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We hybridized human chromosome-specific DNA probes to metaphases of the New World monkey Ateles geoffroyito map the chromosomal homology between these two species. In the haploid Ateles geoffroyi karyotype the total number of signals was 51 for the 22 human autosomal probes used. Compared with Old World monkeys, the number of translocations found in the black-handed spider monkey karyotype was quite striking. The majority of these translocations are apparently Robertsonian and no reciprocal translocations were revealed. Nine autosomal human chromosome probes (11, 13, 14, 17, 18, 19, 20, 21, 22) provided only two signals each per metaphase, but six of these were translocated to subregions of different spider monkey chromosomes. The other 13 autosomal human chromosome paints (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 16) provided fragmented signals. Three human probes (5, 8, 10) provided signals located on two pairs of spider monkey chromosomes. Four human paints (2, 3, 4, 12) provided hybridization signals on three pairs of chromosomes. Probes 6, 7, 15 provided six signals each on two pairs of chromosomes; probe 16 gave eight signals on two pairs of spider monkey chromosomes and probe 1 gave 12 signals on four pairs of chromosomes. The synteny between segments to human 18/8 appears to be an apomorphic ancestral condition for all New World monkeys. A synteny between regions homologous to human 16/10, 5/7 and 2/16 HSA is probably an apomorphic ancestral condition for all Cebidae. The syntenic association 3/15 and 4/1 is an apomorphic condition for the Atelinae.

We hybridized human chromosome-specific DNA probes to metaphases of the New World monkey Ateles geoffroyi to map the chromosomal homology between these two species. In the haploid Ateles geoffroyi karyotype the total number of signals was 51 for the 22 human autosomal probes used. Compared with Old World monkeys, the number of translocations found in the black-handed spider monkey karyotype was quite striking. The majority of these translocations are apparently Robertsonian and no reciprocal translocations were revealed. Nine autosomal human chromosome probes (11, 13, 14, 17, 18, 19, 20, 21, 22) provided only two signals each per metaphase, but six of these were translocated to subregions of different spider monkey chromosomes. The other 13 autosomal human chromosome paints (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 16) provided fragmented signals. Three human probes (5, 8, 10) provided signals located on two pairs of spider monkey chromosomes. Four human paints (2, 3, 4, 12) provided hybridization signals on three pairs of chromosomes. Probes 6, 7, 15 provided six signals each on two pairs of chromosomes; probe 16 gave eight signals on two pairs of spider monkey chromosomes and probe 1 gave 12 signals on four pairs of chromosomes. The synteny between segments to human 18/8 appears to be an apomorphic ancestral condition for all New World monkeys. A synteny between regions homologous to human 16/10, 5/7 and 2/16 HSA is probably an apomorphic ancestral condition for all Cebidae. The syntenic association 3/15 and 4/1 is an apomorphic condition for the Atelinae.

Polypterids are a group of Osteichthyan fish whose evolutionary relationships with closer basal ray-finned and lobe-finned fish have been disputed since their discovery. Very little is known about the evolutive karyology in the whole Polypteriformes group. In order to fill this gap, a cytogenetic analysis of Erpetoichthys calabaricus species was performed, using both classical and molecular techniques. Karyotype structure (2n = 36; FN = 72), chromosome location of telomeric sequences (TTAGGG) n and ribosomal 5S and 18S rRNA genes were examined in twenty specimens of E. calabaricus by using Ag-NOR, classical C-banding, sequential CMA3/4′,6-diaminidino-2-phenylindole (DAPI) staining and fluorescent in situ hybridization (FISH). CMA3 marked all centromerical and some (n°1 and n°15) telomeric regions. Staining with Ag-NOR and CMA3 showed the presence of two NORs on the p arm of the chromosome pair n°1. Hybridization with telomeric probes (TTAGGG) n showed signals at the end of all chromosomes. 5S rDNA was cloned and sequenced. After the alignment, the 5S rRNA sequences revealed an organization made up of two different classes of tandem arrays (type I and type II). FISH with 5S rDNA marked the telomeric regions of the small chromosome pair n°15, while FISH with 18S rDNA marked the telomeric region of the pair n°1. The results obtained were compared with cariological data on closer species now available in literature.

The Sarcopterygii are considered to be the living species most closely related to the ancestors of the tetrapods: they include the extinct rhipidistians, the coelacanths and the dipnoans. Furthermore, many Authors debate whether the Polypteriformes should be assigned a very peculiar place in the phylogeny of the bony fishes. To investigate the group of Polypteriformes and the Dipnoans and to provide new support for the classic morphological and molecular data and previous karyological evidence, we examined the DNA sequences of the mitochondrial genes 16S, 12S and cyt-b in two polypterids (Polypterus palmas and Erpetoichthys calabaricus) and two lungfish (Protopterus annectens and P. aethiopicus). In all the trees, Polypteriformes and Dipnoi are grouped together, while coelacanths remain as a sister group of these two. This molecular evidence supports the earliest hypotheses in which Polypteriformes were grouped in the same subclass together with the coelacanths and Dipnoi. © 2004 Taylor & Francis Group, LLC.