South-to-north migration preceded the advent of intensive farming in the Maya region

This is the final version. Available on open access from Nature Research via the DOI in this recordData availability: The aligned sequences have been deposited in the European Nucleotide Archive database under accession code PRJEB49391. The processed genotype data used in analysis are available online on the Nature Communications website as Supplementary Data 9.The genetic prehistory of human populations in Central America is largely unexplored leaving an important gap in our knowledge of the global expansion of humans. We report genome-wide ancient DNA data for a transect of twenty individuals from two Belize rock-shelters dating between 9,600-3,700 calibrated radiocarbon years before present (cal. BP). The oldest individuals (9,600-7,300 cal. BP) descend from an Early Holocene Native American lineage with only distant relatedness to present-day Mesoamericans, including Mayan-speaking populations. After ~5,600 cal. BP a previously unknown human dispersal from the south made a major demographic impact on the region, contributing more than 50% of the ancestry of all later individuals. This new ancestry derived from a source related to present-day Chibchan speakers living from Costa Rica to Colombia. Its arrival corresponds to the first clear evidence for forest clearing and maize horticulture in what later became the Maya region.Alphawood FoundationNational Science Foundation (NSF)National Institutes of Health (NIH)John Templeton FoundationPaul G. Allen Family Foundatio

Prevalence of anaemia in older persons: systematic review

<p>Abstract</p> <p>Background</p> <p>Ageing populations will impact on healthcare provision, especially since extra years are not necessarily spent in good health. It is important to identify and understand the significance of common medical problems in older people. Anaemia may be one such problem. We report on the prevalence of anaemia in cohorts of elderly people in the general population. The presence of anaemia is associated with a worse prognosis for both morbidity and mortality.</p> <p>Methods</p> <p>Electronic searching and reference lists of published reports were used to identify studies that reported on prevalence of anaemia in cohorts of at least 100 individuals predominantly aged 65 years and over living in developed countries, together with criteria used to define anaemia. Studies of anaemia prevalence in specific disease groups or published before 1980 were excluded. Prevalence data for the entire cohort, for men and women separately and for different age bands were extracted.</p> <p>Results</p> <p>Forty-five studies contributed data. Thirty-four studies (n = 85,409) used WHO criteria to define anaemia. The weighted mean prevalence was 17% (3–50%) overall, and 12% (3–25%) in studies based in the community (27, n = 69,975), 47% (31–50%) in nursing homes (3, n = 1481), and 40% (40–72%) in hospital admissions (4, n = 13,953). Anaemia prevalence increased with age, was slightly higher in men than women, and was higher in black people than white. Most individuals classified as anaemic using WHO criteria were only mildly anaemic.</p> <p>Conclusion</p> <p>Anaemia, as defined by WHO criteria, is common in older people living in the community and particularly common in nursing home residents and hospital admissions. Predicted demographic changes underline the need to understand more about anaemia in older people.</p

The formation of human populations in South and Central Asia

By sequencing 523 ancient humans, we show that the primary source of ancestry in modern South Asians is a prehistoric genetic gradient between people related to early hunter-gatherers of Iran and Southeast Asia. After the Indus Valley Civilization’s decline, its people mixed with individuals in the southeast to form one of the two main ancestral populations of South Asia, whose direct descendants live in southern India. Simultaneously, they mixed with descendants of Steppe pastoralists who, starting around 4000 years ago, spread via Central Asia to form the other main ancestral population. The Steppe ancestry in South Asia has the same profile as that in Bronze Age Eastern Europe, tracking a movement of people that affected both regions and that likely spread the distinctive features shared between Indo-Iranian and Balto-Slavic languages

Is it agriculture yet? Intensified maize-use at 1000cal BC in the Soconusco and Mesoamerica

The development of food production in Mesoamerica was a complex and protracted process. We argue that while maize had been cultivated for many millennia, this cereal grain assumed a markedly more important role in the political economy of the Soconusco (and elsewhere in Mexico, Guatemala and Belize) only after 1000. cal BC. Macrobotanical data from the long-occupied village of Cuauhtémoc document low-level maize production from 1900 to 1400. cal BC with a significant increase during the final centuries of the site's occupation after 1000. cal BC. Botanical evidence of increased maize consumption at this time occurred with evidence for changing groundstone use, intensified exploitation of dog and deer as well as iconography linking maize with rulership. This was also when monumental architecture was first built to mark a regional hierarchy of political centers. Changes evident in the Soconusco at 1000. cal BC parallel transformations in both highland and lowland regions of Mesoamerica when ceramic-using villagers expanded into new environments, farther away from the permanent water sources favored by Late Archaic and Early Formative peoples. We interpret the changes evident at 1000. cal BC in terms of both proximate historical factors as well as ultimate adaptive causes to produce a fuller understanding of changing Mesoamerican food production practices

Is it agriculture yet? Intensified maize-use at 1000cal BC in the Soconusco and Mesoamerica

The development of food production in Mesoamerica was a complex and protracted process. We argue that while maize had been cultivated for many millennia, this cereal grain assumed a markedly more important role in the political economy of the Soconusco (and elsewhere in Mexico, Guatemala and Belize) only after 1000. cal BC. Macrobotanical data from the long-occupied village of Cuauhtémoc document low-level maize production from 1900 to 1400. cal BC with a significant increase during the final centuries of the site's occupation after 1000. cal BC. Botanical evidence of increased maize consumption at this time occurred with evidence for changing groundstone use, intensified exploitation of dog and deer as well as iconography linking maize with rulership. This was also when monumental architecture was first built to mark a regional hierarchy of political centers. Changes evident in the Soconusco at 1000. cal BC parallel transformations in both highland and lowland regions of Mesoamerica when ceramic-using villagers expanded into new environments, farther away from the permanent water sources favored by Late Archaic and Early Formative peoples. We interpret the changes evident at 1000. cal BC in terms of both proximate historical factors as well as ultimate adaptive causes to produce a fuller understanding of changing Mesoamerican food production practices

War and food production at the postclassic Maya city of Mayapan

Serafin, S ORCiD: 0000-0003-1665-8985In this chapter, we explore the nature of food production systems at Mayapán within the context of increasing warfare and militarism during the Postclassic period (Serafin et al. 2014)