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Science (New York, N.Y.) Nov 2023Cooperation beyond familial and group boundaries is core to the functioning of human societies, yet its evolution remains unclear. To address this, we examined grooming,...
Cooperation beyond familial and group boundaries is core to the functioning of human societies, yet its evolution remains unclear. To address this, we examined grooming, coalition, and food-sharing patterns in bonobos (), one of our closest living relatives whose rare out-group tolerance facilitates interaction opportunities between groups. We show that, as in humans, positive assortment supports bonobo cooperation across borders. Bonobo cooperative attitudes toward in-group members informed their cooperative relationships with out-groups, in particular, forming connections with out-group individuals who also exhibited high cooperation tendencies. Our findings show that cooperation between unrelated individuals across groups without immediate payoff is not exclusive to humans and suggest that such cooperation can emerge in the absence of social norms or strong cultural dispositions.
Topics: Animals; Humans; Grooming; Pan paniscus; Pan troglodytes; Group Processes; Cooperative Behavior; Social Norms
PubMed: 37972165
DOI: 10.1126/science.adg0844 -
Nature Ecology & Evolution Sep 2023Archaic admixture has had a substantial impact on human evolution with multiple events across different clades, including from extinct hominins such as Neanderthals and...
Archaic admixture has had a substantial impact on human evolution with multiple events across different clades, including from extinct hominins such as Neanderthals and Denisovans into modern humans. In great apes, archaic admixture has been identified in chimpanzees and bonobos but the possibility of such events has not been explored in other species. Here, we address this question using high-coverage whole-genome sequences from all four extant gorilla subspecies, including six newly sequenced eastern gorillas from previously unsampled geographic regions. Using approximate Bayesian computation with neural networks to model the demographic history of gorillas, we find a signature of admixture from an archaic 'ghost' lineage into the common ancestor of eastern gorillas but not western gorillas. We infer that up to 3% of the genome of these individuals is introgressed from an archaic lineage that diverged more than 3 million years ago from the common ancestor of all extant gorillas. This introgression event took place before the split of mountain and eastern lowland gorillas, probably more than 40 thousand years ago and may have influenced perception of bitter taste in eastern gorillas. When comparing the introgression landscapes of gorillas, humans and bonobos, we find a consistent depletion of introgressed fragments on the X chromosome across these species. However, depletion in protein-coding content is not detectable in eastern gorillas, possibly as a consequence of stronger genetic drift in this species.
Topics: Animals; Humans; Gorilla gorilla; Pan paniscus; Bayes Theorem; Hominidae; Pan troglodytes; Neanderthals
PubMed: 37500909
DOI: 10.1038/s41559-023-02145-2 -
Journal of Biomechanics Aug 2023Motion analysis, as applied to evolutionary biomechanics, has experienced its own evolution over the last 50 years. Here we review how an ever-increasing fossil record,... (Review)
Review
Motion analysis, as applied to evolutionary biomechanics, has experienced its own evolution over the last 50 years. Here we review how an ever-increasing fossil record, together with continuing advancements in biomechanics techniques, have shaped our understanding of the origin of upright bipedal walking. The original, and long-established hypothesis held by Lamarck (1809), Darwin (1859) and Keith (1934), amongst others, maintained that bipedality originated in an arboreal context. However, the first field studies of gorilla and chimpanzees from the 1960's, highlighted their so-called 'knucklewalking' quadrupedalism, leading scientists to assume, semi-automatically, that knucklewalking must have been the precursor to bipedality. It would not be until the discovery of skeletons of early human relatives Australopithecus afarensis and Australopithecus prometheus, and the inclusion of methods of analysis from computer science, biomechanics, sports science and medicine, that the knucklewalking hypothesis would be most robustly challenged. Their short, but human-like lower limbs and human-like hand indicated that knucklewalking was not part of our ancestral locomotor repertoire. Rather, most current research in evolutionary biomechanics agrees it was a combination of climbing and bipedalism, both in an arboreal context, which facilitated upright, terrestrial, bipedal walking over short distances.
Topics: Animals; Humans; Biomechanical Phenomena; Walking; Pan troglodytes; Biological Evolution; Locomotion
PubMed: 37451208
DOI: 10.1016/j.jbiomech.2023.111701 -
Nature Immunology Mar 2024A nasally delivered chimpanzee adenoviral-vectored severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine (ChAd-SARS-CoV-2-S) is currently used in India...
A nasally delivered chimpanzee adenoviral-vectored severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine (ChAd-SARS-CoV-2-S) is currently used in India (iNCOVACC). Here, we update this vaccine by creating ChAd-SARS-CoV-2-BA.5-S, which encodes a prefusion-stabilized BA.5 spike protein. Whereas serum neutralizing antibody responses induced by monovalent or bivalent adenoviral vaccines were poor against the antigenically distant XBB.1.5 strain and insufficient to protect in passive transfer experiments, mucosal antibody and cross-reactive memory T cell responses were robust, and protection was evident against WA1/2020 D614G and Omicron variants BQ.1.1 and XBB.1.5 in mice and hamsters. However, depletion of memory CD8 T cells before XBB.1.5 challenge resulted in loss of protection against upper and lower respiratory tract infection. Thus, nasally delivered vaccines stimulate mucosal immunity against emerging SARS-CoV-2 strains, and cross-reactive memory CD8 T cells mediate protection against lung infection by antigenically distant strains in the setting of low serum levels of cross-reactive neutralizing antibodies.
