Analysis of the monomeric alphoid sequences in the pericentromeric region of human chromosome 7

To further define the structure of the pericentromeric region of human chro mosome 7, we have identified and characterized a YAC clone (YAC 311.H5) con taining the D7S1480 locus, which maps to the short arm near the centromere of this chromosome, by linkage in CEPH families and radiation hybrid analys is. This YAC contains two new blocks of alphoid DNA (named Z5 and Z6). Both Z5 and Z6 show monomeric structures and a lack of higher-order repeats, an d, therefore, belong to suprachromosomal family type 4 (M1). The orientatio n of the two blocks and the physical distances over the region were defined by pulsed-field gel electrophoresis (PFGE) and fluorescence in situ hybrid ization on chromatin fibers (FiberFISH). A YAC contig spanning the centrome ric region has been developed by STS content.