{"id":28040,"date":"2015-06-13T13:05:33","date_gmt":"2015-06-13T12:05:33","guid":{"rendered":"http:\/\/theskepticalzone.com\/wp\/?p=28040"},"modified":"2015-06-13T13:05:33","modified_gmt":"2015-06-13T12:05:33","slug":"alzheimers-and-evolution","status":"publish","type":"post","link":"http:\/\/theskepticalzone.com\/wp\/alzheimers-and-evolution\/","title":{"rendered":"Alzheimer’s and Evolution"},"content":{"rendered":"

I have to say, while the UD “newsdesk” is terrible source for comment on scientific news, the links themselves are often interesting.\u00a0 Today, the UD “newsdesk” reports <\/a>on a pretty interesting study, reported in Nature, here<\/a>, and a preprint of which seems to be open access here<\/a><\/p>\n

It’s been apparent for a while from Genome-Wide Association Studies (GWAS) that “risk” alleles for various mental disorders, despite being statistically significant, have extremely small effect sizes.\u00a0 In other words, while the studies show that many mental disorders are indeed associated with specific alleles (and we already know that many are highly heritable, including schizophrenia, ADHD and Alzheimer’s), there aren’t just a few rogue alleles of large effect (well, there are, but they are far rarer than these disorders), but instead, a whole cocktail of alleles with very slightly raised Odds Ratios for certain disorders (and some are shared between multiple disorders).\u00a0 This means that the vast majority of people carrying these “risk alleles” are perfectly fine. That would help explain why they have not been weeded out by selection.<\/p>\n

<\/p>\n

But the interesting thing about this article is that it provides evidence that some have been positively selected for <\/em>– that they confer an advantage.\u00a0 Moreoever, they are alleles of genes implicated in brain function.<\/p>\n

We’ve known for a while that the “E4” variant of ApoE (carried by 1 in 7 of us) is a risk factor for Alzheimer’s<\/a>, and that it is also associated with enhanced cognitive performance early in life<\/a>.\u00a0 So it’s really interesting to see an actual systematic study of the evolutionary history of other genes implicated in brain function in general, and their downsides.<\/p>\n

And, Denyse: it’s only “Darwinbabble” if you don’t speak it.<\/p>\n","protected":false},"excerpt":{"rendered":"

I have to say, while the UD “newsdesk” is terrible source for comment on scientific news, the links themselves are often interesting.\u00a0 Today, the UD “newsdesk” reports on a pretty interesting study, reported in Nature, here, and a preprint of … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":444,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[47,23],"tags":[],"class_list":["post-28040","post","type-post","status-publish","format-standard","hentry","category-life-sciences","category-mind-and-brain"],"_links":{"self":[{"href":"http:\/\/theskepticalzone.com\/wp\/wp-json\/wp\/v2\/posts\/28040","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/theskepticalzone.com\/wp\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/theskepticalzone.com\/wp\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/theskepticalzone.com\/wp\/wp-json\/wp\/v2\/users\/444"}],"replies":[{"embeddable":true,"href":"http:\/\/theskepticalzone.com\/wp\/wp-json\/wp\/v2\/comments?post=28040"}],"version-history":[{"count":0,"href":"http:\/\/theskepticalzone.com\/wp\/wp-json\/wp\/v2\/posts\/28040\/revisions"}],"wp:attachment":[{"href":"http:\/\/theskepticalzone.com\/wp\/wp-json\/wp\/v2\/media?parent=28040"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/theskepticalzone.com\/wp\/wp-json\/wp\/v2\/categories?post=28040"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/theskepticalzone.com\/wp\/wp-json\/wp\/v2\/tags?post=28040"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}