Use of leaves for drinking water

The use of leaves for drinking water is a widespread tool-use behavior among chimpanzees. Although this tool-use behavior is widely described as the use of leaf sponges, it can actually be found in three different forms: leaf sponges, leaf-folding, and leaf spoons. Among the chimpanzee community of Bossou, we can observe all three forms, albeit in different frequencies. Here I describe the longitudinal record of manufacture and use of leaf tools for drinking water, highlighting the learning process underlying the acquisition of the skill. The degree of laterality evident in both immature and mature performers is also presented here. The use of leaves for drinking water emerges at the age of 1.5 years old, but the manufacture of leaf tools only starts at 3.5 years of age. Infants and juveniles were observed to use drinking tools that had been discarded by other individuals after use. Concerning handedness in general, the chimpanzees are ambidextrous, with some individuals biased to one side.

Signatures of selection in the human olfactory receptor OR5I1 gene

The human olfactory receptor repertoire is reduced in comparison to other mammalsand to other non-human primates. Nonetheless, this olfactory decline opens an opportunity forevolutionary innovation and improvement. In the present study, we focus on an olfactoryreceptor gene, OR5I1, which had previously been shown to present an excess of amino acidreplacement substitutions between humans and chimpanzees. We analyze the geneticvariation in OR5I1 in a large worldwide human panel and find an excess of derived allelessegregating at relatively high frequencies in all populations. Additional evidence for selectionincludes departures from neutrality in allele frequency spectra tests but no unusually extendedhaplotype structure. Moreover, molecular structural inference suggests that one of thenonsynonymous polymorphisms defining the presumably adaptive protein form of OR5I1may alter the functional binding properties of the olfactory receptor. These results arecompatible with positive selection having modeled the pattern of variation found in the OR5I1gene and with a relatively ancient, mild selective sweep predating the “Out of Africa”expansion of modern humans.

Genetic characterization of the ABO blood group in Neandertals

Background: The high polymorphism rate in the human ABO blood group gene seems to be related to susceptibility to different pathogens. It has been estimated that all genetic variation underlying the human ABO alleles appeared along the human lineage, after the divergence from the chimpanzee lineage. A paleogenetic analysis of the ABO blood group gene in Neandertals allows us to directly test for the presence of the ABO alleles in these extinct humans. Results: We have analysed two male Neandertals that were retrieved under controlled conditions at the El Sidron site in Asturias (Spain) and that appeared to be almost free of modern human DNA contamination. We find a human specific diagnostic deletion for blood group O (O01 haplotype) in both Neandertal individuals. Conclusion: These results suggest that the genetic change responsible for the O blood group in humans predates the human and Neandertal divergence. A potential selective event associated with the emergence of the O allele may have therefore occurred after humans separated from their common ancestor with chimpanzees and before the human-Neandertal population divergence.

Long-term persistence of HIV-1 vaccine-induced CD4+CD45RA-CD62L-CCR7- memory T-helper cells.

OBJECTIVE: To determine in chimpanzees if candidate HIV-1 subunit protein vaccines were capable of eliciting long-lasting T-cell memory responses in the absence of viral infection, and to determine the specific characteristics of these responses. DESIGN: A longitudinal study of cell-mediated immune responses induced in three chimpanzees following immunization with subunit envelope glycoproteins of either HIV-1 or herpes simplex virus (HSV)-2. Following these pre-clinical observations, four human volunteers who had been immunized 7 years previously with the same HIV-1 vaccine candidate donated blood for assessment of immune responses. METHODS: Responses were monitored by protein and peptide based ELISpot assays, lymphocyte proliferation, and intracellular cytokine staining. Humoral responses were assessed by enzyme-linked immunosorbent assay and virus neutralization assays. RESULTS: Although antigen (Ag)-specific CD4 T-cell responses persisted for at least 5 years in chimpanzees, CD8 T-cell responses were discordant and declined within 2 years. Detailed cellular analyses revealed that strong Th1 in addition to Th2 type responses were induced by AS2/gp120 and persisted, whereas CD8 T-cell memory declined in peripheral blood. The specificity of both Th and cytotoxic T-lymphocyte responses revealed that the majority of responses were directed to conserved epitopes. The remarkable persistence of Ag-specific CD4 T-cell memory was characterized as a population of the CD45RA-CD62L-CCR7- "effector phenotype" producing the cytokines IFNgamma, IL-2 and IL-4 upon epitope-specific recognition. Importantly, results in chimpanzees were confirmed in peripheral blood of one of four human volunteers studied more than 7 years after immunization. CONCLUSION: These studies demonstrate that epitope-specific Th1 and Th2 cytokine-dependent Th responses can be induced and maintained for longer than 5 years by immunization with subunit proteins of HIV-1.

