Eating, and eating well

Credit: tuchodi

Happy Thanksgiving Day to all the Americans out there. This is a day to loosen the belt a bit, but after the Holidays you probably want to think about slimming back. So, ScienceDaily, Obesity Riddle Finally ‘Solved’, and, Diets with High or Low Protein Content and Glycemic Index for Weight-Loss Maintenance. The upshot seems to be that a high protein-low (refined) carb diet worked best in a large sample of Europeans.

Myself, I was in the 155-165 pound range between 2000 and 2007. 2008-2010 I’ve been in the 140-150 range, and usually closer to the low end than the high. I went from a waist size in the 31-33 inch range to 28-30 range (I wear 28s regularly now). I’m moderately active in that I walk a lot, but I have totally turned away from refined carbs. I am not a religious ‘Paleo’, but I do track glycemic indices and glycemic loads for various foods rather closely. That being said, different people have different biologies. I think that’s important to remember. As a South Asian I have a higher risk for type 2 diabetes, so I’m particularly vigilant about sugar and other variables which increase my probabilities for chronic diseases. If I was a Northern European I might have different priorities, and chill out a little bit about dessert. Life is about trade-offs, and pleasures do often have costs. I am not much of a sweet-tooth, and I’m genetically predisposed to type 2, so my aversion toward sweets is a rather simple calculation. Others may have different outcomes performing the same operations because of different inputs. The answer to a riddle may vary depending on who is asking.

We were all Africans…before the intermission

modelhumanQuick review. In the 19th century once the idea that humans were derived from non-human ancestral species was injected into the bloodstream of the intellectual classes there was an immediate debate as to the location of the proto-human homeland; the Urheimat of us all. Charles Darwin favored Africa, but in many ways this ran against the cultural grain. The theory of evolution was birthed before the highest tide of the age of white supremacy and European hegemony, and Darwin’s model had to swim against the conviction that Africans were the most primitive of the colored races. After the waning of the ideological edifice of white supremacy, and the shock it received during and after World War II, the debates as to the origin of humanity still remained contentious and followed the same outlines (though without the charged normative inferences). But as the decades wore on many more researchers began to believe that Darwin was correct, and that the origin of humanity lay in the African continent. First, the deep origin of the human lineage in Africa was accepted, but eventually a more recent expansion out of Africa was argued for by one school. The turning point in these academic disputes was the popularization of the “mitochondrial Eve” theory of the 1980s.

What some paleontologists had long argued, that anatomically modern humans have their locus of origin in Africa, was supported now by research from genetics which indicated that Africans were the most basal clade of humans on a continental scale, so that non-Africans could be conceived of as a subset of Africans. From this originates the chestnut of wisdom that Africans have more genetic diversity than all other human populations combined. By the year 2000 one could say that the “Out of Africa” triumphalism had proceeded to the point where an almost exterminationist model had taken hold when it came to the relationships of anatomically modern H. sapiens, and other groups which had evolved outside of Africa over the past million or so years, such as the Neandertals.

ResearchBlogging.orgBut the theoretical dichotomies were too coarse and absolute as it turns out. A division between multiregionalist phyletic gradualism, where H. sapiens evolved out of its hominin ancestors concurrently on a world wide scale, and a model of rapid expansion of one tribe in Africa to replace all others in totality, may have been warranted in the age of classical genetics and a morphometric analysis, but now we can look at the raw genomic material in a more fine-grained fashion. In fact, we can now look at the genomic patterns of variation among extinct hominins! Though there have long been hints that the expansion-and-replacement paradigm was too extreme from the genetic and morphological data, with the publication last spring in Science of a paper which made the claim for admixture between Neandertals and non-Africans in the range of 1-4% in all non-African groups based on a comparison of Neandertal and modern human genetic variation, one can dismiss absolutist expansion-and-replacement as self-evidently true orthodoxy. But one orthodoxy has no given way to another, and the shock to the old models presented by the data has not resulted in the coalescence of new robust paradigms. We live in a time of scientific troubles, so to speak.

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The inevitable social brain

ResearchBlogging.orgOne of the most persistent debates about the process of evolution is whether it exhibits directionality or inevitability. This is not limited to a biological context; Marxist thinkers long promoted a model of long-term social determinism whereby human groups progressed through a sequence of modes of production. Such an assumption is not limited to Marxists. William H. McNeill observes the trend toward greater complexity and robusticity of civilization in The Human Web, while Ray Huang documents the same on a smaller scale in China: A Macrohistory. A superficial familiarity with the dynastic cycles which recurred over the history of Imperial China immediately yields the observation that the interregnums between distinct Mandates of Heaven became progressively less chaotic and lengthy. But set against this larger trend are the small cycles of rise and fall and rise. Consider the complexity and economies of scale of the late Roman Empire, whose crash in material terms is copiously documented in The Fall of Rome: And the End of Civilization. It is arguable that it took nearly eight centuries for European civilization to match the vigor and sophistication of the Roman Empire after its collapse as a unitary entity in the 5th century (though some claim that Europeans did not match Roman civilization until the early modern period, after the Renaissance).

