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Humans settled the Caribbean about 6,000 years ago, and ceramic use and intensified agriculture mark a shift from the Archaic to the Ceramic Age at around 2,500 years ago 1 – 3 . Here we report genome-wide data from 174 ancient individuals from The Bahamas, Haiti and the Dominican Republic (collectively, Hispaniola), Puerto Rico, Curaçao and Venezuela, which we co-analysed with 89 previously published ancient individuals. Stone-tool-using Caribbean people, who first entered the Caribbean during the Archaic Age, derive from a deeply divergent population that is closest to Central and northern South American individuals; contrary to previous work 4 , we find no support for ancestry contributed by a population related to North American individuals. Archaic-related lineages were >98% replaced by a genetically homogeneous ceramic-using population related to speakers of languages in the Arawak family from northeast South America; these people moved through the Lesser Antilles and into the Greater Antilles at least 1,700 years ago, introducing ancestry that is still present. Ancient Caribbean people avoided close kin unions despite limited mate pools that reflect small effective population sizes, which we estimate to be a minimum of 500–1,500 and a maximum of 1,530–8,150 individuals on the combined islands of Puerto Rico and Hispaniola in the dozens of generations before the individuals who we analysed lived. Census sizes are unlikely to be more than tenfold larger than effective population sizes, so previous pan-Caribbean estimates of hundreds of thousands of people are too large 5 , 6 . Confirming a small and interconnected Ceramic Age population 7 , we detect 19 pairs of cross-island cousins, close relatives buried around 75 km apart in Hispaniola and low genetic differentiation across islands. Genetic continuity across transitions in pottery styles reveals that cultural changes during the Ceramic Age were not driven by migration of genetically differentiated groups from the mainland, but instead reflected interactions within an interconnected Caribbean world 1 , 8 . Ancient DNA reveals genetic differences between stone-tool users and people associated with ceramic technology in the Caribbean and provides substantially lower estimates of population sizes in the region before European contact.

The origin and spread of domestic animals across the globe also affected the underlying genetic composition of human populations. In Africa, however, it has been difficult to identify the impact of interactions among migrating food producers and local hunter-gatherers. Prendergast et al. wanted to discern the timing and movement of husbandry and pastoralism and its effects on foraging communities in Africa. They sequenced 41 ancient eastern African human genomes from individuals that lived approximately 100 to 4000 years ago. Surprisingly, relatively little genetic mixture occurred at the same time as the spread of pastoralism. Science , this issue p. eaaw6275 Ancient Africans’ genomes document diffusion and admixture during the spread of food production How food production first entered eastern Africa ~5000 years ago and the extent to which people moved with livestock is unclear. We present genome-wide data from 41 individuals associated with Later Stone Age, Pastoral Neolithic (PN), and Iron Age contexts in what are now Kenya and Tanzania to examine the genetic impacts of the spreads of herding and farming. Our results support a multiphase model in which admixture between northeastern African–related peoples and eastern African foragers formed multiple pastoralist groups, including a genetically homogeneous PN cluster. Additional admixture with northeastern and western African–related groups occurred by the Iron Age. These findings support several movements of food producers while rejecting models of minimal admixture with foragers and of genetic differentiation between makers of distinct PN artifacts.

Relatively little is known about Nubia’s genetic landscape prior to the influence of the Islamic migrations that began in the late 1st millennium CE. Here, we increase the number of ancient individuals with genome-level data from the Nile Valley from three to 69, reporting data for 66 individuals from two cemeteries at the Christian Period (~650–1000 CE) site of Kulubnarti, where multiple lines of evidence suggest social stratification. The Kulubnarti Nubians had ~43% Nilotic-related ancestry (individual variation between ~36–54%) with the remaining ancestry consistent with being  introduced through Egypt and ultimately deriving from an ancestry pool like that found in the Bronze and Iron Age Levant. The Kulubnarti gene pool – shaped over a millennium – harbors disproportionately female-associated West Eurasian-related ancestry. Genetic similarity among individuals from the two cemeteries supports a hypothesis of social division without genetic distinction. Seven pairs of inter-cemetery relatives suggest fluidity between cemetery groups. Present-day Nubians are not directly descended from the Kulubnarti Nubians, attesting to additional genetic input since the Christian Period. Little is known about the genetic landscape of people living in the Nile region prior to the Islamic migrations of the late 1st millennium CE. Here, the authors report genome-wide data for 66 ancient individuals to investigate the genetic ancestry of a Christian Period group from Kulubnarti.