Aportación a un estudio de la conducta en la naturaleza de los chimpancés y su importancia en la evolución de los primates superiores

Los recientes estudios de campo han patentizado la elevada capacidad de los chimpancés para modificar su conducta. En este contexto aparte de las adaptaciones filogenéticas, bien estudiadas, es preciso significar la importancia de las ontogenéticas integradas por: las resultantes de factores climáticos, geológicos, botánicos, antropológicos, etc., y las provocadas por causas sociales motivadas, principalmente, por individuos integrantes del grupo. Cuando tales cambios sociales y culturales pueden perpetuarse durante varias generaciones en concreto hablar de protoculturas o culturas elementales; las mismas pueden dividirse en: sociales y materiales, siendo las últimas el objcto de este estudio. Parece existir una cultura chimpancé lítica, correspondiente a la subespecie Pan troglodytes verus ubicada en la Costa de Marfil y Liberia; otra de los bastones, patrimonio de algunas poblaciones de la subespecie Pan troglodytes troglodytes que viven en S. Camarones, Rio Muni y Gabón y, finalmente, otra de las hojas y sus peciolos que correspondiente a la subespecie Pan troglodyte schveinfurthi quedaria localizada en Tanzania occidental y Uganda. La protocultura de los bastones fue descubierta y estudiada por el autor de este trabajo durante un programa de estudios primatologicos patrocinado y subvencionado por la Tulane University, el National Institute of Health y la National Geographic Society de los Estados Unidos de América. Esta investigación se llevó a cabo en Rio Muni de 1966 a 1968. Las referidas industrias elementales coadyuvan al conocimiento de la extraitordinaria capacidad conductual adaptativa de estos póngidos y su dinámica en una línea que muchos especialistas no dudan en calificar de humanoide

Conducta instrumental del chimpace (Pan troglodytes) en su habitat natural

La constatación del uso sistemático de instrumentos por los chimpancés en su habitat natural ha planteado el problema de la aplicación del término cultura a un primate no humano. Una de las características de la cultura es la aparición de variantes conductuales en grupos separados. El propósito de este trabajo es revisar, con los datos disponibles en la actualidad, la hipótesis formulada por Sabater Pi (1974b) de que existen tres zonas culturales en los chimpancés e intentar identificar el origen ecológico y/o social de estas diferencias.

The effect of innovation and sex-specific migration on neutral cultural differentiation

Studies of behaviour are increasingly focusing on acquisition of traits through cultural inheritance. Comparison of patterns of spatial population structure (FST) between neutral genetic loci and behavioural or cultural traits can been used to test hypotheses about demography, life history, and the mechanisms of inheritance/transmission of these traits in humans, chimpanzees and other animals. Here, we develop analytical expectations to show how FST in cultural traits can differ strongly from that measured at neutral genetic markers if migration is largely restricted to one sex but social learning is predominantly modelled on the other (e.g. males migrate, females serve as models for cultural traits), if one individual is the learning model for many, or if rates of innovation (individual learning) are high or rates of social learning are low. We discuss how comparisons of FST between genetic loci and behavioural traits can be applied to evaluate the importance of innovation in shaping patterns of cultural differentiation, as even low rates of innovation can considerably reduce FST, relative to observed structure at neutral genetic loci. Our results also suggest that differentiation in neutral cultural traits should occur over much smaller scales in species with male migration and female enculturation (or the reverse).

Low Y chromosome variation in Saudi-Arabian hamadryas baboons (Papio hamadryas hamadryas).

It is important to characterise the amount of variation on the mammalian Y chromosome in order to assess its potential for use in evolutionary studies. We report very low levels of polymorphism on the Y chromosome of Saudi-Arabian hamadryas baboons, Papio hamadryas hamadryas. We found no segregating sites on the Y, despite sequence analysis of 3 kb noncontiguous intron sequence in 16 males with divergent autosomal microsatellite genotypes, and a further analysis of 1.1 kb intron sequence in 97 males from four populations by SSCP. In addition, we tested seven human-derived Y-linked microsatellites in baboons. Only four of these loci were male-specific and only one was polymorphic in our 97 male sample set. Polymorphism on the Y chromosome of Arabian hamadryas appears to be low compared to other primate species for which data are available (eg humans, chimpanzees and bonobos). Low effective population size (Ne) of paternal genes due to polygyny and female-biased adult sex ratio is a potential reason for low Y chromosome variation in this species. However, low Ne for the Y should be counterbalanced to some extent by the species' atypical pattern of male philopatry and female-biased dispersal. Allelic richness averaged over seven loci was not significantly different between an African and an Arabian population, suggesting that loss of variation during the colonisation of Arabia does not explain low Y variation. Finally, in the absence of nucleotide polymorphism, it is unclear to what extent selection could be responsible for low Y variation in this species.

