UDK902'i2/'i5(4)''633/634'-575-i7 Documenta PraehistoricaXXXIII (2006) Clash of cultures? Archaeology and genetics Mark Pluciennik University of Leicester, UK M.Pluciennik@le.ac.uk ABSTRACT - This paper examines the ways in which genetic data have been used to interpret the transition to agriculture in Europe over the past two decades, and the relationship of these interpre- tations to more strictly archaeological explanations. It is suggested that, until recently, those working within the two disciplines have been using not only different data sets and methodologies, but also working within different disciplinary traditions which have inhibited communication and collabora- tion, and the production of a genuinely integrated field of 'archaeogenetics'. IZVLEČEK - V članku analiziramo pristope, ki so v zadnjih dveh desetletjih uporabljali genetske po- datke pri interpretaciji prehoda na poljedelstvo v Evropi ter odnos med temi interpretacijami in strikt- no arheološkimi razlagami. Ocenjujemo, da so raziskovalci v okviru teh dveh disciplin do nedavna uporabljali različne metodologije in serije podatkov ter delali znotraj različnih raziskovalnih tradi- cij. To je preprečevalo komunikacijo in sodelovanje ter izdelavo pristno integriranega področja 'ar- heogenetike'. KEY WORDS - Genetics; archaeology; Neolithic; rhetoric Introduction Archaeology has often had a strange and occasion- ally fraught relationship to science; the discipline is often described as straddling the humanities-science divide, and many of us would not be averse to being described as social scientists. Nevertheless, on occa- sions and especially, perhaps, in Anglo-American ar- chaeology, academics have sometimes tried to urge archaeological practice more forcefully in the direc- tion of harder science, or alternatively and perhaps in reaction towards the 'softer' humanities. Such ar- guments have tended to be about philosophical and epistemological positions rather than methodological ones, and have their basis in the nineteenth century. For example, in 1858 Johann Droysen proposed that there were three types of systematic knowledge: the speculative, which related to the kind of knowledge produced by philosophy and theology; the mathema- tical or physical, grounded in logic and in empirical facts; and the historical. He suggested that these three realms of knowledge had what he called three 'essences' or characteristics: respectively, to know (Wissen), to explain (Erklären) and to understand (Verstehen). The last two roughly equated respecti- vely to the 'hard sciences' - physics, chemistry, bio- logy and so forth - and the 'humanities'. The social sciences including archaeology can, however, be seen to partake of both 'essences'. Archaeology is an unusual discipline in drawing on both types of 'knowledge' and their associated theories more or less equally and in an internally-integrated manner; other disciplines such as geography, for example, have ended up with divisions which more or less equate to these distinctions, with physical and hu- man geography. The history of archaeological theory and indeed its disciplinary culture and even status can thus in part be characterised as leaning towards one side or the other - towards science or the hu- manities for its inspiration. As usual, though, the picture was and is more com- plicated: archaeologists are perhaps better described as theoretical magpies. Archaeologists of any persua- sion routinely use statistical analysis and scientifi- cally obtained environmental data, for example. In the Anglo-American world, 'scientific' New and pro- cessual archaeologists were interested in social and cultural phenomena, and not just in explaining energy extraction from the environment. Scientific methodologies and procedures and data are impor- tant to all of us; the necessity to be something of a jack-of-all-trades, having to be aware of isotope ana- lysis and cultural theory, Bayesian modelling and social anthropology, is what makes the discipline particularly challenging. It has therefore been inte- resting to observe disciplinary reactions when a new and undoubtedly scientific technique from a hitherto unrelated discipline, which I shall here call 'genetics', came to impinge on archaeological understandings of the past. This seems to have been a particularly divisive area, particularly in addressing the question of the Meso- lithic-Neolithic transition, primarily in Europe, and which I shall use as my case study in this paper. By and large, archaeologists were hostile to the out- comes and apparent implications of relevant genet- ic research: very few archaeologists embraced the genetic data (and controversial 'evidence' from lin- guistics) with fervour. Equally, geneticists often ap- peared as though they considered archaeological data irrelevant for studying the prehistoric past. Why should this be? After all, this particular rela- tionship started as collaboration. In this paper I will mainly examine some of the rhetoric and practices associated with this debate as a way of considering whether there are, despite archaeology's hybrid po- sition, fundamentally different disciplinary cultures involved. I shall conclude by looking at some of the implications for methodologies - not for