Ritual complexity in a past community revealed by ancient DNA analysis of pre-colonial terracotta items from Northern Ghana

Abstract

19The pre-colonial 6 th 14 th century terracotta forms of Koma Land, Northern Ghana, contain 20 cavities which may have been intended to hold liquids. These have been linked to traditional 21African libation, but the specific nature of their contents is unclear. We used generic 22 polymerase chain reactions that would amplify DNA from a range of plant and fungal 23 species in order to identify remains of libations applied to fourteen terracotta items. We 24 anticipated difficulties in distinguishing genuine ancient DNA sequences from those resulting 25 from contaminating material, and therefore also carried out a series of control experiments 26 to assess the extent to which the samples had become contaminated with exogenous DNA 27 during burial, excavation and downstream analysis. Taking account of the results of the 28 control experiments, as well as the difficulties in assigning matches between ancient DNA 29 sequences and database entries, we provide evidence for the use of three different types of 30 plant plantain/banana, pine and grasses in libations associated with the terracotta items. 31We also identified DNA from Coniochaeta yeast within the mouth cavity of one figurine, 32 suggesting that this structure was burnt prior to deposition. 33 34

Asian Crop Dispersal in Africa and Late Holocene Human Adaptation to Tropical Environments

“…Although the Nkang phytoliths are accepted as Musa, the early date for banana at Nkang is not accepted by all, due to the low numbers of phytoliths (n = 25) (Perrier et al 2011), the lack of banana phytoliths in more recent sediments and the possibility of stratigraphic mixing (Neumann and Hildebrand 2009;Vansina 2003). Banana aDNA has been reported from 500-1300 AD figures from Ghana; however the current difficulties in using plant aDNA warrant caution in interpreting this evidence (Robinson et al 2017). Examples of early accepted evidence are limited to Mbandaka in the Inner Congo Basin, dating to cal AD 1330-1550 (See Fig.…”

Novel Substrates as Sources of Ancient DNA: Prospects and Hurdles

“…Based on their results, Foley et al claimed that sufficient DNA could be recovered merely by swabbing the inner surfaces of ceramic fragments that had been lying beneath the ocean floor for over two millennia. Robinson et al [ 101 ] also reported the recovery of aDNA from terracotta libation figurines from pre-colonial Ghana using a swabbing approach. Here, DNA from three plant types—plantain, pine and grasses—were identified using generic plant primers, recovering fragments up to 257 bp, significantly beyond the average length of DNA fragments they predicted by thermal age modeling.…”

“…A second challenge posed by unconventional substrates is that, unlike skeletal tissue, the taxonomic identity of the source(s) of the DNA (i.e., the species) is often unknown, for example in the metagenomic analysis of coprolites and calculus, or the analysis of artifacts, and thus more difficult to validate. Many of the aforementioned studies have used the BLAST application as a means of taxonomic identification for either metagenomic [ 34 , 136 ] or targeted amplicon sequences [ 101 , 135 ]. Although BLAST searches against the NCBI database is a widely used method for detecting sequence homology [ 233 ], taxonomic misidentification is a distinct possibility when working with short, damaged ancient DNA fragments.…”

Exploring prehistoric plant use by molecular analyses of Neolithic grave goods

“…Hofreiter et al 2001;Shanks et al 2005;McGovern and Hall 2016). Pottery, in particular, can absorb compounds and then protect them from outside contamination (Evershed 1993;Eerkens 2007;Hansson and Foley 2008;Foley et al 2012;Robinson et al 2017;Radford 2019).…”