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Biology Letters Jun 2024When chimpanzees search for hidden food, do they realize that their guesses may not be correct? We applied a post-decision wagering paradigm to a simple two-cup search...
When chimpanzees search for hidden food, do they realize that their guesses may not be correct? We applied a post-decision wagering paradigm to a simple two-cup search task, varying whether we gave participants visual access to the baiting and then asking after they had chosen one of the cups whether they would prefer a smaller but certain reward instead of their original choice (experiment 1). Results showed that chimpanzees were more likely to accept the smaller reward in occluded than visible conditions. Experiment 2 found the same effect when we blocked visual access but manipulated the number of hiding locations for the food piece, showing that the effect is not owing to representation type. Experiments 3 and 4 showed that when given information about the contents of the unchosen cup, chimpanzees were able to flexibly update their choice behaviour accordingly. These results suggest that language is not a pre-requisite to solving the disjunctive syllogism and provides a valuable contribution to the debate on logical reasoning in non-human animals.
Topics: Animals; Pan troglodytes; Male; Female; Choice Behavior; Reward
PubMed: 38863345
DOI: 10.1098/rsbl.2024.0051 -
Nature Methods Jun 2024Long-standing questions about human brain evolution may only be resolved through comparisons with close living evolutionary relatives, such as chimpanzees. This applies...
Long-standing questions about human brain evolution may only be resolved through comparisons with close living evolutionary relatives, such as chimpanzees. This applies in particular to structural white matter (WM) connectivity, which continuously expanded throughout evolution. However, due to legal restrictions on chimpanzee research, neuroscience research currently relies largely on data with limited detail or on comparisons with evolutionarily distant monkeys. Here, we present a detailed magnetic resonance imaging resource to study structural WM connectivity in the chimpanzee. This open-access resource contains (1) WM reconstructions of a postmortem chimpanzee brain, using the highest-quality diffusion magnetic resonance imaging data yet acquired from great apes; (2) an optimized and validated method for high-quality fiber orientation reconstructions; and (3) major fiber tract segmentations for cross-species morphological comparisons. This dataset enabled us to identify phylogenetically relevant details of the chimpanzee connectome, and we anticipate that it will substantially contribute to understanding human brain evolution.
Topics: Pan troglodytes; Animals; White Matter; Brain; Connectome; Male; Neural Pathways; Image Processing, Computer-Assisted; Female; Brain Mapping
PubMed: 38831210
DOI: 10.1038/s41592-024-02270-1 -
Nature Methods Jun 2024
Topics: Animals; Pan troglodytes; White Matter; Diffusion Magnetic Resonance Imaging; Brain; Connectome; Image Processing, Computer-Assisted
PubMed: 38831209
DOI: 10.1038/s41592-024-02271-0 -
American Journal of Biological... Jun 2024Chimpanzees (Pan troglodytes) are patrilocal, with males remaining in their natal community and females dispersing when they reach sexual maturity. However, the details...
OBJECTIVES
Chimpanzees (Pan troglodytes) are patrilocal, with males remaining in their natal community and females dispersing when they reach sexual maturity. However, the details of female chimpanzee dispersal, such as their possible origin, are difficult to assess, even in habituated communities. This study investigates the utility of Sr/Sr analysis for (1) assessing Sr baseline differences between chimpanzee territories and (2) identifying the status (immigrant or natal) of females of unknown origin within the territories of five neighboring communities in Taï National Park (Côte d'Ivoire).
MATERIALS AND METHODS
To create a local Sr isoscape for the Taï Chimpanzee Project (TCP) study area, we sampled environmental samples from TCP-established territories (n = 35). To assess dispersal patterns, 34 tooth enamel samples (one per individual) were selected from the Taï chimpanzee skeletal collection. Sr/Sr analysis was performed on all 69 samples at the W.M. Keck Lab. The theoretical density and overlap of chimpanzee communities as well as generalized linear mixed models (GLMMs) were used to test each question.
