Chromosome painting reveals that galagos have highly derived karyotypes †

The differences in chromosome number between Otolemur crassicaudatus (2n = 62) and Galago moholi (2n = 38) are dramatic. However, the total number of signals given by hybridizing human chromosome paints to galago metaphases is similar: 42 in O. crassicaudatus and 38 G. moholi . Many human chromosome homologs are found fragmented in each species, and numerous translocations have resulted in chromosomal syntenies or hybridization associations which differ from those found in humans. Only 7 human autosomes showed conserved synteny in O. crassicaudatus , and 9 in G. moholi . Both galago species have numerous associations or syntenies not found in humans: O. crassicaudatus has 11, and G. moholi has 21. The phylogenetic line leading to the last common ancestor of the two galago species accumulated 6 synapomorphic fissions and 5 synapomorphic fusions. Since the divergence of the two galago species, 10 Robertsonian translocations have further transformed the G. moholi karyotype, and 2 fissions have been incorporated into the O. crassicaudatus karyotype. Comparison with other primates, tree shrews, and other mammals shows that both galagos have karyotypes which are a mixture of derived and conserved chromosomes, and neither has a karyotype close to that of the proposed ancestor of all primates. Am J Phys Anthropol 117:319–326, 2002. Published 2002 Wiley‐Liss, Inc.