genetics or molecular biology, which I am totally unqualified to offer - but rather ways of collaboration and means of approach. Genetics and archaeology Thirty five years ago (and subsequently elaborated in detail), Albert Ammerman and Luigi-Luca Cavalli- Sforza (1971; 1973; 1984) presented an interesting idea relating to a potential new source of evidence about the spread of farming in Europe. Discussing the apparent rate of spread of the Neolithic, and ex- plaining this through an initially exogenous popula- tion expansion associated with early farming in Eu- rope, they mentioned the 'possible genetic implica- tions of the model'. "The population wave of advance accompanying the spread of early farming should be reflected, if this [demic diffusion] explanation is the correct one, in the genetic compositions of the resulting populations." (Ammerman and Cavalli-Sforza 1971.687) This was - and is - a powerful idea. Since that time there has been a huge amount of genetic data and analysis published which is often stimulating, which has undoubtedly raised new questions and perhaps offered new insights, through looking not just at overall genetic frequencies of classical markers such as blood proteins, but subsequently also at different regions and sites within the genome, and suggesting genetic histories - phylogenetics - and putative dates for mutations and haplotypes, and consequently hi- stories of haplogroups; and of differences between female-inherited (mtDNA) and male-inherited (Y- chromosome) genetic material, for example. For the purposes of this paper, though, it is worth noting that the question as posed initially by Ammerman and Cavalli-Sforza was primarily an archaeological question: genetic information, it is suggested, may be able to illuminate the process of transition, given certain primarily demographic conditions. The demo- graphic modelling was in part based on ethnographic data relating to hunter-gatherer and small-scale far- ming societies. Since then, and especially since the 1990s, the disci- pline of what some call 'archaeogenetics' (Renfrew 2000.3) has seen the production of large numbers of datasets and numerous interpretations in relation to the transition to and spread of farming, especially in Europe, as well as much evidence related to migra- tory population movement elsewhere - Polynesia and the Americas in particular (see e.g. Jones et al. 1999; Renfrew and Boyle 2000). So far, these data- sets have been derived primarily from modern po- pulations, and the information explored in terms of their phylogenies - the genetic histories - and mo- dern spatial distribution. Ancient DNA, which would appear to offer much more specific information from individuals and groups of individuals who can be placed, culturally-situated and dated archaeologically, is rarely sought, mainly because of the potential pro- blems of identifying contamination (but see e.g. Chandler et al. 2005; Haak et al. 2005). This is not the place to explore the use (and abuse) of such data in detail: but see Mirza and Dungworth 1995; Fix 1996; Pluciennik 1996, Sims-Williams 1998; Mac- Eachern 2000; Zvelebil 2000; Bandelt et al. 2002). There has been a persistent and major problem of the conflation of genetic, linguistic and cultural 'en- tities' and (pseudo-)archaeology, with the assump- tion that these forms of biology, culture and iden- tity almost inevitably go together (see Moore 1994; Terrell and Stewart 1996), at least until 'modern' times. I would suggest that archaeologists already 'knew', and certainly by the 1980s, that the process of the Mesolithic-Neolithic transition in Europe was com- plex socially, culturally and therefore almost cer- tainly, biologically. However, one gets little sense of this from looking at the genetic literature, until very recently. And even here the methodology seems, to many archaeologists, rather upside-down. 'We would argue that it would be worthwhile to turn the scien- tific procedure around', argued Pinhasi et al. (2000. 55). That is, the apparent injunction to start with a simple model - even though obviously, archaeologi- cally-speaking, wrong - is presented as a methodo- logical necessity. In the case examined here, it is that the spread of farming represents either population expansion by genetically-distinct farmers, or the adoption of farming by genetically distinct foragers. To be fair, a few later publications - led by archaeo- logists - have asked whether the genetic and other biological signatures supported archaeological inter- pretations on a regional scale (e.g. Lalueza Fox 1996; Jackes et al. 1997; Pinhasi and Pluciennik 2004; Chandler et al. 2005). Another and arguably more productive approach would be, for example, to mo- del the relevant genetic histories in terms of archa- eological understandings of the processes involved (in the plural!), and at least ask what kinds of gene- tic outcomes we might expect. Yet after 20 and more years of research, this kind of question is apparently only now beginning to be asked. It is these kinds of intellectual propensities and resistances which sug- gest that at least some of the tensions between 'ar- chaeological' and 'genetic' explanations of the Meso- lithic-Neolithic transition are best explained