Isotopic and microbotanical insights into Iron Age agricultural reliance in the Central African rainforest

Dental calculus: A repository of bioinformation indicating diseases and human evolution

Dental calculus has long been considered as a vital contributing factor of periodontal diseases. Our review focuses on the role of dental calculus as a repository and discusses the bioinformation recently reported to be concealed in dental calculus from three perspectives: time-varying oral condition, systemic diseases, and anthropology at various times. Molecular information representing an individual's contemporary oral health status could be detected in dental calculus. Additionally, pathogenic factors of systemic diseases were found in dental calculus, including bacteria, viruses and toxic heavy metals. Thus, dental calculus has been proposed to play a role as biological data storage for detection of molecular markers of latent health concerns. Through the study of environmental debris in dental calculus, an overview of an individual's historical dietary habits and information about the environment, individual behaviors and social culture changes can be unveiled. This review summarizes a new role of dental calculus as a repository of bioinformation, with potential use in the prediction of oral diseases, systemic diseases, and even anthropology.

Analysis of Early Iron Age (2500 BP) and modern period (150 BP) starch grains in Western Central Africa

Starch grain analysis carried out on 23 ceramic sherds from 6 refuse pits from the site of Nachtigal in central Cameroon is shedding light on a longstanding debate regarding ancient diets in Central Africa during the Iron Age (IA, 2500 years BP) but also more recently during the Modern Period (ca. 150 BP). The results indicate a varied, but balanced diet, consisting of cereals, legumes, oil-rich seeds, and tubers; the latter being very rarely documented in the region. Moreover, we underscore the presence of taxa still consumed today, or in recent times. Rescue archaeology, and the application of specialized methodologies, are critical to better nuancing past dietary practices in this region.

Phylogeographic analysis of the Bantu language expansion supports a rainforest route

Southern Africa has been shaped by the large-scale expansion of Bantu populations fueled by agriculture: Currently, 240 million people speak one of the more than 500 Bantu languages. However, the timing and geographic routes undergone by the Bantu populations remain largely unknown. We use cutting-edge phylogeographic techniques to show that Bantu populations migrated through the Central African tropical rainforest around 4,400 y ago. This adds to the growing evidence that agricultural expansions can successfully overcome ecological challenges as they unfold.

The Bantu expansion transformed the linguistic, economic, and cultural composition of sub-Saharan Africa. However, the exact dates and routes taken by the ancestors of the speakers of the more than 500 current Bantu languages remain uncertain. Here, we use the recently developed “break-away” geographical diffusion model, specially designed for modeling migrations, with “augmented” geographic information, to reconstruct the Bantu language family expansion. This Bayesian phylogeographic approach with augmented geographical data provides a powerful way of linking linguistic, archaeological, and genetic data to test hypotheses about large language family expansions. We compare four hypotheses: an early major split north of the rainforest; a migration through the Sangha River Interval corridor around 2,500 BP; a coastal migration around 4,000 BP; and a migration through the rainforest before the corridor opening, at 4,000 BP. Our results produce a topology and timeline for the Bantu language family, which supports the hypothesis of an expansion through Central African tropical forests at 4,420 BP (4,040 to 5,000 95% highest posterior density interval), well before the Sangha River Interval was open.

Stable Isotopic Evidence for Human and Animal Diets From the Late Neolithic to the Ming Dynasty in the Middle-Lower Reaches of the Hulu River Valley, NW China

The study of human and animal paleodiets, representing the unique subsistence strategies and human-environment interactions adopted over evolutionary time, has attracted intensive research attention. Historically, the western Loess Plateau (WLP) served as a key area for the evolution of human-land relationship. The human subsistence patterns in the WLP changed significantly from prehistoric to historical periods based on archaeobotanical data. However, the trajectory and influencing factors of ancient human and animal diets in the WLP remain unclear, mainly due to the lack of isotopic data in the upper reaches of the Wei River. In this paper, we reported 172 human and animal isotope samples (C and N) and 23 radiocarbon dates from three sites in the middle-lower reaches of the Hulu River Valley (HRV). At least three periods of dietary patterns for humans were observed in the WLP from the late Neolithic to Ming Dynasty. During 5300–4000 Before Present (BP), humans and domesticated animals such as pigs and dogs consumed a greater proportion of millets and millet byproducts. Between 3000 and 2200 BP, the diets of pigs and dogs remained largely comprised of C4 foods, while humans consumed both C3 and C4 foods, which contradicted the evidence of an overwhelming proportion of wheat and barley (C3 crops) from the contemporaneous cultural sediment. The contradictions between plant remains and human diets are probably related to geopolitical factors. Between 1000–500 BP, human diets were more diverse and heterogeneous in this region. Combined with environmental and archaeological evidence, the changes in diets and subsistence strategies over the three periods can be attributed to the comprehensive influence of regional cultural development, geopolitics and technological innovation. This paper not only reveals the trajectory and influencing factors of ancient human and animal diets in the middle-lower HRV, but also explores how subsistence strategies, particularly in terms of dietary structure, will change in the context of cultural exchange and diffusion, and emphasizes the important influence of geopolitical interactions in the WLP.

Human behaviour and climate-linked fluctuations in the rainforests of West-Central Africa

Africa, the cradle of human evolution, has one of the largest and most diverse rainforests in the world. The African rainforests contain evidence of human occupation as well as fluctuating climate during the Pleistocene; such evidence offers archaeologists and palaeoecologists the opportunity to understand how climatic fluctuations have influenced human behaviour. However, compared to the rainforests environments in Asia and South America, the human ecological history of those in West-Central Africa is poorly understood. This is because of comparatively fewer scientific programmes which synergize palaeoecological and archaeological data and thus could enhance the knowledge and allow for an evaluation of the impact of climatic fluctuations on human behaviour in the rainforests of West-Central Africa during the Pleistocene and Holocene periods. The goals of this paper are twofold, namely: (i) to provide a synthesis of the past climatic variability in the rainforests of West-Central Africa, and (ii) to demonstrate the influence of such variability on human behaviour during the Pleistocene to Holocene periods. It is hoped that this paper will stimulate Africanists to adopt an inclusive scientific anthropological and palaeoecological approach in understanding human-climate interactions in the West-Central African rainforests. This article is part of the theme issue 'Tropical forests in the deep human past'.