I just discussed again the genetic sweep that apparently has happened in Europe after the Neolithic strongly favoring the selection of alleles that allow the digestion of lactose (the sugar present in milk and often in other dairies) by adults. However our knowledge of ancient European genetics is probably not sufficient (nor that of lactose tolerance genetics
) and in any case the question remains, where did those lactase persistence (LP) alleles come from if all ancient Neolithic remains test negative?
An interesting possibility is opened by another recent study, not at all genetic in nature but rather bio-archaeological:
Lucy J. E. Cramp et al., Immediate replacement of fishing with dairying by the earliest farmers of the northeast Atlantic archipelagos. Proceedings of the Royal Society B 2014. Open access → LINK [doi:10.1098/rspb.2013.2372]
The appearance of farming, from its inception in the Near East around 12 000 years ago, finally reached the northwestern extremes of Europe by the fourth millennium BC or shortly thereafter. Various models have been invoked to explain the Neolithization of northern Europe; however, resolving these different scenarios has proved problematic due to poor faunal preservation and the lack of specificity achievable for commonly applied proxies. Here, we present new multi-proxy evidence, which qualitatively and quantitatively maps subsistence change in the northeast Atlantic archipelagos from the Late Mesolithic into the Neolithic and beyond. A model involving significant retention of hunter–gatherer–fisher influences was tested against one of the dominant adoptions of farming using a novel suite of lipid biomarkers, including dihydroxy fatty acids, ω-(o-alkylphenyl)alkanoic acids and stable carbon isotope signatures of individual fatty acids preserved in cooking vessels. These new findings, together with archaeozoological and human skeletal collagen bulk stable carbon isotope proxies, unequivocally confirm rejection of marine resources by early farmers coinciding with the adoption of intensive dairy farming. This pattern of Neolithization contrasts markedly to that occurring contemporaneously in the Baltic, suggesting that geographically distinct ecological and cultural influences dictated the evolution of subsistence practices at this critical phase of European prehistory.
Not only fish consumption was pretty much abandoned in Britain and Ireland with the arrival of Neolithic (only recovered under Viking influence many millennia later) but the most striking fact is that it was replaced by milk as main source of proteins.
This fact, considering that farmers studied in Central Europe and Iberia have systematically tested negative for lactase persistence, really opens an avenue for the possible origins of this nutritional adaptation because it is most unlikely that they were such notable dairy consumers without the corresponding digestive ability (even cheese may be harmful to lactose intolerant people unless it is aged, while yogurt was almost certainly not known yet in Europe).
Then again it is worth recalling that one of the first areas where the rs4988235(T) allele is found is in the southern areas of the Basque Country
, with clear signs of two different populations (one lactose tolerant and the other lactose intolerant) being still in the first stages of contact and mostly unmixed.
This leads us to the issue of Atlantic Megalithism (tightly associated to Atlantic Neolithic) and its still unsolved, but likely important, role in the conformation of the modern populations of Europe.
Whatever the case the first farmers of the islands were heavy dairy consumers, although in Britain (but not in Ireland and Man) they eventually derived into heavy meat eaters later on:
Prevalence of marine and dairy fats in prehistoric pottery determined from lipid residues. (a–f) Scatter plots show δ13C values determined from C16:0 and C18:0 fatty acids preserved in pottery from northern Britain (red circles), the Outer Hebrides (yellow circles) and the Northern
Isles of Scotland (blue circles), dating to (a) Early Neolithic, (b) Mid/Secondary expansion Neolithic, (c) Late Neolithic, (d) Bronze Age, (e) Iron Age and (f) Viking/Norse. Star symbol indicates where aquatic biomarkers were also detected. Ellipses show 1 s.d. confidence ellipses
from modern reference terrestrial species from the UK  and aquatic species from North Atlantic waters . (g–i) Maps show the frequency of dairy fats in residues from Neolithic pottery from (g) Early Neolithic, (h) the Middle Neolithic/Secondary expansion and (i) Late Neolithic. Additional data from isotopic analysis of residues from Neolithic southern Britain (n = 152) and Scotland (n = 104) are included [19,20].
The data of this study also suggests that the so much hyped high-meat “Paleolithic diet” is more of a Late Neolithic (Chalcolithic) thing, with the real hunter-gatherers of Europe being more into fish in fact.
Correction: I wrongly reported the main European lactase persistence SNP as rs13910*T, when it is in fact rs4988235(T) (already corrected in the text above) This was caused by the nomenclature used in the Sverrisdóttir paper, where it refers to it as -13910*T, which must be some other sort of naming convention. Thanks to Can for noticing.