The Peter Pan paradigm

Genetic and environmental agents that disrupt organogenesis are numerous and well described. Less well established, however, is the role of delay in the developmental processes that yield functionally immature tissues at birth. Evidence is mounting that organs do not continue to develop postnatally in the context of these organogenesis insults, condemning the patient to utilize under-developed tissues for adult processes. These poorly differentiated organs may appear histologically normal at birth but with age may deteriorate revealing progressive or adult-onset pathology. The genetic and molecular underpinning of the proposed paradigm reveals the need for a comprehensive systems biology approach to evaluate the role of maternal-fetal environment on organogenesis.     

Natural genital herpesvirus hominis infection in chimpanzees (Pan troglodytes and Pan paniscus)

Type 2 Herpesvirus hominis was isolated from pustulovesicular lesions on the external genitalia of two chimpanzees. Histopathologic examination of biopsy specimens from both animals revealed typical herpetic changes which included necrosis, superficial ulceration acute inflammatory cell infiltration, multinucleated syncytial giant cells, and intranuclear inclusions. Large numbers of herpes-type viruses were demonstrated by electron microscopy in biopsy specimens from both animals. Serologic studies also demonstrated infection of these animals with Herpesvirus hominis.     

Pan paniscus and human evolution

Detailed comparisons of the postcranium, cranium, and dentition of Pan paniscus, Pan troglodytes, and Homo reveal that except for slight differences in fore- and hindlimb proportions and the morphology of the shoulder, the postcranium of the two species of Pan are allometrically scaled variants of the same animal and one does not resemble Homo more than the other. Nor does the postcranium of one species of Pan resemble Australopithecus more closely than the other when the effects of body size are controlled. The over all morphological pattern of the skull and teeth of the two chimpanzees is clearly different, however, but both are about equally distinct from the earliest known members of the family Hominidae.     

Dental variation in the genus Pan

Dental measurements and 23 anatomical dental features are observed on 151 Pan troglodytes and 69 Pan paniscus of both sexes, preserved in the Museum of Tervuren (Belgium). Odontometric investigations confirm the reality of the two species in the genus Pan, but do not show any difference between subspecies in Pan troglodytes. Correspondence analysis demonstrates that the qualitative anatomical features are differently distributed in the two chimpanzee species.     

Behavioral Adaptation of Pan troglodytes troglodytes

As wild primate populations decline, numbers of orphaned primates, sanctuaries, and attempts to release primates back to the natural environment increase. Release projects frequently are poorly documented despite IUCN guidelines recommending post-release monitoring and systematic data collection as central to the process. Since 1996, Habitat Ecologique et Liberté des Primates (HELP) has been releasing wild-born orphaned chimpanzees into natural habitat in the Conkouati-Douli National Park, Republic of Congo. HELP developed a post-release monitoring system as an integral component. We present activity budgets and diet of released chimpanzees, and compared them to those of wild chimpanzee, as primary indicators of successful release. Feeding, moving, and resting dominated activity budgets, reflecting the overall patterns in wild populations. Diet was diverse and dominated by fruit, and the released chimpanzees showed specialization on a smaller number of species, as in many wild communities. The high survival rates of the chimpanzees and overall success of the release program are attributed to careful planning and post-release support facilitated via the monitoring process. Systematic post-release data collection monitoring has confirmed that wild-born chimpanzees can adjust behaviorally and nutritionally to the wild. Survival statistics of the reintroduced chimpanzees—confirmed 56%, possible 88%— reflect the behavioral adaptability.2nd revision March 11, 2005An erratum to this article can be found at     

Structural basis for Pan3 binding to Pan2 and its function in mRNA recruitment and deadenylation

The conserved eukaryotic Pan2–Pan3 deadenylation complex shortens cytoplasmic mRNA 3′ polyA tails to regulate mRNA stability. Although the exonuclease activity resides in Pan2, efficient deadenylation requires Pan3. The mechanistic role of Pan3 is unclear. Here, we show that Pan3 binds RNA directly both through its pseudokinase/C‐terminal domain and via an N‐terminal zinc finger that binds polyA RNA specifically. In contrast, isolated Pan2 is unable to bind RNA. Pan3 binds to the region of Pan2 that links its N‐terminal WD40 domain to the C‐terminal part that contains the exonuclease, with a 2:1 stoichiometry. The crystal structure of the Pan2 linker region bound to a Pan3 homodimer shows how the unusual structural asymmetry of the Pan3 dimer is used to form an extensive high‐affinity interaction. This binding allows Pan3 to supply Pan2 with substrate polyA RNA, facilitating efficient mRNA deadenylation by the intact Pan2–Pan3 complex.     