Topics: Cricetinae; Animals; Mice; CD8-Positive T-Lymphocytes; SARS-CoV-2; COVID-19; Respiratory Tract Infections; Vaccines; Antibodies, Neutralizing; Broadly Neutralizing Antibodies; Pan troglodytes
PubMed: 38337035
DOI: 10.1038/s41590-024-01743-x -
Science (New York, N.Y.) Nov 2023Bonobos provide insight into the origins of partner-specific cooperation in human groups.
Bonobos provide insight into the origins of partner-specific cooperation in human groups.
Topics: Animals; Humans; Pan paniscus; Pan troglodytes; Mass Behavior; Cooperative Behavior; Grooming
PubMed: 37972176
DOI: 10.1126/science.adl1813 -
Scientific Reports Oct 2023Every evening, chimpanzees build sleeping "nests" in trees. In some studied communities, individuals appear to be selective about the tree species used, which has led...
Every evening, chimpanzees build sleeping "nests" in trees. In some studied communities, individuals appear to be selective about the tree species used, which has led researchers to hypothesize whether chimpanzees prefer trees that repel troublesome insects or/and that provide comfortable and stable structures. We investigate these hypotheses, or a trade-off between both, though study of tree species preference based on their biomechanical and/or biochemical properties in the Sebitoli chimpanzee community in Kibale National Park, Uganda. The ten tree species most frequently used for nesting were compared with ten abundant in their environment but not preferred for nesting. For these 20 tree species, we determined their biomechanical and morphological characteristics such as foliar density, foliar units form (shape and size) and branch rigidity. Their spatial repellent activity, previously tested against Anopheles gambiae was incorporated into the analysis. Chimpanzees chose tree species with medium-sized and elongated foliar units, high foliar density and branch with stiffer wood. In addition, most tree species with such mechanical and morphological properties also have mosquito repellent activity. These tree properties may provide a comfortable sleeping environment enhancing sleep quality. Finally, a comparison across chimpanzee communities would be relevant to understand whether these choices are not only ecological but also cultural.
Topics: Humans; Animals; Trees; Pan troglodytes; Sleep; Sleep Quality; Uganda; Nesting Behavior
PubMed: 37805595
DOI: 10.1038/s41598-023-44192-6 -
Journal of Human Evolution Aug 2023Since the launch of the Journal of Human Evolution fifty years ago, the archaeology of human origins and the evolution of culture have witnessed major breakthroughs with... (Review)
Review
Since the launch of the Journal of Human Evolution fifty years ago, the archaeology of human origins and the evolution of culture have witnessed major breakthroughs with the identification of several new archaeological sites whose chronology has been slowly pushed back until the discovery of the earliest evidence of stone tool making at Lomekwi 3 (West Turkana, Kenya), at 3.3 Ma. Parallel to these discoveries, the study of wild primates, especially chimpanzees (Pan troglodytes), allowed the development of models to understand key aspects of the behavior of extinct hominin species. Indeed, chimpanzees possess an impressive diversity of tool-aided foraging behaviors, demonstrating that technology (and culture) is not exclusive to humans. Additionally, current research has also shown that wild capuchin monkeys (Sapajus libidinosus) and long-tailed macaques (Macaca fascicularis) also rely on stone percussive foraging behaviors. The investigation of these primates is boosting new interpretative models to understand the origins of stone flaking and the archaeological signature left by these primates. This review aims to present an examination of the state-of-the-art and the current advances made in the study of the earliest hominin technology and primate percussive behaviors. Overall, we argue that while it has been shown that extant primates can generate unintentional flakes, early hominins exhibited skills in the production and use of flakes not identified in primates. Nonetheless, we stand up to continue developing interdisciplinary approaches (i.e., primate archaeology) to study extant primates, as these endeavors are essential to move forward toward a detailed understanding of the technological foraging behaviors beyond the genus Homo. Finally, we discuss future challenges for the study of the emergence of stone technology.
Topics: Animals; Humans; Archaeology; Pan troglodytes; Biological Evolution; Tool Use Behavior; Hominidae; Cebus
PubMed: 37329870
DOI: 10.1016/j.jhevol.2023.103398 -
The Veterinary Record Nov 2023Georgina Mills discusses new research that investigates if the hormonal changes seen in women in later life are reflected in chimpanzees.
Georgina Mills discusses new research that investigates if the hormonal changes seen in women in later life are reflected in chimpanzees.