Background The Deepwater Horizon disaster was the largest marine oil spill in history, and total vertical exposure of oil to the water column suggests it could impact an enormous diversity of ecosystems. The most vulnerable organisms are those encountering these pollutants during their early life stages. Water-soluble components of crude oil and specific polycyclic aromatic hydrocarbons have been shown to cause defects in cardiovascular and craniofacial development in a variety of teleost species, but the developmental origins of these defects have yet to be determined. We have adopted zebrafish, Danio rerio , as a model to test whether water accumulated fractions (WAF) of the Deepwater Horizon oil could impact specific embryonic developmental processes. While not a native species to the Gulf waters, the developmental biology of zebrafish has been well characterized and makes it a powerful model system to reveal the cellular and molecular mechanisms behind Macondo crude toxicity. Results WAF of Macondo crude oil sampled during the oil spill was used to treat zebrafish throughout embryonic and larval development. Our results indicate that the Macondo crude oil causes a variety of significant defects in zebrafish embryogenesis, but these defects have specific developmental origins. WAF treatments caused defects in craniofacial development and circulatory function similar to previous reports, but we extend these results to show they are likely derived from an earlier defect in neural crest cell development. Moreover, we demonstrate that exposure to WAFs causes a variety of novel deformations in specific developmental processes, including programmed cell death, locomotor behavior, sensory and motor axon pathfinding, somitogenesis and muscle patterning. Interestingly, the severity of cell death and muscle phenotypes decreased over several months of repeated analysis, which was correlated with a rapid drop-off in the aromatic and alkane hydrocarbon components of the oil. Conclusions Whether these teratogenic effects are unique to the oil from the Deepwater Horizon oil spill or generalizable for most crude oil types remains to be determined. This work establishes a model for further investigation into the molecular mechanisms behind crude oil mediated deformations. In addition, due to the high conservation of genetic and cellular processes between zebrafish and other vertebrates, our work also provides a platform for more focused assessment of the impact that the Deepwater Horizon oil spill has had on the early life stages of native fish species in the Gulf of Mexico and the Atlantic Ocean.

Phenology is a key aspect of plant success. Recent research has demonstrated that herbarium specimens can provide important information on plant phenology. Massive digitization efforts have the potential to greatly expand herbarium-based phenological research, but also pose a serious challenge regarding efficient data collection. Here, we introduce CrowdCurio, a crowdsourcing tool for the collection of phenological data from herbarium specimens. We test its utility by having workers collect phenological data (number of flower buds, open flowers and fruits) from specimens of two common New England (USA) species: Chelidonium majus and Vaccinium angustifolium. We assess the reliability of using non-expert workers (i.e. Amazon Mechanical Turk) against expert workers. We also use these data to estimate the phenological sensitivity to temperature for both species across multiple phenophases. We found no difference in the data quality of nonexperts and experts. Nonexperts, however, were a more efficient way of collecting more data at lower cost. We also found that phenological sensitivity varied across both species and phenophases. Our study demonstrates the utility of CrowdCurio as a crowdsourcing tool for the collection of phenological data from herbarium specimens. Furthermore, our results highlight the insight gained from collecting large amounts of phenological data to estimate multiple phenophases.

Steppe-pastoralist-related ancestry reached Central Europe by at least 2500 bc , whereas Iranian farmer-related ancestry was present in Aegean Europe by at least 1900 bc . However, the spread of these ancestries into the western Mediterranean, where they have contributed to many populations that live today, remains poorly understood. Here, we generated genome-wide ancient-DNA data from the Balearic Islands, Sicily and Sardinia, increasing the number of individuals with reported data from 5 to 66. The oldest individual from the Balearic Islands (~2400 bc ) carried ancestry from steppe pastoralists that probably derived from west-to-east migration from Iberia, although two later Balearic individuals had less ancestry from steppe pastoralists. In Sicily, steppe pastoralist ancestry arrived by ~2200 bc , in part from Iberia; Iranian-related ancestry arrived by the mid-second millennium bc, contemporary to its previously documented spread to the Aegean; and there was large-scale population replacement after the Bronze Age. In Sardinia, nearly all ancestry derived from the island’s early farmers until the first millennium bc , with the exception of an outlier from the third millennium bc , who had primarily North African ancestry and who—along with an approximately contemporary Iberian—documents widespread Africa-to-Europe gene flow in the Chalcolithic. Major immigration into Sardinia began in the first millennium bc and, at present, no more than 56–62% of Sardinian ancestry is from its first farmers. This value is lower than previous estimates, highlighting that Sardinia, similar to every other region in Europe, has been a stage for major movement and mixtures of people. The history of human populations in the islands of the central and western Mediterranean is poorly understood. Here, the authors generate ancient-DNA data from the Balearic Islands, Sicily and Sardinia, and estimate the level and timing of steppe pastoralist, Iranian and North African ancestries in these populations.

