Panel of aneuploid cell lines for physical mapping of the proximal long arm of human chromosome 21.

Some forms of familial Alzheimer disease (FAD) have shown linkage to DNA probes for the loci D21S1 and D21S16 on chromosome 21. To investigate the physical location of these DNA probes, we have constructed a physical map of this region of chromosome 21 by using quantitative Southern blot analysis of DNA sequences unique to chromosome 21 and a series of cell lines aneuploid for parts of chromosome 21. We now show that both D21S16 and D21S1/S11 are located in the same region of chromosome 21, in q11.2-q21.05. This new panel of aneuploid cell lines will allow the rapid mapping of new DNA probes in the vicinity of the FAD gene.