more lactase references

KurdishDNA: Lactose Tolerance

Leherensuge: Actual lactase persistence more common than genes predict

the genetics of lactase persistence | BioBlog

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“The Human Environment and the Vitamin D Compromise” by George Chaplin and Nina G. Jablonski

Year-round human habitation of environments with highly seasonal regimes of ultraviolet B radiation UVB depended on adaptive complexes of biological and cultural traits to ensure adequacy of vitamin D. Perturbations of such adaptive complexes resulting from changes in the physical environment, human behavior and culture, or both have had unexpected and untoward consequences for health. Scotland is an excellent case study of the changing nature of human biocultural adaptation to low-UVB environments. Occupation of Scotland after the last Pleistocene glaciation event about 14,000 YBP was made possible by maximally depigmented skin, which facilitated cutaneous biosynthesis of vitamin D3, and by a diet that emphasized foods rich in vitamin D. Changes in human subsistence and diet began with the introduction of agriculture and grazing about 5,000 YBP and accelerated greatly in the last 200 years through industrialization and urbanization. The resulting changes in domiciles, patterns of daily activity and behavior, and diet have led to reduced exposure to UVB and reduced consumption of vitamin D–rich foods. This has perturbed the “vitamin D compromise,” an adaptive complex established in Scotland during the Mesolithic and Neolithic. We describe the UVB environment of Scotland from remotely sensed data and combine these data with information from the archaeological record to describe the vitamin D compromise in Scotland. Changes in human exposure to UVB and vitamin D consumption, which occurred as the result of urbanization and the dietary shift away from the consumption of oily fish, are traced. Vitamin D deficiency contributes to increased disease prevalence in Scotland, including that of the autoimmune disease multiple sclerosis, a debilitating neurodegenerative disease caused by demyelination of the central nervous system. These conditions have created an “imperfect storm” of poor health that should command the attention of public health experts and policy makers.

via “The Human Environment and the Vitamin D Compromise” by George Chaplin and Nina G. Jablonski.

Iodine | Greying Wanderer

We’re not going to find new strange deficiencies. However we might well find perfectly straightforward deficiencies that didn’t used to be deficiencies if for example people’s diet changed dramatically and the consumption of some fundamental component of brain development i.e. iodine, dramatically declined with that dietary change e.g. a dramatic decline in iodine rich dairy consumption among people of north European descent if it wasn’t compensated for in some way like with the addition of iodine to salt.If correct then as Germany started the process of adding iodine to salt in 1981 there will be a cohort of Germans in their 20s coming through now so we should find out soon enough if there’s been an effect.A point worth considering for Germans is they changed their education system after their low results when PISA first started. If the iodine idea is correct then they may have made a mistake.

Actually we might find strange new factors in underlying IQ differences if the basic idea was accepted and focus and research shifted to groups who *ought* to have the same average IQ (because genetically very similar, very close geographically etc) but for some reason they don’t.

Just to add, the Netherlands started adding iodine to salt in 1968, Belgium in the 90s, France 60s IIRC, Denmark 2000s, Britain never.

Map of surface area by patents

http://www.worldmapper.org/images/largepng/167.png

Imagine Britain or Germany were proportionally the same as Japan (like they used to be?)

via More on Deafness | West Hunter.

For what they were… we are: Lactase persistence genetics in Africa

Abstract

In humans, the ability to digest lactose, the sugar in milk, declines after weaning because of decreasing levels of the enzyme lactase-phlorizin hydrolase, encoded by LCT. However, some individuals maintain high enzyme amounts and are able to digest lactose into adulthood (i.e., they have the lactase-persistence [LP] trait). It is thought that selection has played a major role in maintaining this genetically determined phenotypic trait in different human populations that practice pastoralism. To identify variants associated with the LP trait and to study its evolutionary history in Africa, we sequenced MCM6 introns 9 and 13 and ∼2 kb of the LCT promoter region in 819 individuals from 63 African populations and in 154 non-Africans from nine populations. We also genotyped four microsatellites in an ∼198 kb region in a subset of 252 individuals to reconstruct the origin and spread of LP-associated variants in Africa. Additionally, we examined the association between LP and genetic variability at candidate regulatory regions in 513 individuals from eastern Africa. Our analyses confirmed the association between the LP trait and three common variants in intron 13 (C-14010, G-13907, and G-13915). Furthermore, we identified two additional LP-associated SNPs in intron 13 and the promoter region (G-12962 and T-956, respectively). Using neutrality tests based on the allele frequency spectrum and long-range linkage disequilibrium, we detected strong signatures of recent positive selection in eastern African populations and the Fulani from central Africa. In addition, haplotype analysis supported an eastern African origin of the C-14010 LP-associated mutation in southern Africa.

via For what they were… we are: Lactase persistence genetics in Africa.

