Late Archaic–Early Formative period microbotanical evidence for potato at Jiskairumoko in the Titicaca Basin of southern Peru

Abstract

The data presented in this paper provide direct microbotanical evidence concerning the early use of potato (Solanum tuberosum) within its botanical locus of origin in the high south-central Andes. The data derive from Jiskairumoko, an early village site in the western Titicaca Basin dating to the Late Archaic to Early Formative periods (∼3,400 cal y BC to 1,600 cal y BC). Because the site reflects the transition to sedentism and food production, these data may relate to potato domestication and early cultivation. Of 141 starch microremains recovered from 14 groundstone tools from Jiskairumoko, 50 are identified as consistent with cultivated or domesticated potato, based on reference to published materials and a study of wild and cultivated potato starch morphology. Along with macro- and microbotanical evidence for chenopod consumption and grinding tool data reflecting intensive use of this technology throughout site occupation, the microbotanical data reported here suggest the intensive exploitation, if not cultivation, of plant resources at Jiskairumoko. Elucidating the details of the trajectory of potato domestication is necessary for an overall understanding of the development of highland Andean agriculture, as this crop is central to the autochthonous agricultural suite. A paucity of direct botanical evidence, however, has hindered research efforts. The results of the modern and archaeological starch analyses presented here underscore the utility of this method in addressing questions related to the timing, mode, and context of potato origins.

The genetic prehistory of the Andean highlands 7,000 Years BP though European contact

“…Our model, utilizing a 1.25 x 10 -8 mutation rate, shows a correlation with archaeological evidence regarding the split between North and South groups occurring nearly 14,750 years ago (95% CI [14,225,15,775]), which agrees with the oldest known site in South America of Monte Verde in southern Chile (~14,000 years BP) (3). The date for the split between low and high-altitude populations was 20 inferred to 8,750 years (95% CI [8,200,9,250]), which is younger than previously reported by a study utilizing modern genomes alone (48). This date provides a terminus ante quem time frame for the origins of adaptations known in modern highland populations.…”

“…World centers for agriculture, which included starch-rich plants such as maize (~4000 years BP) (52) and the potato (~3400 Years BP) (8). Selection acting on the MGAM gene in the ancient Andeans may represent an adaptive response to greater reliance upon starchy domesticates.…”

“…5A, Table S4). MGAM is an intestinal enzyme associated with starch 30 digestion (35) and could possibly be linked to the intensification of tuber use and ultimately the transition to agriculture (8,36). The second strongest signal came from the gene DST, which encodes a cytoskeleton linker protein active in neural and muscle cells (37).…”

“…People likely entered the highlands shortly after their arrival on the continent (2,3), and while some have argued that humans lived permanently in the 5 Central Andean highlands by 12,000 BP (4), other research indicates that permanent occupation began between 9500-9000 BP (5)(6)(7). Regardless of when the peopling of high elevation environments began, selective pressure on the human genome was likely strong due to challenging environmental factors but also social processes such as the intensification of subsistence resources and residential sedentism (8), which in turn promoted the development of agricultural economies, 10 social inequality, and relatively high population densities across much of the highlands. European contact initiated an array of economic, social, and pathogenic changes (9, 10).…”

Starch granule evidence for the earliest potato use in North America

“…Intensive exploitation, perhaps of domesticated strains, took place between 3,400 and 1,600 cal B.P. in the western Titicaca Basin (11).…”