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The karyotypes of four species of Cercopithecidae: Cercopithecus aethiops tantalus, C. sabaeus, Erythrocebus patas, and Miopithecus talapoin are analysed with nearly all the banding techniques. They are compared with each other, and with the karyotypes of the Baboon P. papio and with that of man. It can be concluded that the quasi-totality or the totality of the euchromatin is common to all, but has undergone structural rearrangements, generally detectable. The heterochromatin, defined by C-band staining, and late-replicating DNA, in contrast, appears very variable: In particular, E. patas has acquired very large heterochromatic segments. The significance of these modifications is discussed.

The karyotype, comprised of 62 chromosomes, of Galago crassicaudatus is described. It is compared to the karyotype of Galago senegalensis and to that of the presumed common ancestor to Lorisiforms, previously reconstructed. Most of the reconstructed chromosomes were found, unmodified, in G. crassicaudatus, strengthening the validity of the reconstruction.

The karyotypes of several Hylobatidae Hylobates (Hylobates) lar pileatus, H. (Nomascus) concolor leucogenys, H. (N.) concolor ssp, Hybrid H. (N.) concolor leucogenys x H. (N.) concolor gabriellae, H (Symphalangus) syndactylus are compared both each others and also to those of other Primates. Many rearrangements of their chromosomes have occurred during their evolution, and some polymorphism still exists in the living species. This high rate of chromosome rearrangements is in contrast with their phenotypic stability. It is very likely that reciprocal translocations have occurred, these rearrangements being very rare in the evolution of other Primates.

The effect of low-dose (0-0.5 Gy) gamma-radiations was studied on R-banded chromosomes from lymphocytes of healthy donors of various ages. In cells from newborns, an increase of chromosome damage roughly proportional to the dose was found. In lymphocytes from young adults chromosomal aberrations were not detected at doses of 0.05 and 0.1 Gy, and in lymphocytes from old adults chromosomal aberrations were not detected at doses of 0.05 and 0.1 Gy, and in lymphocytes from old adults not even at 0.2 Gy. The difficulty in detecting aberrations in lymphocytes from adults is largely due to a considerable background of chromosomal anomalies which should be borne in mind in dosimetry studies. The rate of induction largely depends on the types of rearrangements. One-break terminal deletions are efficiently induced at 0.1 and 0.2 Gy and are the best indicators of exposure at these doses. At 0.5 Gy, the frequencies of 2-break lesions, i.e., dicentrics and reciprocal translocations, increase, whereas that of deletions decreases.

Chromosome analysis by handling techniques of 19 species and sub-species of Cercopithecinae shows an important accumulation of chromosome rearrangements (51). With a clear predominance of fissions (26) and of inversions (17). It is impossible to reconstruct a simple genealogy of these species because chromosomal evolution did not follow the principle of a strict dichotomy. The progressive increase of the number of chromosomes, by fission, corresponds to the inverse of the Robertsonian evolution and suggests the existence of numerous interstitial centromeres and telomeres.

The karyotypes of two species of African Colobidae, Colobus vellerosus and C. palliatus, as well that of their hybrid, are described and compared. The two species differ by four pericentric inversions, indicating species divergence a relatively long time ago. Chromosome banding analogies with Papioninae, Cercopithecinae, and man are described. A common origin for Papioninae, Cercopithecinae, and Colobidae is indisputable; but, there are no arguments for considering that a close relationship exists between Colobidae and Hylobatidae as suggested by some authors.

Replication times for all important chromosome bands, of both types R and Q (277 structures) are analysed. The R-bands form a group of structures whose DNA replicates during the early S-phase, while the DNA situated in the Q-bands replicates during the late S-phase. There may not exist overlapping between replication times of these two types of structures. The widest R-bands are those which are the earliest to replicate; in general, the most intense Q-bands are those which are the latest to replicate. Especially among these last ones, a certain asynchronism exists between the replication times. Finally the heterochromatin of chromosomes 1, 16 and Y and of the short arms of the acrocentrics could contain two types of DNA which replicate at different times.

The karyotypes of Cebus capucinus and C. nigrivittatus (Primates, Platyrrhini) are compared after applying several banding techniques. The chromosomes have abundant intercallary heterochromatin which can be stained by R-, T- and C-band techniques and which are late replicating. The X chromosome resembles that of man and of numerous primates. However, the late replicating pattern of the X in female lymphocytes resembles that of the late replicating X of human fibroblasts rather than of human lymphocytes. Banding patterns of certain chromosomes appear analogous in Cebus and Cattarhini, including Man.

New techniques for obtaining high resolution banding are used in comparative cytogenetics. They make possible a direct comparison of the chromosomes of two distantly related primates, man and Lagothrix lagotricha (Platyrrhine). For many chromosomes, the homoeologies of banding are surprisingly clear. These new results strongly strengthen the interpretations proposed with the use of more conventional banding techniques.

A chromosomal banding study was carried out on Propithecus verreauxi verreauxi, P. verreauxi deckeni, and Avahi laniger laniger. Comparison of their karyotypes with those of Microcebus murinus and Lemur fulvus led to reconstruction of the ancestral Lemuriform karyotype and a determination that the branch leading to the Indridae was isolated very early, before the separation of the Lemuridae from the Cheirogaleidae. The karyotype of Avahi remained highly ancestral, whereas that of P. verreauxi was considerably modified, chiefly by Robersonian translocations.

Replication patterns after 5-bromodeoxyuridine incorporation are analyzed in chromosomes of four species of the genus Cebus (C. capucinus, C. albifrons, C. appella, and C. nigrivittatus). They are compared with those of man, taking as reference the banding analyses previously described. It was found that the high degree of conservation of chromosome structures between Cebus and man was accompanied by conservation of the DNA-replication sequence of the bands. It is assumed that this conservation during the course of evolution may apply to other mammals. Thus, replication patterns may be useful for ensuring interspecific comparisons. The only detected difference concerns late-replicating X chromosomes from normal female cells: The predominant lymphocyte pattern described in man is rare in Cebus, in which the usual lymphocyte pattern corresponds to that of human fibroblasts or to the minor human lymphocyte pattern.

Neuroblastic tumours are composed of variable proportions of neuroblasts and Schwann cells. Whether both components share a common neoplastic origin is highly debated and discrepant results have been reported about the presence of tumour-related genetic alterations in Schwann cells. We have used X-methylation analysis and array-CGH to investigate contiguous Schwannian and neuroblastic areas in tumours with a nodular pattern. A skewed X inactivation was observed in four out of five stromal components. Interestingly, in these four cases, the X-inactivation profiles of the neuroblastic components were identical to the matched stromal areas. However, whereas all neuroblastic areas displayed chromosomal imbalances, no alteration was found in any Schwann cell components. Similarly, no alteration was observed in a series of 19 tumours with a single stroma-rich component, which occasionally exhibited a skewed X-inactivation pattern (3/17 informative tumours). Altogether, this indicates that most stroma-rich tumours display a polyclonal proliferation and that Schwann cells do not derive from neuroblasts. However, in tumours with both stroma-rich and -poor components, our results suggest that cells from both areas share a common progenitor.Oncogene (2008) 27, 3066–3071; doi:10.1038/sj.onc.1210965; published online 10 December 2007 [ABSTRACT FROM AUTHOR]