RESULTS
Sr/Sr ratios for natal male chimpanzees ranged from 0.71662 to 0.72187, which is well within the corresponding environmental baseline range of 0.70774-0.73460. The local Sr isoscapes fit was estimated with the root-mean-square error value, which was 0.0048 (22% of the whole Sr/Sr data range). GLMMs identified significant differences in Sr/Sr ratios between natal and unknown North community origin groups, suggesting that after 1980, females of unknown origin could be immigrants to North community (n = 7, z-ratio = -4.08, p = 0.0001, power = 0.94).
DISCUSSION
This study indicates that Sr/This study indicates that Sr/Sr analysis can successfully identify immigrant females in skeletal collections obtained from wild chimpanzee communities, enabling the tracking of female dispersal patterns historically. There are, however, significant limitations within the scope of this study, such as (1) the absence of reliable maps for the TCP study area, (2) limited capacity for environmental sampling, (3) small sample sizes, and (4) tooth formation in wild chimpanzees.
PubMed: 38828504
DOI: 10.1002/ajpa.24981 -
International Journal For Parasitology.... Aug 2024Intestinal protozoa, which can be asymptomatic or cause diarrhea, dysentery and even death, are among the main agents that affect nonhuman primates (NHPs) kept under...
Intestinal protozoa, which can be asymptomatic or cause diarrhea, dysentery and even death, are among the main agents that affect nonhuman primates (NHPs) kept under human care. Nevertheless, information on the molecular and morphometric profiles of parabasilids in the Neotropics is still scarce. In this context, the objective of this study was to isolate the Parabasalia protozoa detected in the feces of NHPs and their keepers in Pavlova and TYSGM9 media and to characterize the isolates by molecular biology and morphometry. Fecal samples from NHPs from five Brazilian institutions were analyzed. Direct examination was performed immediately after obtaining the samples. A total of 511 fecal samples from NHPs were collected, and 10.6% contained parabasilids. Regarding the handlers, of the 74 samples analyzed, three were positive. In vitro-generated parabasilid isolates were successfully obtained from all positive samples, as identified via microscopy. Isolates of the parasite were obtained both from New World NHPs, including the genera , , , , , , and and from the Old World primate . Forty-nine NHP isolates were molecularly identified: (16), (14), (13) and (6). The human isolates were identified as sp. (2) and (1). Visualization and morphometric analysis revealed trophozoites with piriform or rounded shapes that presented variable measurements. The isolates previously characterized as had up to five free flagella, while and sp. had up to four free flagella, and had a maximum of three free flagella. These morphometric characteristics corroborated the molecular identification. In general, a variety of parabasilids were observed to infect NHPs, and was isolated from biological samples from both NHPs and their keepers, a finding that reinforces the susceptibility of these hosts to infections by parabasilids in Brazil.
PubMed: 38827824
DOI: 10.1016/j.ijppaw.2024.100946 -
Frontiers in Genetics 2024Alport Syndrome (AS) is a genetic kidney disorder characterized by progressive hearing loss and atypical eye symptoms, resulting in a poor prognosis and lack of...
