Dana Venditti Mitchell

The commercial trade in wild meat is booming in Central Africa. Addressing this issue is a global priority because the trade poses a major threat to biodiversity and human health. We investigated the impact of socioeconomic factors, public health emergencies, and conservation efforts on the wild meat trade using daily surveys of wild meat markets on Bioko Island, Equatorial Guinea (EG), from 1997 through 2021. Bioko is an ideal location for examining how external factors impact the wild meat market trade. Although small, the island has large areas of intact forest that host populations of commercially valuable wildlife; low-cost protein substitutes are available; and Malabo, the island’s only large metropolitan area and wild meat trading hub, hosts a wealthy class of urbanites. We found significant associations between global market trends and the wild meat trade, especially China’s foreign investment and oil production in the US and EG. Economic crises like EG’s 2009 economic downturn that followed a global crash in oil prices and reduced production, redirected demand towards cheaper mainland wildlife carcasses amid reduced consumer demand. Public health emergencies had the most comprehensive impact on the wild meat trade. The 2014 Ebola outbreak and the COVID-19 pandemic both induced shifts in market demand, and the COVID-19 pandemic disrupted trade routes, affecting both urban and rural markets. Internally, we observed market decentralization over the last decade and changes in wildlife supply chains during public health emergencies. Conservation policies, including anti-poaching measures and educational outreach, temporarily influenced wildlife market trends, sometimes leading to trading surges in endangered primate carcasses. Our study highlights the importance of monitoring global market trends, public health campaigns, and adapting conservation strategies to disrupt wildlife supply chains and curb consumer demand for wild meat.

Species evolve from populations with ancestor-descendant relationships in a bifurcating process shaped by geography, gene flow, genetic drift, and natural selection leading to local adaptation to prevailing environmental and ecological conditions. Building on this foundational understanding, we explored local adaptation in chimpanzees ( Pan troglodytes ) at a key geographical intersection in Cameroon where the two main chimpanzee phylogenetic lineages converge. The Nigeria-Cameroon chimpanzee ( P. t. ellioti ) and central chimpanzee ( P. t. troglodytes ) last shared a common ancestor about 500 thousand years ago, with occasional gene flow between them. The evolutionary processes driving their prolonged separation are not fully understood, but neutral evolutionary mechanisms alone cannot account for the observed divergence pattern. Cameroon is often referred to as ‘Africa in miniature’ because the Gulf of Guinea Forest, Congo Basin Forest, and savanna converge there, forming an ecotone. Thus, this contact zone between subspecies in Cameroon provides a unique natural laboratory that enabled us to investigate how environmental variation and natural selection shape divergence in chimpanzees. We developed a genome-wide panel of single-nucleotide polymorphisms (SNPs) in 112 wild chimpanzees sampled in multiple habitats across this contact zone. We augmented SNP discovery by sequencing eight new chimpanzee genomes from Cameroon and analyzing them with previously published chimpanzee genomes. We found that P. t. ellioti and P. t. troglodytes diverged from one another around 478,000 years ago and occasionally exchange migrants. We identified 1,690 unique SNPs across 905 genes associated with 31 environmental variables that describe the habitat. These genes are involved in essential biological processes, including immune response, neurological development, behavior, and dietary adaptations. This study highlights the importance of understanding the geographical context of natural selection, paving the way for future studies to interpret evidence for genetic variation with phenotypic traits and deepening our understanding of how populations diverge in response to environmental pressures. Author Summary: We investigated how local adaptation contributes to shaping the diversification of chimpanzee subspecies at the geographical convergence point for the two major branches of the chimpanzee phylogenetic tree. We analyzed genome-wide SNP genotypes of 112 chimpanzees sampled from natural communities located in this understudied area. We used tiered methods that identified 905 genes subject to selection, each associated with one or more of 31 environmental predictors describing the habitat. We found strong signals of selection in immune response genes that separate P. t. troglodytes from P. t. ellioti , highlighting the important role of different pathogen histories in their evolution. We also found evidence of selection in genes associated with neurological development, behavior, and diet, that separate both the subspecies and populations of P. t. ellioti that occupy different niches. These findings suggest that ecological and cultural factors may also contribute to shaping the diversification of chimpanzees across the contact zone.

Inflammation in the bone marrow (BM) microenvironment is a constitutive component of leukemogenesis in acute myeloid leukemia (AML). Current evidence suggests that both leukemic blasts and stroma secrete proinflammatory factors that actively suppress the function of healthy hematopoietic stem and progenitor cells (HSPCs). HSPCs are also cellular components of the innate immune system, and we reasoned that they may actively propagate the inflammation in the leukemic niche. In two separate congenic models of AML we confirm by evaluation of the BM plasma secretome and HSPC-selective single-cell RNA sequencing (scRNA-Seq) that multipotent progenitors and long-lived stem cells adopt inflammatory gene expression programs, even at low leukemic infiltration of the BM. In particular, we observe interferon gamma (IFN-γ) pathway activation, along with secretion of its chemokine target, CXCL10. We show that AML-derived nanometer-sized extracellular vesicles (EV^AML) are sufficient to trigger this inflammatory HSPC response, both in vitro and in vivo. Altogether, our studies indicate that HSPCs are an unrecognized component of the inflammatory adaptation of the BM by leukemic cells. The pro-inflammatory conversion and long-lived presence of HSPCs in the BM along with their regenerative re-expansion during remission may impact clonal selection and disease evolution.

Anthropogenic pressures, habitat alterations, and climate change threaten the world's biodiversity. The Gulf of Guinea and Congo Basin rainforests in Central Africa are a region of global biodiversity importance for several reasons: they are some of the largest remaining tracts of rainforest on the planet; they are home to a large portion of the world's known plant and animal species; and both regions host a rich retinue of endemic flora and fauna. Despite their importance, the regions are plagued by anthropogenic pressures, such as habitat loss, habitat alteration, hunting and other forms of resource exploitation. The impacts of these various pressures on the region's diverse wildlife remains poorly understood. Researchers use datasets, models, and analyses to define and infer the relationships between organisms and their environment, including impacts of resource exploitation. Such research underpins evidence-driven conservation and policy planning via recommendations to governmental organizations and non-governmental conservation groups. This study aims to create comprehensive conservation policy recommendations by utilizing large-scale and long-term datasets comprised from multiple sources, in varying formats, and with extensive metadata in order to reflect the complexity of the natural environment and more accurately understand the impact of anthropogenic pressures on wildlife populations. The datasets included in this study are time series data from wildlife markets on Bioko Island in Equatorial Guinea, georeferenced genome-wide single nucleotide polymorphism (SNP) panels from chimpanzees (Pan troglodytes) across Central Africa, and fine-scale climatic, habitat, and socioecological data for genetically distinct chimpanzee populations found in different habitats of varying anthropogenic pressures in Cameroon. The aims of this study are to: (1) Investigate the characteristics and drivers of the Malabo wildlife market's behavior over a 22-year period; (2) Quantify the impact of the recent COVID-19 pandemic on the supply of and demand for wildlife on Bioko; and (3) Determine if chimpanzee socioecological characteristics contribute to processes of chimpanzee speciation across Central Africa.