as mat- ters of disciplinary preferences and traditions of thought and practice; that is, of culture. The great divide One of the striking aspects of the relevant literature is that for a very long time the 'archaeology' was swept aside and the debate was very largely driven by the genetic data - and hence, de facto, by the ge- neticists. This was so even though we had here a po- tentially powerful new set of techniques for saying something about the past, although exactly what they 'say' certainly is not yet clear. Thus in relation to the Neolithic in Europe (the area where many of the best data sets tended to come from), the ap- proach in the publications basically became a ques- tion of supporting (or much more rarely disagreeing with) this model of 'demic diffusion'. Even in a re- cent review, this is still how the question is charac- terised: 'The primary issue remains whether agri- culture spread by contact or by farmers moving into Europe' (Armelagos and Harper 2005.109). So po- werful was this drive that some archaeologists, too, decided that the 'truths' of genetics were more plau- sible than those suggested by the archaeology. The debate became strongly polarised: in general, gene- ticists (and a few others) accepted the 'fact' of demic diffusion and published evidence which apparently supported it. Meanwhile, many archaeologists had been moving just as strongly away from demic dif- fusion models and were increasingly arguing for the Mesolithic-Neolithic transition as a highly variable socio-cultural phenomenon (including demographic and other biological processes) on the regional, let alone the continental scale (Zvelebil 1986a; Price 2000). But they were not - and I include myself here - engaging with geneticists through collaboration and joint publication; instead, there were critical papers and conference sessions in which archaeologists were primarily talking to archaeologists, in the same way that geneticists were primarily writing for and spea- king to other geneticists. Thus there were a series of papers, referred to above, critical of genetic interpre- tations which by and large ignored the archaeology and continued to confuse and conflate biological con- structs - genetic histories - with social entities, inclu- ding linguistic and ethnic groups and names. This polarisation is seen in Table 1. Here some pa- pers by geneticists and published primarily in jour- nals in that discipline in the 1980's and l990's are summarised. The fact that these are generally multi- authored is, of course, itself an aspect of disciplinary culture: the convention is for entire laboratory teams to be named as authors. More interesting, perhaps, is the fact that archaeologists were rarely involved in producing these papers: their 'contribution' was limi- ted to a very few items (and those often out of date) cited in the bibliographies. There were notable ex- ceptions: I would single out Martin Richards (see this volume), and also note that where archaeologists were involved (such as Colin Renfrew) appropriate archaeological and other citations were frequent, va- rious and up-to-date. Nevertheless, the widespread Authors Date Geneticists Archaeologists (linguists) Subject Archaeology references (n) Torroni et al. 1998a 11 - Late Paleolithic re-colonization 1990 (1) Wilkinson-Herbots et al. 1996 4 - Late Palaeolithic re-colonization 1986> 1995 (2) Sajantila et al. 1995 13 Genes & languages 1987, 1988 (2) Torroni et al. 1998b 11 - Late Palaeolithic re-colonization 1990 (1) Sokal & Menozzi 1982 2 - Neolithic diffusion ^71 1973 (2) Richards et al. 1996 10 - Palaeolithic & Neolithic diffusion 1983-1995 (10) Semino et al. 1996 5 - Neolithic diffusion 1889, 1943, 1989 (4) Pult et al 1994 6 - Modern humans in Europe - Rendine et al. 1986 3 - Neolithic diffusion 1953-1984 (8) Barbujani et al. 1994 3 1 Neolithic diffusion 1971-1992 (17) plus linguistics Jones 1991 1 - Neolithic diffusion - Sokal et al. 1991 3 - Neolithic diffusion 1953-1991 (7) Tab. 1. problem amongst geneticists of their ignorance of socio-cultural processes and archaeological interpre- tations and debates - or perhaps the failure to see their possible relevance - is best epitomised by the astonishing paper by Robert Sokal and colleagues. Rather than seeking archaeological advice, he pre- ferred to use a 'European ethno-history database, de- veloped in our laboratory' which 'documents the known locations and movements of 891 ethnic units over the last 4000 years' (Sokal et al. 1993.56). The database purported to 'list the name of a "gens" or tribe (or that of an archaeological horizon in the case of prehistoric records...)' (Sokal et al. 199357). Thus, even though Renfrew (2000.3) claimed that the new discipline of archaeogenetics involved 'the study of the human past using the techniques of mo- lecular genetics', it tended to be a very partial view. Renfrew continued: 'In practice this is likely to in- volve the collaboration of molecular geneticists with archaeologists, anthropologists, historical linguists and climatalogists'. But so far and despite the inte- grative work of Renfrew and other grand theorists such as Peter Bellwood (Bellwood 2001; 2004; Bel- lwood and Renfrew 2002; Renfrew 1992; 1996; 1997) and indeed Cavalli-Sforza