R. Alan Covey

Population genetic structure of traditional populations in the Peruvian Central Andes and implications for South American population history.

ABSTRACT Molecular-based characterizations of Andean peoples are traditionally conducted in the service of elucidating continent-level evolutionary processes in South America. Consequently, genetic variation among “western” Andean populations is often represented in relation to variation among “eastern” Amazon and Orinoco River Basin populations. This west-east contrast in patterns of population genetic variation is typically attributed to large-scale phenomena, such as dual founder colonization events or differing long-term microevolutionary histories. However, alternative explanations that consider the nature and causes of population genetic diversity within the Andean region remain underexplored. Here we examine population genetic diversity in the Peruvian Central Andes using data from the mtDNA first hypervariable region and Y-chromosome short tandem repeats among 17 newly sampled populations and 15 published samples. Using this geographically comprehensive data set, we first reassessed the currently accepted pattern of western versus eastern population genetic structure, which our results ultimately reject: mtDNA population diversities were lower, rather than higher, within Andean versus eastern populations, and only highland Y-chromosomes exhibited significantly higher within-population diversities compared with eastern groups. Multiple populations, including several highland samples, exhibited low genetic diversities for both genetic systems. Second, we explored whether the implementation of Inca state and Spanish colonial policies starting at about ad 1400 could have substantially restructured population genetic variation and consequently constitute a primary explanation for the extant pattern of population diversity in the Peruvian Central Andes. Our results suggest that Peruvian Central Andean population structure cannot be parsimoniously explained as the sole outcome of combined Inca and Spanish policies on the regions population demography: highland populations differed from coastal and lowland populations in mtDNA genetic structure only; highland groups also showed strong evidence of female-biased gene flow and/or effective sizes relative to other Peruvian ecozones. Taken together, these findings indicate that population genetic structure in the Peruvian Central Andes is considerably more complex than previously reported and that characterizations of and explanations for genetic variation may be best pursued within more localized regions and defined time periods.

The Economic Transformation of the Inca Heartland (Cuzco, Peru) in the Late Sixteenth Century

This paper uses documents generated by the 1594–1595 composiciones de tierras in Cuzco, Peru, to discuss the economic transformation of the former heartland of the Inca Empire and the impact of Spanish administrative policies implemented in the early 1570s. The diverse social and environmental landscapes of rural areas lying to the west of Cuzco provide a range of local case studies that reveal how settlement and tribute policies of the viceroy Francisco de Toledo failed to produce sustainable colonial towns of Christian Indians. Detailed records of indigenous land repartition in the area show gender- and status-based patterns of individual allocations, as well as ecological differences in landholding between communities. The local records indicate the continuing importance of Inca-era community identities and local leadership for maintaining possession of community lands. By contrast, documents related to the composiciones among private landowners reveal vast inequalities in land access, as well as the rapid growth in the demand for indigenous labor to produce important agrarian commodities. We argue that Spanish administrative policies accelerated the transformation of the means of production in rural Cuzco, creating peasants instead of Christian Indian subjects.

Archaeological Investigations at Yunkaray (Cuzco, Peru): Reconstructing the Rise and Fall of an Early Inca Rival (a.d. 1050–1450)

ABSTRACT In the highland Andes during the centuries leading to Inca imperial expansion (ca. a.d. 1400–1530s), the people of the Cuzco Basin established alliances and rivalries with diverse neighbors living across the Cuzco region. Among the most powerful of those groups was a polity centered at Yunkaray (occupied ca. a.d. 1050–1450) on the Maras Plain just northwest of the burgeoning city of Cuzco. Recent settlement survey and excavations in and around Yunkaray have identified the site as the principal settlement of the Ayarmaca group, which remained outside the sphere of Inca cultural influence despite its proximity to Cuzco. The distinctive nature of Yunkaray’s interaction with the Incas is examined here through household excavations, which indicate that the large village was occupied by a population presenting modest status distinctions and relying on locally derived sources of social identity.

The Huánuco Pampa acoustical field survey: an efficient, comparative archaeoacoustical method for studying sonic communication dynamics

The 2015 acoustical field survey on and around the central plaza platform (“ushnu”) at the Inca administrative complex of Huánuco Pampa advances understanding of Inca communication dynamics and innovates archaeoacoustical methodologies. We detail here a new archaeoacoustics method that cross-compares a sequence of human-performed sound sources along with a standard electronic acoustical test signal across survey points. This efficient and rigorous archaeological experiment produced extensible data and observations regarding Inca-designed site sonics and multi-directional communication dynamics. Our experiment design combines ecologically valid acoustical measurements with subjective researcher-observer data to chart sound transmission and reception of different classes of sound-producers, enabling the identification of environmental contingencies, and the estimation of site acoustical features. Calibrated, multiply repeated sonic test signals were measured from a strategically chosen set of geo-located and photo-documented source and receiver locations in absolute, relative, and subjective terms, simultaneously for each source-receiver pair. This method offers a systematic and comprehensive understanding of site-specific sonic dynamics via in-field observations and data recording, frequency-range comparison across test signals, attention to acoustical metrics and psychoacoustical precedents, and emphasis on practical repeatability for a range of archaeologically relevant sound sources. Our study posits the central platform at Huánuco Pampa as a strategic point for Inca elites to both observe and influence activities across the site, a finding extensible to other such platforms. The prominent architectural platform would serve as a tool for multi-directional communication, as well as to facilitate messaging about elite presence and imperial identity through the projection of sonic-visual displays. Beyond producing data about Huánuco Pampa and Inca architecture, our case-study implementation of this new method demonstrates an efficient and systematic approach to tracing the acoustical contingencies of architectural materials in archaeological contexts.

Andean exceptionalism and the new Inka scholarship

Grand theories of human social organisation have sometimes struggled to find a place for the Inka empire, which achieved an unprecedented degree of state power across the Andean region of western South America for a few generations in the late fifteenth and early sixteenth centuries AD. This is in part because the Inka realm looked so different from the ancient empires of Eurasia. The axis of Inka power ran north–south through some of the most diverse and difficult terrain on the planet, and Inka material culture and institutions lacked many of the Western hallmarks of civilisation. In Ancient society (1877), Lewis Henry Morgan relegated the Inkas to a status of ‘middle barbarism’ for possessing only Bronze Age metallurgy, placing a realm of perhaps 10 million inhabitants in the company of the Puebloan peoples of the American Southwest and the society that built Stonehenge. More than a century later, the sociologist Michael Mann (1986) offered the Inkas as an exception to his general model for wielding so much power without using writing, currency or low-cost forms of transportation.