It is natural and unsurprising that the same sort of disputes which have plagued the scholarship of human history are also endemic to a historical science like evolutionary biology. Stephen Jay Gould famously asserted that evolutionary outcomes are highly contingent. Richard Dawkins disagrees. Here is a passage from The Ancestor’s Tale:

…I have long wondered whether the hectoring orthodoxy of contingency might have gone too far. My review of Gould’s Full House (reprinted in A Devil’s Chaplain) defended the popular notion of progress in evolution: not progress towards humanity – Darwin forend! – but progress in directions that are at least predictable enough to justify the word. As I shall argue in a moment, the cumulative build-up of compelx adaptations like eyes strongly suggest a version of progress – especially when coupled in imagination with of the wonderful products of convergent evolution.

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The rise of men & the fall of the non-men

Dienekes Pontikos ruminates on the changes in human genetic variation on a world-wide scale over the past 10,000 years based on an MDS plot of East Eurasian genetic variation which he generated. I’ve taken his plot and added geographical labels, so you can see the difference in scale between geography and genetics in terms of distance:


He argues:

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Eurogenes 500K SNP BioGeographicAncestry Project

Since I have been promoting the Dodecad Ancestry Project, it seems only fair to bring to your attention Eurogenes 500K SNP BioGeographicAncestry Project. The sample populations are a bit different from Dodecad, but again ADMIXTURE is the primary tool. But the author also makes recourse to other methodologies to explore more than simply population level variation. For example, his most recent post is Locating and visualizing minority non-European admixtures across our genomes:

Imagine, for example, a white American carrying a couple of tiny segments of West African origin, from an ancestor who lived 250 years ago, and an eastern Finn with no Asian ancestors in the last 4000 years or more. If we run an inter-continental ADMIXTURE analysis with these two, it’s very likely the American will score 100% European, while the eastern Finn will probably come out around 9% North and East Asian due to really old Uralic influence.

That sort of thing isn’t a huge problem when comparing the genetic structure of populations. Obviously, overall, eastern Finns rather than white Americans are genetically closer to North Asians, and that’s basically what ADMIXTURE picks up. However, if the focus is also on individuals, this certainly can become an issue. Our hypothetical American might be aware of that African ancestor, with solid paperwork backing up their genealogical connection, but he’s pulling his hair out because nothing’s showing up via genetic tests.

So let’s take a look at a real life example of how RHHcounter can pick up segments of potentially recent Sub-Saharan African origin…

Olivia Munn & Uyghur woman

The basic issue here is that in terms of genomic variation old admixture looks different from new admixture. Someone who is a first generation Eurasian, with a Chinese and European parent, may be about the same ancestral mix proportionally as a Uyghur. They would resemble a Uyghur on STRUCTURE and be placed within that cluster on a PCA chart (this is what happens in 23andMe). But, the Uyghur “Eastern” and “Western” genetic heritage has been reshuffled to a great extent by recombination over the past 1,000-2,000 years. In contrast, a first generation Eurasian will have huge swaths of their genome which are Eastern or Western on alternating strands (from their respective parents). In population genetic language a group of first generations hybrids would be exhibit a lot of linkage disequilibrium (LD). In a panmictic hybrid population LD will decay due to recombination, which breaks apart the distinctive allelic associations inherited from the parental populations.

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A positive rate of rate of change

A Cheaper Plan at Netflix Offers Films for Online Only:

Netflix said Monday that it was introducing a subscription plan for customers who want to watch movies only online, underscoring yet another step away from its roots in DVD rentals by mail.

The new plan offers unlimited access to Netflix’s library of streaming movies and TV shows for $8 a month. That is cheaper than virtually all of the company’s DVD plans.

I of course immediately downgraded; I haven’t received a physical DVD from Netflix since circa 2007 (it took me a year to return it because I forgot where I’d left it, and never watched it). But when I’m not feeling so well and can’t focus on anything cognitively challenging Netflix is very convenient. There are plenty of free alternatives on the net, but I’ll pay sub-$10 fees to save some time and headache.

But it does make me reflect on the rapid changes in the area of home entertainment since World War II. Video displaced 8 mm in the 1980s, but VCR’s themselves totally evaporated in the first half of the 2000s. Now the DVD format itself is being superseded, but the internet is replacing the hard copy mode of distribution in general for home film viewing. Netflix is already supposedly 20 percent of peak US traffic.

Also, I just realized that I don’t think I’ve been inside of a specialty “video store” since the early 2000s (most definitely from when I first subscribed to Netflix in late 2004). I have looked in the windows, and from what I can tell these stores are all-DVD format now, and it’s rather strange that I’ve never been inside of a “DVD store” even though I’ve passed so many of them over the years. Have you? Do they still rent video games as well?

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A synaesthetic mouse?

An amazing study just published in Cell starts out with fruit flies insensitive to pain and ends up with what looks very like a synaesthetic mouse. Penninger and colleagues were interested in the mechanisms of pain sensation and have been using the fruit fly as a model to investigate the underlying biological processes. Like any good geneticist faced with profound ignorance of how a process works, they began by screening for mutant flies that are insensitive to pain. Making use of a very powerful genetic resource developed in Vienna (a bank of fly lines expressing RNA interference constructs for every gene in the genome) they screened through all these genes to see which ones were required in neurons for flies to respond to pain. (In particular, pain caused by excessive heat).

Why should anyone care how a fly feels pain? Well, like practically everything else you can think of, the basic physiology and molecular biology of pain sensation is very highly conserved from flies to mammals. It starts with specialized proteins called TRP channels, which are ion channels that span the cell membrane and allow ions to pass across it in response to various stimuli. Some of these TRP channels respond specifically to painful stimuli, some even more specifically to painful heat, and these molecules are highly conserved. The hope was that by screening for other genes they would identify additional conserved elements of the pathway.

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