5.2.4 DNA and the Mesolithic in Scotland

The last decade has seen a significant increase in the use of genetic analysis in order to reconstruct past population movements. This includes analyses based on both modern and ancient DNA. aDNA (ancient DNA) work is very unusual in Mesolithic contexts in Britain, Brian Sykes’ work with Cheddar Man is the most widely known but the recent reconstruction of the complete genome of a Mesolithic auroch from Derbyshire should be noted (Edwards et al. 2010). In the absence of aDNA the use of genetic analyses of modern populations is used in order to reconstruct past histories. This can include some very specific claims about the Mesolithic past and about the Mesolithic-Neolithic transition in the British Isles. For example, on the basis of modern population samples Sykes argues that ‘the Y-chronosonal evidence suggests that Mesolithic immigrants from Iberia went mainly to the western and southern British Isles, contributing initially about 24% of modern lines, which is rather similar to the maternal figure’ (Oppenheimer 2006, 152). Sykes argues for a clear distinction on genetic grounds for colonisation routes into eastern and western Scotland – the former ultimately deriving from the Balkans and the later from Iberia. Sykes reports that the Hebridean islands include high proportions of ‘clans’ (groups of related genetic sequences) ‘Jasmine and Tara’ that directly relate to the Neolithic expansion of agriculture, with these sequences in Scotland indicating population movement along the Atlantic fringes of Europe (Sykes 2006, 212). Whilst the frequencies of the Katrine ‘clan’, ultimately deriving from northern Italy c. 15000 years ago (an Alpine LGM refugia) are higher in Lewis than anywhere else in Scotland. Recent claims about the Mesolithic-Neolithic transition in Ireland are even more specific: ?About 13% of Irish mtDNAs belong to putative Neolithic clusters … there is an even distribution of putatively Neolithic haplogroups around the island, suggesting that females who arrived after the initial settlement were not restricted to east-facing regions. By contrast, however, Y-chromosome lineages of putative Near Eastern Neolithic origin … appear to be virtually absent from the west of Ireland’ (McEvoy et al. 2004, 695).

The use of modern populations to reconstruct past histories has been criticised on a number of grounds, including sample sizes and a failure to consider more recent histories of migration (for discussions of the relationships between archaeology and genetics in the specific context of early Holocene history see Pluciennik 2006; Thomas 2006). However, academic critiques have not significantly held back sales of popular books which offer a sense of antiquity and ancestry (for discussion see Nash 2007). The popular presentation of Cheddar Man’s supposed direct descendant, a school teacher from Cheddar, is indicative of the ways in which ancestry and senses of belonging are entangled with the reconstruction of genetic family trees.

The incorporation of genetics into anthropology and archaeology in general has been transformative (Pálsson 2007) and creates new possibilities. The resulting narratives sometimes feel unfamiliar and challenging. There can be a significant disconnect between those who use genetic data and those who do not, and at times, a sense that archaeologists feel that if they ignore the genetic interpretations the latter will fade away. Integrating the two sets of data is not straightforward but it is essential that Scottish archaeological research into the Mesolithic period actively engages with the interpretations offered by genetic research.   Recent genetic and isotopic work offers much more than straightforward detail of past migrations and will, it is to be hoped, be integrated into studies of early Prehistory in Scotland.

5.2.3 Dietary Reconstruction and Population Movements

Stable isotopes

Stable isotopes have a number of uses in archaeology. The concentrations of C-, N- and S-isotopes in human bone collagen can provide basic information on diet, such as the relative importance of terrestrial versus aquatic food sources. In practice, however, applications of dietary tracing using stable isotopes in the Scottish Mesolithic have been severely limited by the scarcity of human remains. No formal burials are known from Mesolithic sites, and the only dietary stable isotope results available are for disarticulated human remains from shell middens on the Isle of Oronsay (Richards and Mellars 1998; Richards and Sheridan 2000; Milner and Craig 2009). Sr- and O-isotopes in human bone/teeth can be used as tracers of population movement, but again Mesolithic applications in Scotland are constrained by the lack of human remains. O-isotope analysis can also be used to investigate the season of exploitation of fish and shellfish found in archaeological sites. While there have been some notable applications at Mesolithic sites around the Atlantic and Mediterranean coasts of Europe (e.g. Mannino et al. 2003; Colonese et al. 2009), the technique has hardly been used at all in Scotland (in spite of the abundance of suitable material); instead seasonality studies have relied on growth-line analysis of cockle shells (Deith 1983) or metrical analysis of fish otoliths (Mellars and Wilkinson 1980).