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Hybrids between common chimpanzees (Pan troglodytes) and pygmy chimpanzees (Pan paniscus) in captivity
... This appears to be the upper limit of mtDNA variation between members of the genus Pan. Despite their reproductive and morphological differences, chimpanzees and bonobos can hybridize in captivity (Vervaecke and Van Elsacker, 1992), and there is evidence of introgression of a small portion of nuclear genetic material between the two species based on a study of 75 wild-born chimpanzees and bonobos (de Manuel et al., 2016). The MSS variation of Homo seen in Fig. 2A To illustrate relationships within the human clade, a phylogenetic tree was created using the MEGA-X software shown in Fig. 3. ...
Mitochondrial and nuclear DNA isolated from the fossils of Homo heidelbergensis are a real godsend. Morphological assessments of a given fossil can be highly subjective, sometimes having to transfer species from Homo to Australopithecus. However, sequencing data makes the accurate genetic reassessment of this fossil among primates possible.
The mtDNA for 36 primates including Neanderthal, Denisovan, and Homo heidelbergensis were downloaded from NCBI and aligned and visualized in a heat map. Homo heidelbergensis appears to be a member of the human clade, separating sharply from all other primates. Comparisons between 21 modern humans, three archaic humans, and three Pan sequences show that archaic humans fit within the variation of modern humans, meaning that together with Neanderthal and Denisovans, Homo heidelbergensis is also part of the human clade.
Reads from nine Homo heidelbergensis SRAs were downloaded from BioProject PRJEB10957 and ten for an archaic human from PRJEB22592. These reads were mapped to the hg38, the Neanderthal, and the panTro6 genomes, and variants were called using the samtools pipeline. The same proportion of reads mapped to hg38 as did from the archaic human genome, and more than to panTro6. Furthermore, the variant density was also the same between Homo heidelbergensis and archaic human, when mapping to hg38. BLASTing read sequences against hg38 and panTro6 gave similar results. Finally, the proportion of C > T/G > A point mutations in Homo heidelbergensis (40.1%) was statistically significantly greater than in modern human (33.2%). This indicates that 6.9% of these mutations stem from deamination.
Homo heidelbergensis genetically behaves very much like archaic human, and thus can be considered to be human, just like Neanderthal and Denisovan. It would be of tremendous value if either mtDNA and/or nuclear DNA could be found in the fossils of other hominids so as to make a more precise assessment of human phylogenetics possible.
... . Further, some gene flow is hard to reconcile with present Pan biogeography. Bonobos and chimpanzees can hybridize in captivity(30), but wild populations are completely separated by Fitted autosomal model residuals. We display the worst-fit model, an average model, and the best-fit model. ...
Significance
There is genomic evidence of widespread admixture in deep time between many closely related species, including humans. Our closest living relatives, bonobos and chimpanzees, may also exhibit such patterns. However, assessing the exact degree of interbreeding remains challenging because previous studies have resulted in multiple inconsistent demographic models. We use an approach that addresses these gaps by analyzing all lineages, simultaneously estimating parameters, and comparing previously models. We find evidence of considerable introgression from western into eastern chimpanzees. We also show more breeding females than males and evidence of male-biased dispersal in western chimpanzees. These findings highlight the extent of admixture in bonobo and chimpanzee evolutionary history and are consistent with substantial differences between past and present chimpanzee biogeography.
... troglodytes), have been long studied for genomic signatures of admixture. These species can hybridize in captivity (Vervaecke and Van Elsacker 1992), but wild populations are completely separated by the Congo River that may be difficult to traverse. Chimpanzees have been characterized as poor swimmers (Angus 1971) and as being afraid of water (Kano 1992), yet some populations enter bodies of water to forage (Watts et al. 2012a;Watts et al. 2012b) and thermoregulate in hot, dry habitats (Pruetz and Bertolani 2009). ...
Introgression appears increasingly ubiquitous in the evolutionary history of various taxa, including humans. However, accurately estimating introgression is difficult, particularly when 1) there are many parameters, 2) multiple models fit the data well, and 3) parameters are not simultaneously estimated. Here, we use the software Legofit to investigate the evolutionary history of bonobos (Pan paniscus) and chimpanzees (P. troglodytes) using whole genome sequences. This approach 1) ignores within-population variation, reducing the number of parameters requiring estimation, 2) allows for model selection, and 3) simultaneously estimates all parameters. We tabulated site patterns from the autosomes of 71 bonobos and chimpanzees representing all five extant Pan lineages. We then compared previously proposed demographic models and estimated parameters using a deterministic approach. We further considered sex bias in Pan evolutionary history by analyzing the site patterns from the X chromosome. Introgression from bonobos into the ancestor of eastern and central chimpanzees and from western into eastern chimpanzees best explained the autosomal site patterns. This second event was substantial with an estimated 0.21 admixture proportion. Estimates of effective population size and most divergence dates are consistent with previous findings; however, we observe a deeper divergence within chimpanzees at 987 ka. Finally, we identify male-biased reproduction in Pan evolutionary history and suggest that western to eastern chimpanzee introgression was driven by western males mating with eastern females.
