UNIQUE GENOMIC SEQUENCES IN HUMAN-CHROMOSOME 16P ARE CONSERVED IN THEGREAT APES

In humans, acute myelomonocytic leukemia (AMML) with abnormal bone mar row eosinophilia is diagnosed by the presence of a pericentric inversi on in chromosome 16, involving breakpoints p13;q23 [i.e., inv(16)(p13; q23)]. A pericentric inversion involves breaks that have occurred on t he p and q arms and the segment in between is rotated 180 degrees and reattaches. The recent development of a ''human micro-coatasome'' pain ting probe for 16p contains unique DNA sequences that fluorescently la bel only the short arm of chromosome 16, which facilitates the identif ication of such inversions and represents an ideal tool for analyzing the ''divergence/convergence'' of the equivalent human chromosome 16 ( PTR 18, GGO 17 and PPY 19) in the great apes, chimpanzee, gorilla and orangutan. When the probe is used on the type of pericentric inversion characteristic of AMML, signals are observed on the proximal portions (the regions closest to the centromere) of the long and short arms of chromosome 16. The probe hybridized to only the short arm of all thre e ape chromosomes and signals were not observed on the long arms, sugg esting that a pericentric inversion similar to that seen in AMML has n ot occurred in any of these great apes.