Alport Syndrome (AS) is a genetic kidney disorder characterized by progressive hearing loss and atypical eye symptoms, resulting in a poor prognosis and lack of effective targeted therapy. The primary mode of inheritance is X-linked dominant (XLAS) due to variants in the gene. This study revealed a previously unidentified alternative form of the gene, namely, the c.4822-10T>C variant, which was confirmed through experiments. To investigate the impact of a splicing variant on mRNA production, an minigene splicing assay was utilized. Additionally, molecular dynamics was employed to predict the ability of α5(IV) to form a triple helix. Results from the experiment revealed that the wild-type (WT) plasmid produced two distinct mRNA products simultaneously. Sequence analysis using the BLAST database revealed a 173-bp deletion in the mRNA sequence of the first product, indicating a potential similarity to the XM_016942897.2 transcript of . The second mRNA product of the WT plasmid contained the full sequence of exons 51, 52, and 53, as anticipated. Conversely, the mutant (MT) plasmid generated a single mRNA product with a 173-bp deletion in exon 52, leading to the identification of the mature mRNA expression as NM_033380.2: COL4A5: c.4822_4994del. In the context of nonsense-mediated mRNA decay (NMD), the deletion c.4822_4994 results in the production of a truncated protein, p.His1608*, that terminates prematurely. This truncated protein may disrupt the secondary structure of α5(IV) and potentially cause an abnormal conformation of α345(IV). This study examines the relationship between the variable splicing pattern in the NM_033380.2 transcript of the gene in XLAS patients and the presence of the gene splice variant c.4822-10T>C. Our findings indicate that the c.4822-10T>C splice variant leads to activation of nonsense-mediated mRNA degradation (NMD) and reduced mRNA expression, resulting in inadequate synthesis of the corresponding proteins. This aligns with the patient's immunofluorescence results showing negative α5(IV) chain presence at the glomerular basement membrane, bursa, and tubular basement membrane, confirming the pathogenic nature of c.4822-10T>C.
PubMed: 38818038
DOI: 10.3389/fgene.2024.1330525 -
Primates; Journal of Primatology May 2024Although chimpanzees (Pan troglodytes) and bonobos (Pan paniscus) share a multi-male/multi-female societal organization and form male-philopatric groups, disparities in...
Comparative analysis of intragroup intermale relationships: a study of wild bonobos (Pan paniscus) in Wamba, Democratic Republic of Congo and chimpanzees (Pan troglodytes) in Kalinzu Forest Reserve, Uganda.
Although chimpanzees (Pan troglodytes) and bonobos (Pan paniscus) share a multi-male/multi-female societal organization and form male-philopatric groups, disparities in terms of male aggression and stability of temporary parties are thought to exist among them. However, existing research in bonobos has mainly focused on the high social status, prolonged receptivity, and characteristic sexual behaviors of females, leaving the behaviors of males understudied. Moreover, prior comparative studies on Pan suffer from methodological inconsistencies. This study addresses these gaps by employing a uniform observation method to explore party attendance and aggressive interactions among male bonobos in Wamba and male chimpanzees in Kalinzu. Unlike male chimpanzees, which exhibit dispersion in the absence of receptive females in the group, male bonobos showed a lesser degree of such dispersion. Although the overall frequency of aggressive interactions per observation unit did not significantly differ between the two species, the nature of these interactions varied. Notably, severe aggressive behaviors such as physical confrontations among adult males were absent in bonobos, with most aggression occurring between the sons of the two highest-ranking females. Additionally, in bonobos, females actively engaged in polyadic aggressive behavior as aggressors, while all instances of coalitionary aggression in chimpanzees originated from male aggressors. These findings underscore the substantial impact of female behaviors on the observed distinctions in male aggressive interactions between the two species.
PubMed: 38816634
DOI: 10.1007/s10329-024-01134-8 -
Nature Jun 2024Apes possess two sex chromosomes-the male-specific Y chromosome and the X chromosome, which is present in both males and females. The Y chromosome is crucial for male... (Comparative Study)
Comparative Study
Apes possess two sex chromosomes-the male-specific Y chromosome and the X chromosome, which is present in both males and females. The Y chromosome is crucial for male reproduction, with deletions being linked to infertility. The X chromosome is vital for reproduction and cognition. Variation in mating patterns and brain function among apes suggests corresponding differences in their sex chromosomes. However, owing to their repetitive nature and incomplete reference assemblies, ape sex chromosomes have been challenging to study. Here, using the methodology developed for the telomere-to-telomere (T2T) human genome, we produced gapless assemblies of the X and Y chromosomes for five great apes (bonobo (Pan paniscus), chimpanzee (Pan troglodytes), western lowland gorilla (Gorilla gorilla gorilla), Bornean orangutan (Pongo pygmaeus) and Sumatran orangutan (Pongo abelii)) and a lesser ape (the siamang gibbon (Symphalangus syndactylus)), and untangled the intricacies of their evolution. Compared with the X chromosomes, the ape Y chromosomes vary greatly in size and have low alignability and high levels of structural rearrangements-owing to the accumulation of lineage-specific ampliconic regions, palindromes, transposable elements and satellites. Many Y chromosome genes expand in multi-copy families and some evolve under purifying selection. Thus, the Y chromosome exhibits dynamic evolution, whereas the X chromosome is more stable. Mapping short-read sequencing data to these assemblies revealed diversity and selection patterns on sex chromosomes of more than 100 individual great apes. These reference assemblies are expected to inform human evolution and conservation genetics of non-human apes, all of which are endangered species.