Protection against Plasmodium falciparum challenge induced in Aotus monkeys by liver-stage antigen-3-derived long synthetic peptides.

The vaccine potential of Plasmodium falciparum liver stage antigen-3 (LSA3) was investigated in Aotus monkeys using two long synthetic peptides corresponding respectively to an N-terminal non-repeat peptide (NRP) and repeat 2 (R2) region of the LSA3, adjuvanted by ASO2. Both 100-222 (NRP) and 501-596 repeat peptides induced effector B- and T-cell responses in terms of antigen-driven antibodies and/or specific IFN-gamma secretion. Animals challenged with P. falciparum sporozoites were protected following immunization with either the NRP region alone or the NRP combined with the R2 repeat region, as compared with controls receiving the adjuvant alone. These results indicate that the NRP may be sufficient to induce full, sterile protection and confirm the vaccine potential of LSA3 previously demonstrated in chimpanzees and in Aotus.

Ximpanzés maltractadors de femelles

De vegades els ximpanzés es comporten de manera agressiva cap als seus congèneres. Fa temps que s'estudien les batusses que de tant en tant mantenen els mascles de diferents grups, i se sap que en alguns casos diversos mascles s'han associat per assassinar un company que s'hagi mostrat especialment dominant. Joseph T. Feldblum i els seus col·laboradors, en diverses universitats i centres de recerca dels EUA, han analitzat un comportament agressiu molt específic que manifesten alguns ximpanzés mascle cap a les femelles del seu grup. Els resultats, publicats a Current Biology, indiquen que, paradoxalment, aquests mascles tenen més descendents que els no agressius, perquè les femelles que s'han aparellat amb ells rebutgen posteriors còpules amb altres mascles.

Comparative anatomy of the thigh nerves of Cebus libidinosus (Rylands et al., 2000)

Non-human primates have constituted an important group among animals subjected to various studies. Ethological, evolutionary and paleontological studies have revealed changes in anatomical structures linked to the evolution of primates, considered in studies on the comparative anatomy between Cebus libidinosus and other neotropical monkeys or those from the Old World, and the detailed knowledge on their anatomy may represent an important factor for their preservation and protection when the animals are brought to veterinary clinics after accidents or illnesses. In terms of veterinary importance, sometimes these animals arrive in the veterinary medical clinics after accidents, needing surgery or clinical treatment, but the little data available on anatomy has impaired the correct proceedings. The main justification for studies on C. libidinosus, is due to little information about the anatomy related to C. libidinosus in Brazilian and worldwide scientific literature. In this study, the distribution, enervation and path of the femoral and sciatic nerves of the pelvic limb (thigh) of C. libidinosus were studied and these results were compared with literature on the anatomy of humans, chimpanzees and baboons. In general, the enervation model of the four primates is identical, but in specific terms, the differences in enervations indicate evolution convergence closer to the branch of baboons in the evolutionary tree, and these data corroborate other comparative studies in relation to the same primates to vessels, muscles and nerves. In conclusion, the nerve organization in the thigh of C. libidinosus is identical to baboon, chimpanzee and homo, but more similar to baboon. The specific differences found indicate an ancient phylogenic origin to C. libidinosus and baboons (data corroborated by other studies).

Age and species related variation in the development of growth plates of the knee and implications for the locomotion of Australopithecus afarensis

