Tales from the Supplementary Information: Ancestry Change in Chalcolithic–Early Bronze Age Britain Was Gradual with Varied Kinship Organization

Thomas J Booth,Selina Brace,Joanna Brück,Ian Barnes

doi:10.1017/s0959774321000019

Abstract

Large-scale archaeogenetic studies of people from prehistoric Europe tend to be broad in scope and difficult to resolve with local archaeologies. However, accompanying supplementary information often contains useful finer-scale information that is comprehensible without specific genetics expertise. Here, we show how undiscussed details provided in supplementary information of aDNA papers can provide crucial insight into patterns of ancestry change and genetic relatedness in the past by examining details relating to a >90 per cent shift in the genetic ancestry of populations who inhabited Chalcolithic and Early Bronze Age Britain (c. 2450–1600bc). While this outcome was certainly influenced by movements of communities carrying novel ancestries into Britain from continental Europe, it was unlikely to have been a simple, rapid process, potentially taking up to 16 generations, during which time there is evidence for the synchronous persistence of groups largely descended from the Neolithic populations. Insofar as genetic relationships can be assumed to have had social meaning, identification of genetic relatives in cemeteries suggests paternal relationships were important, but there is substantial variability in how genetic ties were referenced and little evidence for strict patrilocality or female exogamy.

Highlights

Over the last decade, a step-change in DNA sequencing technology has led to a collapse in the cost of generating genetic information
We show how these insights can be combined with other types of archaeological data to develop more reflexive narratives of the past by assessing data pertaining to the genetics of Chalcolithic–Early Bronze Age (C-EBA: c. 2450–1600 BC) Britain provided in the supplementary information of Olalde et al (2018)
We have shown just how much detailed information can be gleaned from the supplementary information associated with large-scale archaeogenetic studies without the application of additional specific expertise in molecular biology or bioinformatics

Summary

Introduction

A step-change in DNA sequencing technology has led to a collapse in the cost of generating genetic information. There is archaeogenetic evidence from other areas of prehistoric Europe that groups with distinctive ancestries coexisted in certain regions for hundreds and even thousands of years, including groups variably carrying steppe-related ancestry (Bollongino et al 2013; Furholt 2019; Furtwängler et al 2020; Lipson et al 2017; Mathieson et al 2018; Olalde et al 2019) In these regions of Europe, too, after apparent major genetic transformations of local ancestries, there are frequent later appearances of people carrying substantial ancestry from earlier periods, which is indicative of sampling bias in archaeogenetic analyses towards people with particular ancestries practising highly archaeologically visible funerary rites (Furholt 2019). Chronological phase model for C-EBA samples showing very little (0–5 per cent) or substantial (20–40 per cent) ancestry related to Neolithic populations of Britain suggesting population synchronicity. (Generated in OxCal 4.4 using the IntCal Curve: see Supplementary Table 3; Bronk Ramsey 2009; Reimer et al 2020.)

Conclusion

Findings

Midland Road London NW1 1AT