Interspecific Chromosome Painting Provides Clues to the Ancestral Karyotype of the New World Monkey Genus Aotus

The Neotropical monkey genus Aotus (owl or night monkeys) are among the most karyological diverse primates of the world. Their diploid numbers range from 2n = 46 to 58, but even owl monkeys with the same diploid number may have radically different karyotypes. This karyotypic variability has provided precious informa- tion for taxonomists and has a potential for aiding phylo- genetic analysis of these primates. However, up to now only three out of 11 species have been analyzed with molecular cytogenetic methods. Here, we report on a fourth species, A. infulatus. Females have a diploid num- ber of 2n = 50 while males, due to a Y/autosome translo- cation, have 49 chromosomes. We provide a complete map of chromosome homology between humans and A. infulatus. Comparisons with previous reports allowed us to propose a putative ancestral karyotype of the genus (2n = 52) and to deduce the rearrangements that were involved in the origin of each species chromosome com- plement. Integration of chromosome painting and banding analysis suggests at least three chromosomes have evolu- tionary new centromeres that appeared during the diver- gence of these four owl monkey species.