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At least 19 recordsLinked to original sources
PubMed1988

Genome size and constitutive heterochromatin in Hylobates muelleri and Symphalangus syndactylus and in their viable hybrid.

Genome size was measured as the amount of Feulgen-stained DNA in six species of the family Hylobatidae and in a hybrid of the gibbon (Hylobates muelleri) and siamang (Symphalangus syndactylus). The family, on the whole, exhibits a wider range of genome sizes than pongids; in particular, the siamang has about 15% more DNA than the 44-chromosome Hylobates species of the "lar" group. Quantitative analysis of C-heterochromatin in hybrid metaphases showed that the difference in genome size of the parental species correlates with the amount of C-band-positive material. Hylobatids are the only group of primates in which karyotype diversification has taken place with a massive quantitative change in constitutive heterochromatin.

Animals↗
PubMed1992

Genital swelling in females of the monogamous gibbon, Hylobates (H.) lar.

Cyclical changes in the vulvae of five adult lar gibbons (Hylobates [H.] lar) were studied and compared with those of eight lowland gorillas. The results reveal that the gibbons have relatively conspicuous and specialized sexual swellings that alter shape and appearance during the ovarian cycle. At maximum extent, the genital swellings of gorillas are relatively and absolutely smaller than those of gibbons, and lack the distinctive coloration seen in the genital swellings of the smaller apes. We conclude that the female gibbon's sexual swelling is a far more conspicuous and effective signal of estrus status than that of the gorilla, and that this is not explicable in terms of allometry. Previous investigators have pointed to one-male mating systems, monogamous pair-bonding, or an arboreal habitat as reasons that some primates should have less conspicuous signals of estrus than others. Our findings for the gibbon are the reverse of these predictions, and indicate that sexual selection other than by intermale competition for estrous females is implicated in the ultimate causation of the gibbon's swelling. The adaptive value and significance of the female gibbon's sexual signals remain unclear, however.

Animals↗
PubMed1992

The external genitalia of female gibbons, Hylobates (H.) lar.

The external genitalia of one perimenarcheal and five adult female white handed-gibbons (Hylobates (H.) lar) were examined to clarify their gross anatomy. It was found that the vulval structures were complex and exhibited inter-individual variation in arrangement. This complexity appears to result from an ontogenetic process by which the tissues of the vaginal rim (the labia minora) bud-off and extrude extensions toward the vagina immediately prior and subsequent to menarche. Two of these lobular structures surround the urethral meatus and constitute a urethral eminence. The tissues of the vulva, excluding the clitoris with associated prepuce and frenulum and vestigial labia majora, undergo cycles of tumescence and detumescence during intermenstrual intervals. The complex form of the external genitalia and the presence of a swelling cycle are unusual for a monogamous species, are contrary to current applications of sexual selection theory, and raise questions about the significance of mate choice in hominoid evolution.

Animals↗
PubMed1975

Calcification of the bladder and papillary tumours of the bladder and ureters in gibbons (Hylobates lar) infected with Schistosoma haematobium (Iran).

Many species of nonhuman primates have been employed to find parasite-definitive host combinations which would allow for investigations on different aspects of schistosomiasis haematobia. Gibbons (Hylobates lar), exposed to moderate numbers of Schistosoma haematobium cercariae, have demonstrated some of the basic features of schistosomiasis haematobia in man. Calcification in schistosomiasis haematobia is variable. Radiologically evident calcification of the bladder was noted in one gibbon. Radio-opaque areas in the bladder corresponded to dense deposits of calcified eggs observed on histological examination. Thus, it seems, bladder calcification, thought to be a later complication of schistosomiasis, can develop fairly rapidly. One of two gibbons killed 11 months after infection had small papillary transitional cell tumours in both ureters. The other had papillary transitional cell tumours covering most of the urinary bladder surface. No invasion of muscle by tumour was present and no metastases were seen.

Animals↗
PubMed1992

A phylogenetic study of the gibbons (Hylobates) using DNA obtained noninvasively from hair.

Variation in a 252-nucleotide segment of the cytochrome b gene from 26 gibbons is described. DNA was extracted from hair, amplified, and directly sequenced. These sequences represent seven of the nine nominal species and three of the four hylobatid subgenera. Variation was observed at 55 sites, 42 of which are phylogenetically informative. Levels of transitional and transversional divergence between the taxa are similar to those reported for homologous mtDNA sequences in other mammals. Parsimony, maximum likelihood, and bootstrap analyses (1) support some traditional phylogenetic hypotheses (monophyly of the concolor gibbons), (2) suggest previously unrecognized affinities between the lar species group and Hylobates klossi and between H. lar and H. agilis unko, and (3) show that this segment does not contain information sufficient for completely resolving gibbon relationships at the subgeneric level. The study demonstrates the great potential of noninvasive DNA sampling for phylogenetic analyses of mammals.

Animals↗
PubMed1975

[Karyotype analysis of 2 species of gibbons (Hylobates lar and H. concolor) with different banding species].

