We have identified two allelic genomic cosmids from human chromosome 2, c8.1 and 
c29B, each containing two inverted arrays of the vertebrate telomeric repeat in 
a head-to-head arrangement, 5'(TTAGGG)n-(CCCTAA)m3'. Sequences flanking this 
telomeric repeat are characteristic of present-day human pretelomeres. BAL-31 
nuclease experiments with yeast artificial chromosome clones of human telomeres 
and fluorescence in situ hybridization reveal that sequences flanking these 
inverted repeats hybridize both to band 2q13 and to different, but overlapping, 
subsets of human chromosome ends. We conclude that the locus cloned in cosmids 
c8.1 and c29B is the relic of an ancient telomere-telomere fusion and marks the 
point at which two ancestral ape chromosomes fused to give rise to human 
chromosome 2.