A 1.2-Mb YAC contig spans the quaking region

Area of Science:

• Genomics
• Mouse Genetics
• Molecular Biology

Background:

• The quaking (qk) locus in mice is associated with neurological disorders and is a target for genetic and physical mapping.
• Understanding the genomic organization around the quaking region is crucial for identifying disease-associated genes and studying genome structure.

Purpose of the Study:

• To construct a high-resolution physical map of a 1.2-Mb yeast artificial chromosome (YAC) contig on mouse chromosome 17.
• To identify and map new DNA probes within the quaking (qk) region.
• To refine the location of deletion breakpoints associated with quaking mutations.

Main Methods:

• Construction and characterization of a yeast artificial chromosome (YAC) contig.
• Development and distribution of six new DNA probes (D17Leh502-D17Leh507).
• Physical mapping of probes on the YAC contig using restriction mapping.
• Genetic mapping of selected probes using high-resolution genetic crosses.
• Restriction mapping of wildtype and mutant DNA to pinpoint deletion breakpoints.

Main Results:

• A 1.2-Mb YAC contig was established on mouse chromosome 17, spanning the quaking region.
• Six new probes were localized on the YAC contig, with D17Leh502 and D17Leh507 at its ends.
• Most new probes, along with D17Leh508, were found within a deletion associated with the quaking(viable) (qkv) allele.
• Genetic mapping indicated that D17Leh504 and D17Leh507 are tightly linked to quaking mutations (qkv and qkl-1).
• The deletion breakpoint was localized to within 90 kb.

Conclusions:

• The developed YAC contig and mapped probes provide a valuable resource for the mouse quaking region.
• This physical map facilitates the identification of expressed sequences and the investigation of genome organization.
• The precise localization of deletion breakpoints aids in understanding the molecular basis of quaking mutations.