The mitotic chromosomes of two species of gibbons (Hylobates lar and H. concolor) are examined and compared, using various banding techniques. These two species have very different karyotypes. At the most, seven pairs of chromosomes have a similar banding pattern. The other elements generally differ by complex structrual rearrangements. Thus, it is difficult to propose a scheme for chromosomal evolution at this stage. Comparison with the karyotypes of man and anthropoid apes also shows very important differences; very few chromosomes are common or only slightly modified. Some considerations about the hypothetical origin of particular chromosomal structures are given.

Animals↗
PubMed1975

Karyotype of the gibbons hylobates lar and h. moloch inversion in chromosome 7.

A karyotype of the gibbon, Hylobates, has been prepared based on the chromosome banding patterns produced by quinacrine, trypsin-Giemsa, and centromeric heterochromatin stains. The banding patterns of H. lar and H. moloch are virtually identical. No brilliant quinacrine-fluorescent areas are present. The banding pattern of most of the gibbon chromosomes show less resemblance to those of the human, chimpanzee, gorilla, or orangutan than the chromosomes of the higher primates do to each other, suggesting a relatively large evolutionary separation of the gibbon from the higher primates. A pericentric inversion of chromosome 7 is present in one gibbon.

Animals↗
PubMed1986

Census and survey of wild black-crested gibbons (Hylobates concolor concolor) in Yunnan Province, People's Republic of China.

Black-crested gibbons (Hylobates concolor concolor) inhabit the subtropical forests of Southern China and Northern Vietnam, and have never previously been the subject of any systematic behavioral or ecological study. This report presents the findings of a three-month census and survey of black-crested gibbons in the Wuliang and Ailao Mountain Game Reserves in Yunnan province, China. The censusing methods used here were similar to those techniques used during other census studies of gibbons. The sites visited were subtropical broadleaf evergreen forests, with trees belonging to the families Fagaceae, Theaceae, Magnoliaceae, Lauraceae and Elaeocarpaceae. A total of 23-25 groups of black-crested gibbons were documented from 4 sites visited, and a group density estimate from all sites averaged 0.82 groups/km2. These gibbons were found to be polygynous with an average family group size of 7-8 animals, comprising 1 adult male, 1-4 adult females and numerous offspring of various ages. Some of the ecological and evolutionary implications of these findings are also presented.

Animals↗
PubMed1991

Karyotypic study of four gibbon forms provisionally considered as subspecies of Hylobates (Nomascus) concolor (Primates, Hylobatidae).

We report here a karyotypic study of 6 individuals of Hylobates concolor leucogenys, 2H, concolor siki, 3H, concolor gabriellae, 1 hybrid H, concolor leucogenys x H. concolor ski, 3 hybrid H. concolor gabriellae x H. concolor siki and 2 hybrid H. concolor hainanus x H. concolor leucogenys. Difficulties raised by the morphological identification of subspecies are discussed, and a new morphological characteristic for recognising female H. concolor gabriellae is described. Each of the 4 subspecies appears to be distinguishable on the basis of its karyotype: H. concolor leucogenys differs from H. concolor siki by a reciprocal translocation, from H. concolor hainanus by a pericentric inversion and from H. concolor gabriellae by the presence of both of these two rearrangements. However, these data do not allows us to identify a phylogenetic relationship between the subspecies because, with respect to the karyotypes, none occupies an ancestral position in comparison with the others.

Animals↗
PubMed1978

Experimental infection with Schistosoma intercalatum (Fisher, 1934) in the chimpanzee (pan troglodytes) and the gibbon (Hylobates lar).

Two young chimpanzees (Pan troglodytes) and two adult gibbons (Hylobates lar), each exposed to 1,000 cercariae of Schistosoma intercalatum (Cameroon), were examined at 79 and 82 wk and 61 and 69 wk, respectively, post-infection. Based upon worn returns and tissue egg deposits, these primates can be employed as hosts for experimental schistosomiasis intercalata. However, no histopathology was detected in the urogenital system.

Animals↗
PubMed1979

[Stereotype and plasticity of utterances in gibbons (Hylobates concolor leucogenys)].

The "great call" of adult male and female Hylobates concolor leucogenys was studied in different conditions of social stimulation, using quantitative (i. e. sonographic) analysis. Vocal sequences are generally made up of mixed sounds, appearing in a fixed order and constituting a species-specific character. Qualitative diversification appears in the repetition of sequences. Different social situations alter parameters of the calling pattern: especially the length and intensity of homologous modulated sounds, and the qualitative complexity of sequences. The capacity of controlling length and intensity of modulated sounds has been shown in earlier papers for H. c. gabriellae, and by several authors, in Cebus and Rhesus monkeys. The "great call" of H. c. leucogenys shows the two fundamental characteristics of instinctive (i. e. genetically determined) activity-patterns.

Animals↗
PubMed1991

Siderophilic bodies associated with hemosiderosis and atypical mycobacterial infection in an island siamang (Hylobates syndactylus).

