The early lives of the islanders: Stable isotope analysis of incremental dentine collagen from the prehispanic period of the Canary Islands.

OBJECTIVES: This study presents isotopic information for incremental dentine collagen and bone bulk collagen from individuals from the Canary Islands (Tenerife and Gran Canaria) to explore dietary differences during childhood life. MATERIALS AND METHODS: Eight individuals have been studied, which comprises 122 δ15 N and δ13 C incremental dentine measurements and eight bulk bone collagen analyses. A baseline of potentially consumed food sources has been developed for comparative purposes. A food reconstruction using isotopic transferred signals (FRUITS) model of probable contributions of each food source towards the diet of each individual has been developed. All samples but one belongs to the later period of indigenous occupation of the archipelago. RESULTS: The dentine collagen data are presented in correlated δ13 C and δ15 N plots per individual, showing the isotopic changes throughout time. δ15 N values for each individual tend to be variable whereas δ13 C data are generally more stable with a range of +9.1 to +14‰ for δ15 N and -17.4 to -20.8‰ for δ13 C. CONCLUSION: The isotopic analysis allows for the reconstruction of eight dietary profiles, which allow us to estimate the different dietary protein sources. The FRUITS model shows different percentages of the primary food sources for each individual. Where both δ13 C and δ15 N are elevated, this could be indicative of a higher marine contribution to the diet. There appear to be two main dietary profiles identifiable in the dataset and these may be related to changes in status or place of residence. Short-term variations in δ13 C and δ15 N and opposing co-variance of isotopic values can be indicative of nutritional stress, although metabolic changes during growth are also considered.

The genomic history of the indigenous people of the Canary Islands.

The indigenous population of the Canary Islands, which colonized the archipelago around the 3rd century CE, provides both a window into the past of North Africa and a unique model to explore the effects of insularity. We generate genome-wide data from 40 individuals from the seven islands, dated between the 3rd-16rd centuries CE. Along with components already present in Moroccan Neolithic populations, the Canarian natives show signatures related to Bronze Age expansions in Eurasia and trans-Saharan migrations. The lack of gene flow between islands and constant or decreasing effective population sizes suggest that populations were isolated. While some island populations maintained relatively high genetic diversity, with the only detected bottleneck coinciding with the colonization time, other islands with fewer natural resources show the effects of insularity and isolation. Finally, consistent genetic differentiation between eastern and western islands points to a more complex colonization process than previously thought.

Dietary changes across time: Studying the indigenous period of La Gomera using δ13 C and δ15 N stable isotope analysis and radiocarbon dating.

OBJECTIVES: This article presents new radiocarbon and isotopic data to provide further information about the diet of the indigenous population of La Gomera and its possible changes across time. MATERIALS AND METHODS: δ13 C and δ15 N of 53 human and 19 faunal samples from different sites on the island have been obtained and analyzed. Of these, 52 have been radiocarbon dated to provide insight on chronological changes. RESULTS: Human dates range from the 3rd to 15th centuries AD, while faunal dates range from the 1st to 17th centuries AD. Stable carbon and nitrogen values are significantly different between the human and goat samples and have also a trophic increase of 3.4‰. Although male and female δ15 N data are not significantly different. Both δ13 C and δ15 N values of both human and animal samples tend to discretely decrease over time. DISCUSSION: Radiocarbon dates from humans correlate with other dates obtained in the rest of the archipelago. Animal radiocarbon dates generally coincide except for one date, which requires further study. Isotopic δ15 N data suggest a mix of marine and terrestrial protein consumption in humans, the latter being more abundant given the seasonality of the first. δ13 C data also suggest a possible mixed diet in humans, with a predominance of C3 plants, like Hordeum vulgare, the only grain found in archaeological sites so far. Variations of both δ13 C and δ15 N over time suggest a slight modification on the diet, which could be related to environmental changes.