Conserved chromosome segments in <i>Hylobates hoolock</i> revealed by human and <i>H. leucogenys</i> paint probes

Abstract

A complete comparative chromosome map of the white-browed gibbon (<i>Hylobates hoolock,</i> 2n = 38), white-cheeked gibbon (<i>Hylobates leucogenys,</i> 2n = 52), and human has been established by hybridising <i>H. leucogenys</i> chromosome-specific paints and human 24-colour paints onto <i>H. hoolock</i> metaphase chromosomes. In the 18 <i>H. hoolock</i> autosomes, we identified 62 conserved segments that showed DNA homology to regions of the 25 <i>H. leucogenys</i> autosomes. Numerous interchromosomal rearrangements differentiate the karyotypes of <i>H. leucogenys</i> and <i>H. hoolock.</i> Only <i>H. hoolock</i> chromosome 10 showed homology to one entire autosome of <i>H. leucogenys.</i> The hybridisation of human 24-colour paints not only confirmed most of the chromosome correspondences between human and <i>H. hoolock</i> established previously but also helped to correct five erroneous assignments and revealed three new segments. Our results demonstrate that the karyotypes of the extant gibbons have arisen mainly through extensive translocation events and that the karyotype of <i>H. hoolock</i> more closely resembles the ancestral karyotype of <i>Hylobates,</i> rather than the karyotype of <i>H. leucogenys.</i>