Pre-Clovis occupation of the Americas identified by human fecal biomarkers in coprolites from Paisley Caves, Oregon

Lisa-Marie Shillito,John C Blong,Ian D Bull,Helen L Whelton,Thomas J Connolly,Dennis L Jenkins

doi:10.1126/sciadv.aba6404

Lisa-Marie Shillito, John C Blong + Show 4 more

Open Access

https://doi.org/10.1126/sciadv.aba6404

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Abstract

When and how people first settled in the Americas is an ongoing area of research and debate. The earliest sites typically only contain lithic artifacts that cannot be directly dated. The lack of human skeletal remains in these early contexts means that alternative sources of evidence are needed. Coprolites, and the DNA contained within them, are one such source, but unresolved issues concerning ancient DNA taphonomy and potential for contamination make this approach problematic. Here, we use fecal lipid biomarkers to demonstrate unequivocally that three coprolites dated to pre-Clovis are human, raise questions over the reliance on DNA methods, and present a new radiocarbon date on basketry further supporting pre-Clovis human occupation.

Highlights

But not entirely, accepted by the archaeological community that people first settled the Americas before Clovis [1,2,3], which was seen as the earliest technological tradition on the continent for most of the 20th century, dating to 11,500 radiocarbon years before the present (14C yr B.P.) many questions still remain over who the earliest settlers were, when they arrived, and what route they took
This is a crucial case study as it remains the only site where a pre-Clovis Western Stemmed Tradition (WST) assemblage has been found in direct association with well-preserved organic cultural material, enabling us to better understand these early settlers and their way of life
The results presented by Jenkins et al [3] showed that, in one sample, the dates obtained on macrofossils and water-soluble extracts from a Camelidae coprolite were 12,125 ± 30 14C yr B.P. for the macrofossil and 11,315 ± 25 14C yr B.P. for the water-s oluble extract

Summary

INTRODUCTION

But not entirely, accepted by the archaeological community that people first settled the Americas before Clovis [1,2,3], which was seen as the earliest technological tradition on the continent for most of the 20th century, dating to 11,500 radiocarbon years before the present (14C yr B.P.) many questions still remain over who the earliest settlers were, when they arrived, and what route they took. The Paisley Caves contain additional evidence for pre-Clovis occupation in the form of coprolites dating to 12,400 14C yr B.P. identified as human on the basis that they contain human DNA [3, 5] This is a crucial case study as it remains the only site where a pre-Clovis WST assemblage has been found in direct association with well-preserved organic cultural material, enabling us to better understand these early settlers and their way of life. Three coprolites identified as human were dated this way but showed an agreement between the macroflora and solute dates While this strongly supports the interpretation that humans occupied the site in pre-Clovis times, the ambiguity remains that DNA is potentially mobile in sediments [9, 10], and linking a DNA signal with a specific radiocarbon date is problematic. We present compelling new, fecal biomarker– based evidence that reveals, without any ambiguity from the interpretation, that pre-Clovis coprolites from the Paisley Caves complex are human

RESULTS

DISCUSSION

MATERIALS AND METHODS