himself (1996), such collaboration has not been substantiated, at least in terms of joint authorship, with rare exceptions (e.g. Barbujani et al. 1994). Indeed, even in the volume Archaeogenetics itself, the division between papers by archaeologists, and papers by geneticists, is as strong as elsewhere. Many other similar papers have been published, of course: those summarised in Table 1 are merely a se- lection of those claiming to deal explicitly with an archaeological issue, namely the transition to farm- ing in Europe, or occasionally, the late Palaeolithic re- colonisation of post-Last Glacial Maximum northern Europe. These latter are included because they often discuss the 'Mesolithic' and 'Neolithic' input as com- pared with 'Palaeolithic' contributions to gene pools. Also excluded are those papers which only allude to possible 'prehistoric scenarios' in passing, and are primarily methodological or papers descriptive of ge- netic data, and for which the audience will be other geneticists. Other papers not included here examine the supposed relationships between genes and lan- guages. While one could show a similar table for re- levant papers written by archaeologists, it would not be so informative. Inevitably, there were up-to-date references for genetics papers (because that is what they were criticising), but (apart from those of Am- merman and Cavalli-Sforza) there were virtually no joint cross-disciplinary papers in the 1980s and very few in the 1990s, but more in the last five years and other evidence of efforts to bring archaeologists and geneticists together (e.g. Bentley et al 2003; ESF 2004; Gamble et al. 2005; this volume). Apart from the methodological and epistemological facts of the matter, we should also be interested in this as a socio-political phenomenon. Why did the 'debate' unfold in the way that it did? Where are we now? And where we might realistically look for synergies between archaeology and genetics? Rhetoric and politics There are other contexts for this, which perhaps also suggests that other more subtle socio-politics are playing a role here. First of all, we can note that of the broadest set being examined, the most high pro- file archaeogenetics papers and the greatest volume of work related to either big issues (the origins of modern humans and Neanderthal DNA; origins and spread of agriculture; origins of contemporary peo- ples such as Polynesians or Native Americans): appa- rently foundational episodes, rather than the impli- cations of day-to-day demographics and genetic ex- change - sex - across or within group boundaries. Overall there are three major groups of relevant pa- pers in order of volume: O Papers describing the structure of genetic mate- rial and distributions both phylogenetically and geographically: this is basically about genetic data production; © Papers dealing with methodologies and model building; © Papers dealing with histories: these tend to be stated in terms of 'Neolithic', or 'Indo-European' contributions; only recently have geneticists star- ted to model admixtures. The emphasis in the last group seems to me to de- monstrate the well-known prevalence of historical questions dealing with origins - what led to 'us' (e.g. Piazza 1993). Were this archaeology, one might ar- gue that this focus also relates to the continued in- fluence of stadial social evolution, and hence on ap- parent moments of transition understood as radical change. In archaeology these biases have at least been considered and critiqued, while geneticists, in a different tradition, typically, are not necessarily au fait, or used to dealing with such political and critical issues of structures of thought and narratives. How- ever, it seems that within genetic studies the more likely explanation is that, to begin with, at least, the methodological need to distinguish between popula- tions led to and maintained the focus on the 'new' or distinctive, genetically speaking. Other factors In the late 1980s Ammerman (1989) and Zvelebil (1989) exchanged views on how to approach the Mesolithic-Neolithic transition in Europe, and what was structuring those views. Ammerman suggested, broadly, that the bias towards and interest in proces- ses of cultural diffusion and adoption of Neolithic traits by indigenous forager populations a la Zvele- bil was a result of post-colonial guilt within Europe (see also Keeley l992). Whatever one's view about the influence of politics on archaeological interpre- tations, no such doubts assailed many looking at demic diffusion from the genetic point of view. The important thing about the Mesolithic-Neolithic tran- sition was the incoming, novel populations: the inte- rest was in the 'contribution' of farmers, a bias which has been noted in the construction of modern Euro- pean identities (Zvelebil 1996). Thus presentations tended to be couched in terms of Neolithic (or Indo- European) immigrants, rather than of mixing, or hy- bridism. This was so when estimates of the 'Neoli- thic contribution' through a 'wave of advance' were higher than the consensus is now - in Cavalli-Sforza et al's famous map obtained from Principal Compo- nents Analysis it was suggested that the Neolithic contribution to the gene pool might be of the order of 28% (