Immediate replacement of fishing with dairying by the earliest farmers of the northeast Atlantic archipelagos

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.

Figure 1.

Prevalence of marine and dairy fats in prehistoric pottery determined from lipid residues. (af) 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 [19] and aquatic species from North Atlantic waters [13]. (gi) 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].

Figure 2.

(a) Partial high-temperature gas chromatograms showing total lipid extracts from three sherds above mass chromatograms from aliquots analysed using GC/MS operated in SIM mode for the detection of (b) C18–C22 DHYAs (as tris-trimethylsilyl derivatives) and (c) C18–C22 APAAs (as methyl esters; electronic supplementary material, tables S1 and S2). Components were identified based upon the presence of identical chromatographic peaks for the characteristic fragment ions and molecular ions at the expected retention times. Residue (i) is from the Neolithic settlement at Braes o’Habreck on Wyre, the Orkney Isles; (ii) is from Cille Pheadair, South Uist; and (iii) is from Jarlshof, Shetland; only (ii) and (iii) contain detectable marine biomarkers, with (iii) displaying the strongest signatures. Filled circles represent free fatty acids with carbon number x and degree of unsaturation y. Retention window: (a) 5–35 min, (b) 23–30 min and (c) 24–36 min.

Figure 3.

Multi-proxy palaeodietary information from the Western and Northern Isles of Scotland and mainland northern Britain. (a) Mean δ13C values from bulk human bone collagen [2127] with error bars showing 1 s.d. (b) Proportions of fauna bones in prehistoric assemblages determined from NISP. Owing to the over-representation of shellfish, this class has been excluded; however, shellfish comprise just 1.3% of Neolithic assemblages. Faunal skeletal assemblages from the Mesolithic from this region are sparse, and comparable published datasets almost non-existent; the Mesolithic bar here therefore represents the faunal data from a single site of Northton, Isle of Harris [28]. Although no marine mammals were recorded at this site, a high number were recorded at Oronsay [29]. (c) The percentage of pot lipid residues containing components diagnostic of aquatic fat processing and (d) the percentage of pot residues that were classified as dairy fats.

Immediate replacement of fishing with dairying by the earliest farmers of the northeast Atlantic archipelagos.

Overpopulation Is Not the Problem – NYTimes.com

The science of human sustenance is inherently a social science. Neither physics nor chemistry nor even biology is adequate to understand how it has been possible for one species to reshape both its own future and the destiny of an entire planet. This is the science of the Anthropocene. The idea that humans must live within the natural environmental limits of our planet denies the realities of our entire history, and most likely the future. Humans are niche creators. We transform ecosystems to sustain ourselves. This is what we do and have always done. Our planet’s human-carrying capacity emerges from the capabilities of our social systems and our technologies more than from any environmental limits.

Overpopulation Is Not the Problem – NYTimes.com.

The Good-Luck Charm That Solved a Public-Health Problem – Eleanor Smith – The Atlantic

Warding off anemia with small iron fish

Charles, a Canadian epidemiologist, knew that iron-rich foods and supplements were too expensive for most rural Cambodians. Even cast-iron pots, which safely transmit iron to food as it cooks, were out of reach. But he wondered whether a small piece of iron placed in a standard aluminum pot would have a similar iron-releasing effect. To test his hypothesis, Charles distributed blocks of iron to local women, telling them to place the blocks in their cooking pots before making soup or boiling drinking water. The women promptly put them to use as doorstops.

After talking with village elders, Charles learned of a fish known as try kantrop, which the locals ate frequently and considered a symbol of good luck. When he handed out smiling iron replicas of this fish, women started cooking with them. “People associated it with luck, health, and happiness,” he says. Within 12 months, Charles reports, anemia in villages where the fish was distributed virtually disappeared.

The genius of the Lucky Iron Fish is that it does not have to be shaped like a fish. “If we were to go to sub-Saharan Africa,” says Charles, “or a dry area where fish is not an important part of the diet, we could very easily change it to a different symbol of luck.”

The Good-Luck Charm That Solved a Public-Health Problem – Eleanor Smith – The Atlantic.