybrid breakpoint map was developed for the interval, which included hybrids from both Stanford G3 and GeneBridge 4 panels. This novel approach facilitated the integration of one RH panel with another and enabled the identification and localization of new, previously unmapped ESTs from the radiation hybrid databases. ESTs were assembled into overlapping transcription units and ordered with respect to polymorphic markers in the region, resulting in a comprehensive map that incorporates markers from multiple different types of maps. This map of 5q31 will facilitate gene discovery efforts for several disorders, including limb-girdle muscular dystrophy type 1A and the genes deleted in acute myeloid leukemias and myelodysplasia. The study demonstrates the utility of a radiation hybrid breakpoint panel for correction of map errors and for the efficient identification of new transcript units in a large genom interval.