The brains of modern humans differ from those of great apes in size, shape,
and cortical organization, notably in frontal lobe areas involved in complex
cognitive tasks, such as social cognition, tool use, and language. When these
differences arose during human evolution is a question of ongoing debate. Here, we
show that the brains of early Homo from Africa and
Western Asia (Dmanisi) retained a primitive, great ape–like organization of the
frontal lobe. By contrast, African Homo younger than
1.5 million years ago, as well as all Southeast Asian Homo
erectus, exhibited a more derived, humanlike brain organization.
Frontal lobe reorganization, once considered a hallmark of earliest
Homo in Africa, thus evolved comparatively late, and
long after Homo first dispersed from Africa.
SignificanceThe cavity system of the inner ear—the so-called bony labyrinth—houses the senses of balance and hearing. This structure is embedded in dense petrous bone, fully formed by birth and generally well preserved in human skeletal remains, thus providing a rich source of morphological information about past populations. Here we show that labyrinthine morphology tracks genetic distances and geography in an isolation-by-distance model with dispersal from Africa. Because petrous bones have become prime targets of ancient DNA recovery, we propose that all destructive studies first acquire high-resolution 3D computed-tomography data prior to any invasive sampling. Such data will constitute an important archive of morphological variation in past and present populations, and will permit individual-based genotype–phenotype comparisons.
Previous research indicates that human genetic diversity in Wallacea—islands in present-day Eastern Indonesia and Timor-Leste that were never part of the Sunda or Sahul continental shelves—has been shaped by complex interactions between migrating Austronesian farmers and indigenous hunter–gatherer communities. Yet, inferences based on present-day groups proved insufficient to disentangle this region’s demographic movements and admixture timings. Here, we investigate the spatio-temporal patterns of variation in Wallacea based on genome-wide data from 16 ancient individuals (2600–250 years BP) from the North Moluccas, Sulawesi and East Nusa Tenggara. While ancestry in the northern islands primarily reflects contact between Austronesian- and Papuan-related groups, ancestry in the southern islands reveals additional contributions from Mainland Southeast Asia that seem to predate the arrival of Austronesians. Admixture time estimates further support multiple and/or continuous admixture involving Papuan- and Asian-related groups throughout Wallacea. Our results clarify previously debated times of admixture and suggest that the Neolithic dispersals into Island Southeast Asia are associated with the spread of multiple genetic ancestries.
This paper focus on chewing betel quid habit that dominantly happen in the Asia to Pacific region. Betel quid leaves traces of reddish-brown colour on the teeth. It was identified that dental stain was very common on teeth of prehistoric skeletal remains, for example in Thailand and Vietnam. Several studies have shown that chewing betel nut can cause diseases in the teeth and oral cavity. The purpose of this study is to describe the relationship between betel nut chewing and the emergence of tooth pathology in teeth from the prehistoric population from Lewoleba and Liang Bua. Ten individuals were observed using the macroscopic method. The results showed that consumption of betel nut (based on dental stains) was followed by attrition, periodontitis and even antemortem tooth loss.
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