There are many other issues of interest in these fascinating reviews. For instance, the treatment of Africa in the review by Campbell and Tishkoff [19xThe evolution of human genetic and phenotypic variation in Africa. Campbell, M.C. and Tishkoff, S.A. Curr. Biol. 2010; 20: R166–R173Abstract | Full Text | Full Text PDF | PubMed | Scopus (61)See all References[19] notes the remarkably long duration of the correlation between genetic and cultural and linguistic similarities in some African populations, such as the African pygmies and several Khoesan-speaking populations, which may have diverged more than 35 kya [20xThe genetic structure and history of Africans and African Americans. Tishkoff, S.A., Reed, F.A., Friedlaender, F.R., Ehret, C., Ranciaro, A., Froment, A., Hirbo, J.B., Awomoyi, A.A., Bodo, J.M., Doumbo, O. et al. Science. 2009; 324: 1035–1044Crossref | PubMed | Scopus (565)See all References[20]. Very similar conclusions on this theme have been reached [21xThe dawn of human matrilineal diversity. Behar, D.M., Villems, R., Soodyall, H., Blue-Smith, J., Pereira, L., Metspalu, E., Scozzari, R., Makkan, H., Tzur, S., Comas, D. et al. Am. J. Hum. Genet. 2008; 82: 1130–1140Abstract | Full Text | Full Text PDF | PubMed | Scopus (208)See all References, 22xMaternal traces of deep common ancestry and asymmetric gene flow between Pygmy hunter-gatherers and Bantu-speaking farmers. Quintana-Murci, L., Quach, H., Harmant, C., Luca, F., Massonnet, B., Patin, E., Sica, L., Mouguiama-Daouda, P., Comas, D., Tzur, S. et al. Proc. Natl. Acad. Sci. U S A. 2008; 105: 1596–1601Crossref | PubMed | Scopus (94)See all References]. It seems remarkable that groups, which one might refer to as ethnic groups, could have retained linguistic and genetic identities over so long a period of time. Of course, most aspects of those linguistic identities are not available to us as languages change, although the persistence of click consonants in some divergent African hunter-gatherers seems to be one of them that is.Remarkably, also, these observations are not restricted to the remote periods, equivalent to the periods of initial colonisation and its aftermath in Europe and South Asia. They also extend into the more recent periods. In Africa, genetic signatures of historic and prehistoric migration events are visible in several instances, not least the geographic expansion of the Bantu Niger-Kordofanian speakers from Nigeria and Cameroon first into the rainforests of equatorial Africa and then into eastern and southern Africa within the past 5000 years. So, one is presented here with a number of correlations in Africa between genetic and linguistic prehistory, some of them seemingly going back some 35,000 years. This example perhaps seems to offer more grounds for optimism than some distinguished linguists would allow, also in other continents where questions of time depth in historical linguistics are concerned [23xWhy linguists don't do dates: evidence from Indo-European and Australian languages. McMahon, A. and McMahon, R. See all References, 24xThe problem of time depth. Renfrew, C. : ix–xivSee all References]. Indeed, there are indications that the application of phylogenetic methods in this area may prove fruitful [25xIntroduction. Renfrew, C. and Forster, P. : 1–10See all References[25]. As Manfred Kayser notes in his review of Oceania [11xThe human genetic history of Oceania: near and remote views of dispersal. Kayser, M. Curr. Biol. 2010; 20: R194–R201Abstract | Full Text | Full Text PDF | PubMed | Scopus (52)See all References[11], Bayesian phylogenetic analysis of lexical data undertaken there by Gray, Drummond and Greenhill [26xLanguage phylogenies reveal expansion pulses and pauses in Pacific settlement. Gray, R.D., Drummond, A.J., and Greenhill, S.J. Science. 2009; 323: 479–483Crossref | PubMed | Scopus (237)See all References[26] revealed a Taiwanese origin of the Austronesian languages about 5200. This can, as he discusses, be related to the molecular genetic evidence, although this is admittedly quite complex. A comparable analysis by Gray and Atkinson [27xLanguage-tree divergence times support the Anatolian theory of Indo-European origin. Gray, R.D. and Atkinson, Q.D. Nature. 2003; 426: 435–439Crossref | PubMed | Scopus (326)See all References[27] applied to the Indo-European languages of Europe and South Asia suggests a time depth of the order of 9000 years for their original divergence, much greater than posited by many Indo-European linguists. It is also much more in harmony with a concomitant spread of farming and language as a mechanism for generating the ultimate geographical extent of this language family [28xThe ‘Emerging Synthesis’: the archaeogenetics of farming/language dispersals and other spread zones. Renfrew, C. : 3–16See all References[28].Perhaps the most important general point that can be drawn from the reviews assembled in this special issue might be that we have not yet learnt how to interpret the data very effectively. A number of contributors have commented upon the need for simulation studies, based upon explicit models which might allow the testing of specific scenarios [29xIntroduction. Matsumura, S. and Forster, P. : 1–6See all References[29], and this is likely to be one of the most important future research directions. Above all, the pace of research is now so fast that new insights are soon likely to become available. These are early days in the field of archaeogenetic research, and I predict that over the next twenty years or so a more coherent synthesis of the data from genetics, archaeology and linguistics is likely to emerge than we can yet envisage.