Interesting article suggesting that the HLA variants associated with CD may have role in resistance to epidemic-like diseases. This might explain why the trait persists despite it apparent harmful effects to grain-eaters. The ability to resist epidemic diseases was more important to survival.
Hawks, too, has been digging into the archaic genomes, and his team has already discovered that Neanderthals and Denisovans lack certain forms of genes that may help modern humans to fend off epidemic diseases, such as measles. This is hardly surprising: the low population density of hunter-gatherers meant that epidemics were unlikely, so they probably would not have benefited from these immune genes.
But Hawks's team is now using the find to test whether the defensive genes are linked to autoimmune diseases. In September, Hawks and his colleague Aaron Sams are scheduled to present data at a meeting of the European Society for the Study of Human Evolution in Leipzig, Germany, showing that the Denisovans lacked nearly all of the gene variants linked to coeliac disease, a gut autoimmune disorder present in modern humans. Hawks suspects that the variants may actually be in the same genes that are linked to epidemic resistance — if they are, further study could reveal how recently such autoimmune diseases arose in humans.
Rosie
Our greatest weakness lies in giving up. The most certain way to succeed is always to try just one more time………Thomas Edison
Very interesting article. And, of course, the suggested connection between celiac disease, and pathogens that tend to cause epidemics, is supported by the fact that the most disruptive symptom of celiac disease appears to be due to the production of zonulin, (which opens the tight junctions in the small intestinal epithelia). Zonulin was initially discovered over 10 years ago, as the target of zonula occludens toxin, which is secreted by the pathogen that causes cholera in humans. Interestingly, zonulin is also implicated in type 1 diabetes.
Presumably, that would suggest that the genes that predispose to MC might also fall into this category, implying that we should have enhanced epidemic resistance. Or am I looking at this wrong?
Thanks for the link.
Tex
It is suspected that some of the hardest material known to science can be found in the skulls of GI specialists who insist that diet has nothing to do with the treatment of microscopic colitis.
Rosie, thanks for the awesome article - I just shouted HA! very loud and alarmed my husband, because I have long suspected that that had to be the case. The quirk isn't in the genes - it's in the diet. Gluten sensitivity and its associated genes have been *adaptive* for dwillions of years. And then came grain agriculture.
FWIW, I was betting on chicken pox, not measles ;) Or maybe typhoid, along with cholera? Oddly, measles was the one childhood disease I had no immunity to, when I was re-tested in order to volunteer in a local pre-school. (You cannot imagine how hard I had to fight to get a rubeola vaccine - *everyone* kept correcting my pronunciation to rubella, which I had and am still immune to).
Gluten sensitivity is so widespread, and there are so many gene variants, it's the only plausible explanation... it actually belongs there. It's so very different from other gene 'quirks' in its distribution and effects; unlike sickle-cell, its incidence in the population has not reduced over time, as the relative advantage (at least here in the States) of having a single gene has disappeared with the threat of malaria...
Tex, I do think this might apply to non-celiac GS gene variants as well - I think it's even possible that someone with a particular sort of zonulin response (celiac or non-) would have responded differently (pre-grain agriculture) to cholera pathogen exposure. Maybe faster immune response is mounted if the gut gets into the act in a particular way? I know I'm speaking speculatively and non-scientifically, but I am excited that someone might start thinking about this in a novel way.
As soon as I saw that quote from the article, I knew that your eyes were going to light up like a pinball machine as soon as you read it.
Love,
Tex
It is suspected that some of the hardest material known to science can be found in the skulls of GI specialists who insist that diet has nothing to do with the treatment of microscopic colitis.
Presumably, that would suggest that the genes that predispose to MC might also fall into this category, implying that we should have enhanced epidemic resistance. Or am I looking at this wrong?
Tex, another thought occurred to me, that the non-celiac gluten sensitivity genes may be related not only to protection against epidemic diseases, but also to parasitic infections. The fact that infection with some types of intestinal parasites resolves the MC symptoms brought that to mind. These infections are a huge source of debility and mortality. And of course the more dense the population, the more water, soil and food contamination with parasites.
Rosie
Our greatest weakness lies in giving up. The most certain way to succeed is always to try just one more time………Thomas Edison
Sara, you and I remember them as the hard measles and the German measles. Calling rubella "German measles" is probably politically incorrect these days, lol. But the hard measles were very scary. One of my son's caretakers had them when she was a child and had to lie in a dark room for weeks to protect her eyes. Her eyes were fine, but she came out of them mostly deaf.
Marliss Bombardier
Dum spiro, spero -- While I breathe, I hope
Psoriasis - the dark ages
Hashimoto's Thyroiditis - Dec 2001
Collagenous Colitis - Sept 2010
Granuloma Annulare - June 2011
That definitely makes sense. I think I read somewhere that parasites and viruses can also trigger the production of zonulin.
Thank you for your insight.
Tex
It is suspected that some of the hardest material known to science can be found in the skulls of GI specialists who insist that diet has nothing to do with the treatment of microscopic colitis.
Marliss, as I recall, I was pretty sick with rubella (all the childhood diseases hit me hard and more or less bounced off my brother) - but it's nothing like the 'hard' measles. I am amazed I showed no immunity to it, when tested years later. I would think I'd have had them as a kid, and/or been vaccinated. Or maybe it was one of those immunities that wore off (in which case, the vax I had 10ish years ago may also have worn off...)
