The existence of an apomorphic reciprocal chromosomal translocation in the gorilla lineage has been asserted or denied by various cytogeneticists. We employed a new molecular cytogenetic strategy (chromosomal in situ suppression hybridization) combined with high-resolution banding, replication sequence analysis, and fluorochrome staining to demonstrate that a reciprocal translocation between ancestral chromosomes homologous to human chromosome 5 and 17 has indeed occurred. o 1992 Wiley-Liss, Inc.

The high-quality karyotype of a specimen of Nycticebus coucang is described and illustrated. The X chromosome is found to be indistinguishable from that of the greater galagos, and may represent a synapomorphic trait. The y chromosome is a medium to small submetacentric (3.2% TCL) and constitutes one of the larger Y chromosomes known in primates. N. coucang is found to have multiple NOR-bearing chromosomes in contrast to the single pair found in galagine and catarrhine monkeys. Since a single NOR-bearing pair is often considered ancestral for primates, this new finding may have important implications for the evolution of these cistrons. One of the chromosomal polymorphisms in this specimen is a pericentric inversion, involving a NOR-bearing autosomal pair (no. 6), that alters the position of the active site. Further, homologues 2p differ by a paracentric inversion. These results confirm that lorisiforms are characterized by considerable chromosomal polymorphism.

Karyotypes were analyzed of 21 greater galagos, using classical, G-banding, C-banding and silver nitrate staining techniques. A composite G-banded karyotype and high resolution idiogram are presented for each species. Areas of possible rearrangement are identified. The results support the interpretations derived from earlier, unbanded studies, rather than a more recent proposal from G-banded data. Failure of repeated attempts to obtain C-bands, despite success in human controls, indicates that the heterochromatic bands generally revealed by these staining methods are either absent or extremely small in greater galagos. Silver staining revealed a single pair of NOR-bearing autosomes in both species, as shown by previous authors.

Human chromosome 7 (HSA7) derives, by a pericentric inversion and a paracentric inversion, from an ancestral chromosome homologous to chromosome 10 of Pongo pygmaeus (the Asiatic Orang-Utan). Nevertheless the genesis of this autosome during primates evolution is not clear. Even if chromosome painting shows that HAS 7 synteny is highly conserved, GTG-banding comparison in Hominoidea and Cercopithecoidea indicates the probable occurrence of complex rearrangements during the evolution. In this study we used a single locus FISH approach, a powerful tool to detect fine rearrangements, in order to investigate the evolution of HAS 7. We report the chromosome mapping of Williams-Beuren syndrome locus (WS-HSA 7q11.23) on Macaca fascicularis (MFA), Cercopithecus (Chlorocebus) aethiops (CAE) and Trachypithecus cristatus (TCR) (Cercopithecoidea, Primates). The probe hybridises on all species tested and demonstrates the occurrence of rearrangements like fusion, fission and pericentric plus paracentric inversions respectively in MFA, CAE and TCR. Together with the first chromosome mapping of WS locus in Cercopithecoidea, this study confirms that single locus mapping is a very efficacious tool for the analysis of chromosomal rearrangements as it gave the opportunity to have a fine molecular confirmation to proposed banding patterns homologies.

I geni TBX appartengono ad una famiglia di geni omeotici (t-box) per la quale è stato dimostrato come le mutazioni dei geni comportino pesanti conseguenze sullo sviluppo. In particolare ci sono importanti evidenze a sostegno del coinvolgimento del gene TBX1 nella sindrome DiGeorge/Velocardiofacciale (DGS/VCFS) ed è stato dimostrato che i geni TBX3 e TBX5 sono implicati rispettivamente, nella UMS (Ulnar Mammary Syndhrome) e nella sindrome di Holt-Oram (HOS). Nel libro sono raccolte le informazioni sui geni TBX dell'uomo disponibili in letteratura fino ad ottobre 2001. L'esame dei dati ha consentito di arrivare ad interessanti considerazioni ed offre spunti per orientare le ricerche future.