Reciprocal painting between humans, De Brazza's and patas monkeys reveals a major bifurcation in the Cercopithecini phylogenetic tree.
We report on reciprocal painting between humans and two Cercopithecini species, Erythrocebus patas (patas monkey) and Cercopithecus neglectus (De Brazza's monkey). Both human and monkeys chromosome-specific probes were made by degenerate oligonucleotide primed PCR (DOP-PCR) from flow sorted chromosomes. Metaphases of both monkey species were first hybridized with human chromosome-specific probes and then human metaphases were hybridized with chromosome paints from each monkey species. The human paint probes detected 34 homologous segments on the C. neglectus karyotype, while the C. neglectus probes, including the Y, revealed 41 homologous segments on the human karyotype. The probes specific for human chromosomes detected 29 homologous segments in the E. patas karyotype, while the patas monkey probes painted 34 segments on the human karyotype. We tested various hypotheses of Cercopithecini phylogeny and taxonomy developed by morphologists, molecular biologists and cytogeneticists. Our hybridization data confirm that fissions (both Robertsonian and non-Robertsonian) are the main mechanism driving the evolutionary trend in Cercopithecini toward higher diploid numbers and strongly suggest an early phylogenetic bifurcation in Cercopithecini. One branch leads to Cercopithecus neglectus/Cercopithecus wolfi while the other line leads to Erythrocebus patas/Chlorocebus aethiops. Allenopithecus nigroviridis may have diverged prior to this major phylogenetic node.