Laminated iron concretions were noted in the liver of an aged siamang (Hylobates syndactylus) that had granulomatous enteritis and hepatitis due to Mycobacterium avium intracellulare infection. Preexisting hepatic siderosis, iron sequestration in macrophages, and compromised macrophage function due to mycobacterial infection are proposed as the basis for the abundance and size of the concretions. Similar siderophilic bodies and concomitant siderosis occurred in other siamangs. The concretions are similar to Schumann bodies and Michaelis-Gutmann bodies associated with granulomatous disease in other species.

Animals↗
PubMed1990

Molecular history of gene conversions in the primate fetal gamma-globin genes. Nucleotide sequences from the common gibbon, Hylobates lar.

Comparative and phylogenetic analyses of homologous sequences from closely related species reveal genetic events which have happened in the past and thus provide considerable insight into molecular genetic processes. One such process which has been especially important in the evolution of multigene families is gene conversion. The fetal gamma 1 and gamma 2-globin genes of catarrhine primates (humans, apes, and Old World monkeys) underwent numerous gene conversion events after they arose from a gene duplication event 25-35 million years ago. By including the gamma 1- and gamma 2-globin gene sequences from the common gibbon, Hylobates lar, the present work expands the gamma-globin data set to represent all major groups of hominoid primates. A computer-assisted algorithm is introduced which reveals converted DNA segments and provides results very similar to those obtained by site-by-site evolutionary reconstruction. Both methods provide strong evidence for at least 14 different converted stretches in catarrhine primates as well as five conversions in ancestral lineages. Features of gene conversions generalized from this molecular history are 1) conversions are restricted to regions maintaining high degrees of sequence similarity, 2) one gene may dominate in converting another gene, 3) sequences involved in conversions may accumulate changes more rapidly than expected, and 4) certain elements, such as polypurine/polypyrimidine [Y)n) and (TG)n elements, appear to be hotspots for initiating or terminating conversion events.

Amino Acid Sequence↗
PubMed1977

Successful breeding of the laboratory-housed gibbon (Hylobates lar).

A cage was developed which included a squeeze wall for easy handling of the gibbon (Hylobates lar) and which provided gibbon breeding pairs with privacy from others of the same species. Females living in this environment displayed menstrual and vaginal eversion cycles averaging 30 days (range 22-44). Twelve compatible pairs produced eight live infants from 15 conceptions in a 33-month period. Two full term stillbirths, two abortions, and three current pregnancies accounted for the other seven conceptions. Monthly uterine palpations were performed and pregnancy could be detected as early as 27 days after conception. The compatibility of the mating pairs was determined to be the major factor in the natural breeding of gibbons in captivity. This was demonstrated by obtaining only 12 compatible pairs from 22 attempted pairings.

Animals↗
PubMed1975

Localization of rDNA and Giemsa-banded chromosome complement of white-handed gibbon, Hylobates lar.

A karyotype based on banding pattern and chromosome length is presented for the white-handed gibbon, Hylobates lar. Little homology with the banding patterns of the chromosomes of the other Hominoidea can be seen, confirming the early evolutionary separation of Hylobatidae and the other apes. Hybridization in situ with ribosomal RNA shows that the secondary constriction of a submetacentric chromosome (15) is the only site of the nucleolar organizer, as in the Cercopithecoidea. The correlation of polymorphic variation in size of this secondary constriction with grain density suggests differences in the number of gene copies per chromosome.

Animals↗
PubMed1987

Accessory optic system of an anthropoid primate, the gibbon (Hylobates concolor): evidence of a direct retinal input to the medial terminal nucleus.

The accessory optic system (AOS) was studied in an anthropoid primate by using anterograde transport of tritiated amino acids and autoradiographic techniques. The course of the accessory optic tract (AOT) and the retinal projection to the terminal nuclei are described in the gibbon and compared to that of other mammals. The AOT consists of a superior fasciculus, which includes both an anterior and a posterior fiber branch. An inferior fasciculus of the AOT is absent. In contrast to previous reports in haplorhine primates, which describe the AOS as consisting of only the dorsal (DTN) and the lateral (LTN) terminal nuclei, we find that in the gibbon, three cellular groups receive a bilateral projection, predominantly from the contralateral retina. According to cytoarchitecture and topographic location, two of these nuclei correspond to the DTN and the LTN. The third cellular group, situated dorsomedial to the substantia nigra, receives a distinct retinal projection and extends rostrocaudally for 2.0 mm in the mesencephalon. This nucleus is homologous to the dorsal division of the medial terminal nucleus (MTN) in other mammals. There was no evidence for a ventral division of the MTN, which in nonprimates is typically situated at the ventromedial base of the cerebral peduncle. Examination of brain morphology in primates suggests that the ventral division of the MTN has been displaced from its phylogenetically stable location in the medial part of the ventral midbrain to a more dorsal position. This shift appears to be a consequence of the overall morphological influences resulting from the relative enlargement of the pons in this region. The demonstration of a direct retinal projection to the MTN in the gibbon, as well as recent reports in other primates, indicates that a complete AOS consisting of three terminal nuclei is a feature common to all mammals.

Animals↗