Fluorescene in situ hybridization establishes homology between human and silvered leaf monkey chromosomes, reveals reciprocal translocations between chromosomes homologous to human Y/5, 1/9, and 6/16, and delineates an X1X2Y1Y2/X1X1X2X2 sex-chromosome system.

We employed in situ hybridization of chromosome-specific DNA probes ("chromosome painting") of all human chromosomes to establish homologies between the human and the silvered lead monkey karyotypes (Presbytis cristata 2n = 44). The 24 human paints gave 30 signals on the haploid female chromosome set and 34 signals on the haploid male chromosome set. This difference is due to a reciprocal translocation between the Y and an autosome homologous to human chromosome 5. This Y/autosome reciprocal translocation which is unique among catarrhine primates has produced a X1X2Y1Y2/X1X1X2X2 sex-chromosome system. Although most human syntenic groups have been maintained in the silvered leaf monkey chromosomes homologous to human chromosomes 14 and 15, 21 and 22 have experienced Robertsonian fusions. Further, the multiple FISH signals provided by libraries to human chromosomes 1/9, 6/16 indicate that these chromosomes have been split be reciprocal translocations. G-binding analysis shows three different forms of chromosome 1 (X2) which differ by a complex series of inversions in the 10 individuals karyotype. Comparisons with the hybridization patterns in hylobatids (gibbons and siamang) demonstrate that resemblances in chromosomal morphology and banding previously taken to indicate a special phylogenetic relationship between gibbons and colobines are due to convergence.