Chromosome painting reveals that galagos have highly derived karyotypes†

Abstract

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.

The phylogenetic position of Daubentonia madagascariensis (Gmelin, 1788; primates, Strepsirhini) as revealed by chromosomal analysis

“…These include HSA2/4, 4/6 and 8/15 associations in all lemuriforms (Carbone et al 2002;Warter et al 2005), and HSA1q/19p, 2/12, 6/14, 12/7/16, 9/15 and 10/19q association in lorisiforms (Stanyon et al 2002;Nie et al 2005), with the exception of Daubentonia madagascariensis which certainly occupies an uncharacteristic position (present study). This has already been observed by early chromosomal banding studies (R-banding) where Daubentonia unequivocally held a distinct position from other lemurs (Rumpler et al 1988;Poormann-Allen and Izard 1990;Dutrillaux and Rumpler 1995).…”

Reciprocal chromosome painting among human, aardvark, and elephant (superorder Afrotheria) reveals the likely eutherian ancestral karyotype

“…The Hsa 1͞19p association detected in both the elephants and aardvark has also been found in the galago (Otolemur crassicaudatus, ref. 31), and it too is likely to be ancestral for all eutherians. Should this hold, elephant chromosomes 2 and 19 can be derived from the aardvark chromosome 3q via one fission.…”

Towards the delineation of the ancestral eutherian genome organization: comparative genome maps of human and the African elephant (Loxodonta africana) generated by chromosome painting

“…Yang et al hypothesize that an association of HSA 1 and 19 is part of the ancestral placental karyotype, because it is also found outside the Afrotheria in a primate, the galago (Stanyon et al 2002). However, this is the only occurrence of this association in a species which is not a well suited model for ancestral karyotype forms, because of its highly rearranged karyotype (Stanyon et al 2002). A comparison of G-banding patterns of the galago and the aardvark and elephant makes it seem very likely that the HSA 19 homologous segment is fused to different parts of HSA 1 in the galago and in the Afrotheria.…”