The Central Siberian Plateau was the last geographic area in Eurasia to become habitable by modern humans after the Last Glacial Maximum (LGM). Through a comprehensive dataset of mitochondrial DNA (mtDNA) genomes retained in the remnats of earlier (“Old”) Siberians, primarily the Ket, Tofalar, and Todzhi, we explored genetic links between the Yenisei-Sayan region and Northeast Eurasia (best represented by the Yukaghir) over the last 10,000 years. We generated 218 new complete mtDNA sequences and placed them into compound phylogenies with 7 newly obtained and 70 published ancient mitochondrial genomes. We have considerably extended the mtDNA sequence diversity (at the entire mtDNA genome level) of autochthonous Siberians, which remain poorly sampled, and these new data may have a broad impact on the study of human migration. We compared present-day mtDNA diversity in these groups with complete mitochondrial genomes from ancient samples from the region and placed the samples into combined genealogical trees. The resulting components were used to clarify the origins and expansion history of mtDNA lineages that evolved in the refugia of south-central Siberia and beyond, as well as multiple phases of connection between this region and distant parts of Eurasia.

Situated at over 5,000 meters above sea level in the Himalayan Mountains, Roopkund Lake is home to the scattered skeletal remains of several hundred individuals of unknown origin. We report genome-wide ancient DNA for 38 skeletons from Roopkund Lake, and find that they cluster into three distinct groups. A group of 23 individuals have ancestry that falls within the range of variation of present-day South Asians. A further 14 have ancestry typical of the eastern Mediterranean. We also identify one individual with Southeast Asian-related ancestry. Radiocarbon dating indicates that these remains were not deposited simultaneously. Instead, all of the individuals with South Asian-related ancestry date to ~800 CE (but with evidence of being deposited in more than one event), while all other individuals date to ~1800 CE. These differences are also reflected in stable isotope measurements, which reveal a distinct dietary profile for the two main groups. Remains of several hundred humans are scattered around Roopkund Lake, situated over 5,000 meters above sea level in the Himalayan Mountains. Here the authors analyze genome-wide data from 38 skeletons and find 3 clusters with different ancestries and dates, showing the people were desposited in multiple catastrophic events.

In 1867, the State Cabinet, an extensive collection of specimens representing the natural history of Massachusetts, was transferred from the State House in Boston, MA, to the new Massachusetts Agricultural College in Amherst (now the University of Massachusetts). The botanical portion of the State Cabinet has remained intact, and relatively unknown, for the last 148 years at the University of Massachusetts Herbarium. Over the course of two years we completely curated the collection, performed restoration work, and researched the history of the collectors associated with the State Cabinet with a goal of making the collection available online. We were able to assign collectors and collection dates to 84% of the collections that were missing this information. The primary collectors, Charles Jarvis (1800–1826), Edward Jarvis (1803–1884), and Henry Little (1802–1826), were a group of Harvard-educated physicians whose botanical interests were probably inspired by the instruction they received in natural history at Harvard University. The State Cabinet consists of 1509 sheets and includes 905 taxa, an increase from the original, sometimes incomplete identifications based on the Linnaean System. Most of the plants in the collection are from the greater Boston, MA, area, particularly Concord, MA. The Jarvis collection includes the earliest recorded specimens from Concord, MA, and the Little collection includes a few early specimens from the White Mountains as well as specimens cited in the second edition of Bigelow’s Florula Bostoniensis published in 1824. The State Cabinet provides a window into early 19th century botany in New England.

Present-day people from England and Wales have more ancestry derived from early European farmers (EEF) than did people of the Early Bronze Age 1 . To understand this, here we generated genome-wide data from 793 individuals, increasing data from the Middle to the Late Bronze Age and Iron Age in Britain by 12-fold, and western and central Europe by 3.5-fold. Between 1000 and 875 bc , EEF ancestry increased in southern Britain (England and Wales) but not northern Britain (Scotland) due to incorporation of migrants who arrived at this time and over previous centuries, and who were genetically most similar to ancient individuals from France. These migrants contributed about half the ancestry of people of England and Wales from the Iron Age, thereby creating a plausible vector for the spread of early Celtic languages into Britain. These patterns are part of a broader trend of EEF ancestry becoming more similar across central and western Europe in the Middle to the Late Bronze Age, coincident with archaeological evidence of intensified cultural exchange 2 – 6 . There was comparatively less gene flow from continental Europe during the Iron Age, and the independent genetic trajectory in Britain is also reflected in the rise of the allele conferring lactase persistence to approximately 50% by this time compared to approximately 7% in central Europe where it rose rapidly in frequency only a millennium later. This suggests that dairy products were used in qualitatively different ways in Britain and in central Europe over this period. Genome-wide ancient DNA data from individuals from the Middle Bronze Age to Iron Age documents large-scale movement of people from the European continent between 1300 and 800 bc  that was probably responsible for spreading early Celtic languages to Britain.