The chimpanzee-specific pericentric inversions that distinguish humans and chimpanzees have identical breakpoints in Pan troglodytes and Pan paniscus

Seven of nine pericentric inversions that distinguish human (HSA) and chimpanzee karyotypes are chimpanzee-specific. In this study we investigated whether the two extant chimpanzee species, Pan troglodytes (common chimpanzee) and Pan paniscus (bonobo), share exactly the same pericentric inversions. The methods applied were FISH with breakpoint-spanning BAC/PAC clones and PCR analyses of the breakpoint junction sequences. Our findings for the homologues to HSA 4, 5, 9, 12, 16, and 17 confirm for the first time at the sequence level that these pericentric inversions have identical breakpoints in the common chimpanzee and the bonobo. Therefore, these inversions predate the separation of the two chimpanzee species 0.86-2 Mya. Further, the inversions distinguishing human and chimpanzee karyotypes may be regarded as early acquisitions, such that they are likely to have been present at the time of human/chimpanzee divergence. According to the chromosomal speciation theory the inversions themselves could have promoted human speciation.     

Vocal Production by a Language-Competent Pan paniscus

Human spoken language and nonhuman primate vocalization systems have traditionally been regarded as qualitatively different from one another with respect to their semanticity and the way in which individuals acquire and utilize these signals. However, recent studies of the vocal behaviors of both captive and free-ranging monkeys and apes suggest that this dichotomy may not be unequivocal. We examined the vocalizations produced by a linguistically-competent adult male bonobo (Pan paniscus) named Kanzi. We analyzed his vocalizations during communicative interactions with humans in order to determine whether they vary systematically according to the semantic context in which they are produced. We determined semantic contexts based upon a vocalization's co-occurrence with predefined behavioral correlates. Spectrographic and statistical analyses revealed that acoustic structure is similar among the vocalizations that occurred within a specific semantic context and structural differences are evident between the vocalizations produced in different contexts. The results provide evidence that, during communicative interactions with humans, Kanzi modulates his vocal output on both the temporal and spectral levels.     

Locomotor behavior of Pan paniscus in Zaire

The locomotor behavior of Pan paniscus was studied over a four-week period in Equateur, Republic of Zaire. Bonobos were found to be both arboreal and terrestrial in their daily activities. In the trees adult bonobos are basically quadrupedal, but they also have significant components of armswinging, diving, leaping, and bipedalism in their locomotor repertoire.     

Mandibular Shape, Ontogeny and Dental Development in Bonobos (Pan paniscus) and Chimpanzees (Pan troglodytes)

The postnatal ontogenetic patterns and processes that underlie species differences in African ape adult mandibular morphology are not well understood and there is ongoing debate about whether African ape faces and mandibles develop via divergent or parallel trajectories of shape change. Using three-dimensional (3D) morphometric data, we first tested when in postnatal development differences in mandibular shape are initially evident between sister species Pan troglodytes and P. paniscus. Next, we tested whether each species has a distinct and non-parallel trajectory of mandibular development. Mandibles sampled across a broad developmental range of wildshot bonobos (n = 44) and chimpanzees (n = 59) were radiographed and aged from their dental development. We then collected 3D landmark surface data from all the mandibles. A geometric morphometric analysis of size-corrected 3D data found that bonobos and chimpanzees had parallel and linear ontogenetic trajectories of mandibular shape change. In contrast, mandibular shape was statistically different between P. paniscus and P. troglodytes as early as infancy, suggesting that species shape differences are already established near or before birth. A linear and stable trajectory of shape change suggests that mandibular ontogeny in these apes is unimpacted by non-linear variation in tooth developmental timing.     

Handedness in captive bonobos (Pan paniscus)

Species level right-handedness is often considered to be unique to humans. Handedness is held to be interrelated to our language ability and has been used as a means of tracing the evolution of language. Here we examine handedness in 3 captive groups of bonobos (Pan paniscus) comprising 22 individuals. We found no evidence for species level handedness. Conclusions that can be drawn from these findings are: (1) species level handedness evolved after the divergence of the Pan and Homo lineages; (2) inconsistent preferences may represent precursors to human handedness, and (3) Pan may have language abilities but these cannot be measured using handedness.