Topics: Animals; Female; Male; Gorilla gorilla; Hominidae; Hylobatidae; Pan paniscus; Pan troglodytes; Phylogeny; Pongo abelii; Pongo pygmaeus; Telomere; X Chromosome; Y Chromosome; Evolution, Molecular; DNA Copy Number Variations; Humans; Endangered Species; Reference Standards
PubMed: 38811727
DOI: 10.1038/s41586-024-07473-2 -
American Journal of Primatology May 2024Nematodes belonging to the genus Oesophagostomum frequently infect wild chimpanzees (Pan troglodytes) across widely separated field sites. Nodular lesions (granulomas)...
Nematodes belonging to the genus Oesophagostomum frequently infect wild chimpanzees (Pan troglodytes) across widely separated field sites. Nodular lesions (granulomas) containing Oesophagostomum are commonly seen in the abdomen of infected chimpanzees post-mortem. At Taï National Park, Côte d'Ivoire, previous studies have identified larvae of a variety of Oesophagostomum spp. in wild chimpanzee stool, based on sequencing of larval DNA, and nodular lesions associated with Oesophagostomum, identified morphologically to the genus level but not sequenced. Here we present three recent cases of parasitic granulomas found post-mortem in chimpanzees at Taï. We complement descriptions of gross pathology, histopathology and parasitology with PCR and sequencing of DNA isolated from the parasitic nodules and from adult worms found inside the nodules. In all three cases, we identify Oesophagostomum stephanostomum as the causative agent. The sequences from this study were identical to the only other published sequences from nodules in nonhuman primates-those from the wild chimpanzees of Gombe, Tanzania.
PubMed: 38807168
DOI: 10.1002/ajp.23652 -
Scientific Data May 2024Human and non-human primates have strikingly similar genomes, but they strongly differ in many brain-based processes (e.g., behaviour and cognition). While the functions...
Human and non-human primates have strikingly similar genomes, but they strongly differ in many brain-based processes (e.g., behaviour and cognition). While the functions of protein-coding genes have been extensively studied, rather little is known about the role of non-coding RNAs such as long non-coding RNAs (lncRNAs). Here, we predicted lncRNAs and analysed their expression pattern across different brain regions of human and non-human primates (chimpanzee, gorilla, and gibbon). Our analysis identified shared orthologous and non-orthologous lncRNAs, showing striking differences in the genomic features. Differential expression analysis of the shared orthologous lncRNAs from humans and chimpanzees revealed distinct expression patterns in subcortical regions (striatum, hippocampus) and neocortical areas while retaining a homogeneous expression in the cerebellum. Co-expression analysis of lncRNAs and protein-coding genes revealed massive proportions of co-expressed pairs in neocortical regions of humans compared to chimpanzees. Network analysis of co-expressed pairs revealed the distinctive role of the hub-acting orthologous lncRNAs in a region- and species-specific manner. Overall, our study provides novel insight into lncRNA driven gene regulatory landscape, neural regulation, brain evolution, and constitutes a resource for primate's brain lncRNAs.
Topics: Animals; Humans; Brain; Gorilla gorilla; Hylobates; Pan troglodytes; Primates; RNA, Long Noncoding; Species Specificity
PubMed: 38806530
DOI: 10.1038/s41597-024-03380-3