A CONTIG OF NON-CHIMERIC YACS CONTAINING THE SPINAL MUSCULAR-ATROPHY GENE IN 5Q13

We have constructed a contig of non-chimaeric yeast artificial chromos omes (YACs) across the candidate region for childhood autosomal recess ive spinal muscular atrophy (SMA) in 5q13. A novel microsatellite redu ces the candidate region to approximately 400kb of DNA distal to D5S43 5. The candidate region contains blocks of chromosome 5 specific repea ts which have copies on 5p as well as elsewhere on 5q. Restriction map ping of the YACs reveals at least one CpG island in the SMA gene regio n. The YAC maps indicate that the contig contains minimal rearrangemen ts or deletions. The data show the value of screening several YAC libr aries simultaneously in order to construct a set of overlapping sequen ces suitable for candidate gene searches and direct genomic sequencing .