An alphoid DNA sequence conserved in all human and great ape chromosomes: evidence for ancient centromeric sequences at human chromosomal regions 2q21 and 9q13

Using vector-CENP-B box polymerase chain reaction (PCR) we isolated and cloned from a human chromosome 21-specific plasmid library, a 1 kb DNA sequence, named pαH21. In in situ hybridization experiments, pαH21 hybridized, under high stringency conditions, to the centromeric region of all the human, chimpanzee, gorilla and orangutan chromosomes. On human chromosomes pαH21 also identified non-centromeric sequences at 2q21 (locus D2F33S1) and 9q13 (locus D9F33S2). The possible derivation of these sequences from ancestral centromeres is discussed. Sequence analysis confirmed the alphoid nature of the whole pαH21 insert.