Comprendre l'évolution de la bipédie est un élément essentiel à la recherche en paléoanthropologie, car ce comportement est le trait le plus important utilisé pour identifier les fossiles comme appartenant à la lignée des hominines. La topographie de la surface infradiaphysaire du fémur et du tibia pourrait donner un aperçu du comportement locomoteur des espèces fossiles, mais n'a pas été étudiée de façon approfondie. Ce trait reflète directement les différences dans la locomotion, puisque la surface change de topographie pour mieux résister aux charges encourues par les mouvements réguliers. Le plan infradiaphysaire du fémur chez les humain est relativement plat, tandis que la surface est plus irrégulière chez les grands singes. Dans ce projet, les métaphyses du genou ont été étudiées d’une manière quantifiée afin de percevoir les différences entre espèces et mieux comprendre le développement ontogénique de ces traits. Les angles formés par les protrusions et les creux de ces surfaces ont été mesurés à partir de points de repère enregistrés en trois-dimensions sur les métaphyses du genou chez les humains, chimpanzés, gorilles, et orangs-outans, et chez trois fossiles Australopithecus afarensis, afin d’observer de l’effet de facteurs tel le stade de croissance et l’appartenance à une espèce sur la topographie des plaques de croissance du genou. Les angles d’obliquité du fémur et du tibia ont aussi été mesurés et analysés. Les résultats ont révélé que le stade développemental et l’appartenance à une espèce et, par association, le mode de locomotion, ont un effet significatif sur les métaphyses du genou. Il a également été constaté que les mesures d'Australopithecus afarensis chevauchent les valeurs trouvées chez les humains et chez les grands singes, ce qui suggère que cette espèce avait possiblement conservé une composante arboricole dans son comportement locomoteur habituel.

Working memory and working attention: What could possibly evolve?

The concept of “working” memory is traceable back to nineteenth century theorists (Baldwin, 1894; James 1890) but the term itself was not used until the mid-twentieth century (Miller, Galanter & Pribram, 1960). A variety of different explanatory constructs have since evolved which all make use of the working memory label (Miyake & Shah, 1999). This history is briefly reviewed and alternative formulations of working memory (as language-processor, executive attention, and global workspace) are considered as potential mechanisms for cognitive change within and between individuals and between species. A means, derived from the literature on human problem-solving (Newell & Simon, 1972), of tracing memory and computational demands across a single task is described and applied to two specific examples of tool-use by chimpanzees and early hominids. The examples show how specific proposals for necessary and/or sufficient computational and memory requirements can be more rigorously assessed on a task by task basis. General difficulties in connecting cognitive theories (arising from the observed capabilities of individuals deprived of material support) with archaeological data (primarily remnants of material culture) are discussed.

Evolutionary relationships of "candidatus riesia spp.," endosymbiotic enterobacteriaceae living within hematophagous primate lice

The primary endosymbiotic bacteria from three species of parasitic primate lice were characterized molecularly. We have confirmed the characterization of the primary endosymbiont (P-endosymbiont) of the human head/body louse Pediculus humanus and provide new characterizations of the P-endosymbionts from Pediculus schaeffi from chimpanzees and Pthirus pubis, the pubic louse of humans. The endosymbionts show an average percent sequence divergence of 11 to 15% from the most closely related known bacterium "Candidatus Arsenophonus insecticola." We propose that two additional species be added to the genus "Candidatus Riesia." The new species proposed within "Candidatus Riesia" have sequence divergences of 3.4% and 10 to 12% based on uncorrected pairwise differences. Our Bayesian analysis shows that the branching pattern for the primary endosymbionts was the same as that for their louse hosts, suggesting a long coevolutionary history between primate lice and their primary endosymbionts. We used a calibration of 5.6 million years to date the divergence between endosymbionts from human and chimpanzee lice and estimated an evolutionary rate of nucleotide substitution of 0.67% per million years, which is 15 to 30 times faster than previous estimates calculated for Buchnera, the primary endosymbiont in aphids. Given the evidence for cospeciation with primate lice and the evidence for fast evolutionary rates, this lineage of endosymbiotic bacteria can be evaluated as a fast-evolving marker of both louse and primate evolutionary histories.

Distribution of potential suitable hammers and transport of hammer tools and nuts by wild capuchin monkeys

Selection and transport of objects to use as tools at a distant site are considered to reflect planning. Ancestral humans transported tools and tool-making materials as well as food items. Wild chimpanzees also transport selected hammer tools and nuts to anvil sites. To date, we had no other examples of selection and transport of stone tools among wild nonhuman primates. Wild bearded capuchins (Cebus libidinosus) in Boa Vista (Piaui, Brazil) routinely crack open palm nuts and other physically well-protected foods on level surfaces (anvils) using stones (hammers) as percussive tools. Here we present indirect evidence, obtained by a transect census, that stones suitable for use as hammers are rare (study 1) and behavioral evidence of hammer transport by twelve capuchins (study 2). To crack palm nuts, adults transported heavier and harder stones than to crack other less resistant food items. These findings show that wild capuchin monkeys selectively transport stones of appropriate size and hardness to use as hammers, thus exhibiting, like chimpanzees and humans, planning in tool-use activities.