SEQUENCE ORGANIZATION OF THE HUMAN-CHROMOSOME 2Q TELOMERE

The terminal 240 kb of a human 2q telomere region was cloned in two ov erlapping yeast artificial-chromosomes (YACs). This DNA contains a reg ion of low-copy subtelomeric repeats (within 50 kb of the 2q telomere) , a segment of DNA duplicated on distal 8p23 (100 kb from the 2q telom ere), and a region of single-copy DNA (230 kb from the 2q telomere). T wo CpG islands are present in the DNA segment duplicated on distal 8p2 3. RecA-assisted restriction endonuclease cleavage of genomic DNA samp les revealed a potential 55 kb chromosome length polymorphism at the 2 q telomere. This work provides telomeric closure of maps for human chr omosome 2q, demonstrates a novel, subtelomere-specific DNA duplication , and will permit detailed molecular and cytological studies of this h uman telomere region.