Topics: Female; Animals; Pan troglodytes; Menopause
PubMed: 37975459
DOI: 10.1002/vetr.3683 -
The Lancet. Infectious Diseases Dec 2023Sudan Ebola virus can cause severe viral disease, with an average case fatality rate of 54%. A recent outbreak of Sudan Ebola virus in Uganda caused 55 deaths among 164...
Safety, tolerability, and immunogenicity of the Ebola Sudan chimpanzee adenovirus vector vaccine (cAd3-EBO S) in healthy Ugandan adults: a phase 1, open-label, dose-escalation clinical trial.
BACKGROUND
Sudan Ebola virus can cause severe viral disease, with an average case fatality rate of 54%. A recent outbreak of Sudan Ebola virus in Uganda caused 55 deaths among 164 confirmed cases in the second half of 2022. Although vaccines and therapeutics specific for Zaire Ebola virus have been approved for use during outbreak situations, Sudan Ebola virus is an antigenically distinct virus with no approved vaccines available.
METHODS
In this phase 1, open-label, dose-escalation trial we evaluated the safety, tolerability, and immunogenicity of a monovalent chimpanzee adenovirus 3 vaccine against Sudan Ebola virus (cAd3-EBO S) at Makerere University Walter Reed Project in Kampala, Uganda. Study participants were recruited from the Kampala metropolitan area using International Review Board-approved written and electronic media explaining the trial intervention. Healthy adults without previous receipt of Ebola, Marburg, or cAd3 vectored-vaccines were enrolled to receive cAd3-EBO S at either 1 × 10 or 1 × 10 particle units (PU) in a single intramuscular vaccination and were followed up for 48 weeks. Primary safety and tolerability endpoints were assessed in all vaccine recipients by reactogenicity for the first 7 days, adverse events for the first 28 days, and serious adverse events throughout the study. Secondary immunogenicity endpoints included evaluation of binding antibody and T-cell responses against the Sudan Ebola virus glycoprotein, and neutralising antibody responses against the cAd3 vector at 4 weeks after vaccination. This study is registered with ClinicalTrials.gov, NCT04041570, and is completed.
FINDINGS
40 healthy adults were enrolled between July 22 and Oct 1, 2019, with 20 receiving 1 × 10 PU and 20 receiving 1 × 10 PU of cAd3-EBO S. 38 (95%) participants completed all follow-up visits. The cAd3-EBO S vaccine was well tolerated with no severe adverse events. The most common reactogenicity symptoms were pain or tenderness at the injection site (34 [85%] of 40), fatigue (29 [73%] of 40), and headache (26 [65%] of 40), and were mild to moderate in severity. Positive responses for glycoprotein-specific binding antibodies were induced by 2 weeks in 31 (78%) participants, increased to 34 (85%) participants by 4 weeks, and persisted to 48 weeks in 31 (82%) participants. Most participants developed glycoprotein-specific T-cell responses (20 [59%, 95% CI 41-75] of 34; six participants were removed from the T cell analysis after failing quality control parameters) by 4 weeks after vaccination, and neutralising titres against the cAd3 vector were also increased from baseline (90% inhibitory concentration of 47, 95% CI 30-73) to 4 weeks after vaccination (196, 125-308).
INTERPRETATION
The cAd3-EBO S vaccine was safe at both doses, rapidly inducing immune responses in most participants after a single injection. The rapid onset and durability of the vaccine-induced antibodies make this vaccine a strong candidate for emergency deployment in Sudan Ebola virus outbreaks.
FUNDING
National Institutes of Health via interagency agreement with Walter Reed Army Institute of Research.
Topics: Animals; Humans; Adult; Hemorrhagic Fever, Ebola; Ebola Vaccines; Pan troglodytes; Uganda; Sudan; Ebolavirus; Antibodies, Viral; Adenoviruses, Simian; Adenoviridae; Glycoproteins; Immunogenicity, Vaccine; Double-Blind Method
PubMed: 37544326
DOI: 10.1016/S1473-3099(23)00344-4 -
Royal Society Open Science Sep 2023The forelimbs of hominoid primates (apes) are decidedly more flexible than those of monkeys, especially at the shoulder, elbow and wrist joints. It is tempting to link...
The forelimbs of hominoid primates (apes) are decidedly more flexible than those of monkeys, especially at the shoulder, elbow and wrist joints. It is tempting to link the greater mobility of these joints to the functional demands of vertical climbing and below-branch suspension, but field-based kinematic studies have found few differences between chimpanzees and monkeys when comparing forelimb excursion angles during vertical ascent (upclimbing). There is, however, a strong theoretical argument for focusing instead on vertical descent (downclimbing), which motivated us to quantify the effects of climbing directionality on the forelimb kinematics of wild chimpanzees () and sooty mangabeys (). We found that the shoulders and elbows of chimpanzees and sooty mangabeys subtended larger joint angles during bouts of downclimbing, and that the magnitude of this difference was greatest among chimpanzees. Our results cast new light on the functional importance of downclimbing, while also burnishing functional hypotheses that emphasize the role of vertical climbing during the evolution of apes, including the human lineage.
PubMed: 37680499
DOI: 10.1098/rsos.230145