... However, there is evidence that some genes would have entered the "pure" species on both sides, with exchanges occurring at the time of hybridization (Arntzen and Wallis 1991). In primates there are also several cases of hybridization (Arnold and Meyer 2006), reported among New World Monkeys, as identified in Saimiri species (Carneiro et al. 2016;Mourthe et al. 2019) as well as in Old World Monkeys, as Pan troglodytes and Pan paniscus (Vervaecke and Elsacker 1992;de Manuel et al. 2016). ...
Genetic studies have presented increasing indications about the complexity of the interactions between Homo sapiens , Neanderthals and Denisovans, during Pleistocene. The results indicate potential replacement or admixture of the groups of hominins that lived in the same region at different times. Recently, the time of separation among these hominins in relation to the Last Common Ancestor – LCA has been reasonably well established. Events of mixing with emphasis on the Neanderthal gene flow into H. sapiens outside Africa, Denisovans into H. sapiens ancestors in Oceania and continental Asia, Neanderthals into Denisovans, as well as the origin of some phenotypic features in specific populations such as the color of the skin, eyes, hair and predisposition to develop certain kinds of diseases have also been found. The current information supports the existence of both replacement and interbreeding events, and indicates the need to revise the two main explanatory models, the Multiregional and the Out-of-Africa hypotheses, about the origin and evolution of H. sapiens and its co-relatives. There is definitely no longer the possibility of justifying only one model over the other. This paper aims to provide a brief review and update on the debate around this issue, considering the advances brought about by the recent genetic as well as morphological traits analyses.
Cell fusions have a long history of supporting biomedical research. These experimental models, historically referred to as 'somatic cell hybrids', involve combining the plasma membranes of two cells and merging their nuclei within a single cytoplasm. Cell fusion studies involving human and chimpanzee pluripotent stem cells, rather than somatic cells, highlight the need for responsible communication and a revised nomenclature. Applying the terms 'hybrid' and 'parental' to the fused and source cell lines, respectively, evokes reproductive relationships that do not exist between humans and other species. These misnomers become more salient in the context of fused pluripotent stem cells derived from different but closely related species. Here, we propose a precise, versatile and generalizable framework to describe these fused cell lines. We recommend the term 'composite cell line', to distinguish cell lines that are experimentally created through fusions from both reproductive hybrids and natural cell fusion events without obscuring the model in overly technical terms. For scientific audiences, we further recommend technical nomenclature that describes the contributing species, ploidy and cell type.
RESUME. Le bonobo (Pan paniscus) est la dernière espèce de primates anthropoïdes à avoir émergé sur la scène publique occidentale. Nous tentons ici de comprendre comment il a commencé à exister aux yeux de la communauté scientifique, puis comment il a traversé de manière dynamique et féconde différents champs, suscitant de nouvelles interrogations et des propositions inédites. Au cours de cette exploration, nous rencontrerons différents acteurs des réseaux tissés autour de la « découverte » du chimpanzé pygmée et nous nous efforcerons de montrer sous quels régimes de savoir et accompagné de quels attributs il est peu à peu entré dans les discours scientifiques occidentaux. Cette approche historique et anthropologique du bonobo devrait nous permettre de mieux saisir une « primatologie » en train de se faire, les liens entre primatologie et politique coloniale occidentale, ainsi que l'importance des collections d'histoire naturelle en primatologie. ABSTRACT. The Pygmy Chimpanzee (Pan paniscus) is the last species of anthropoid primates to have emerged in the eyes of the Western public. In this paper, I try to understand how it started to exist in the mind of the scientific community, and how it passed dynamically through different fields, arousing new questions and generative hypothesis. All along this study, I encounter different agents of webs weaved around the "discovery" of the Pygmy Chimpanzee and I try to demonstrate under which types of knowledge and with which attributes, it has little by little entered the western scientific discourse. This historical and anthropological approach of the Pygmy Chimpanzee should lead us to a better understanding of a "primatology in progress", the relationship between primatology and Western colonial politics, and the importance of natural history collections in primatology.
China has historically been a proving ground for alternative hypotheses of hominan* evolution. During the mid 20th century its human fossil record was touted as persuasive evidence for a model of genetic continuity across grade transitions, culminating in the emergence of modern humans in regional contexts. More recently, the same record has been posited as evidence for the replacement of regionally dispersed archaic humans by African derived anatomically modern Homo sapiens. There is, however, yet another perspective. It proposes that the evolution of the genus
This is a 133-page bibliography listing a wide variety of published works bearing on the topic of mammalian hybridization. More than 2,300 publications are listed.
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