A quick RSS note….

By Razib Khan | January 21, 2011 3:49 pm

Posts within the RSS feed will now be truncated. Since I occasionally write longer pieces, it is likely you’ll now have to “click through” to read the full post. If the ending of a post mystifies you, there is a good chance that it’s due to truncation, and not my being on some medications.

Finally, I feel guilty putting this post up without a great deal of content, so I’ll throw a thought out there triggered by discussion below on phenotypes in the Middle East: how many alleles which code for particular traits arose in the genetic background of population A only to move to fixation in population B? Lactase persistence in Europe may be a classic case of this, originating in Central Eurasian populations and later spreading to the Northwest European fringe, where the favored variant rose to near fixation. Here’s another possibility: the allele which codes for blue eyes in West Eurasian populations may have arisen outside of Europe, and moved into Europe through gene flow, and then been driven to fixation in the new environment. Often when people see someone with light eyes who is not European the presupposition is there has been European admixture, but it may be that a low proportion of individuals with the light eye variant around HERC-OCA2 has been the norm in Western Eurasia outside of Europe for a long time. Only in the European population did selection, or perhaps drift through population bottlenecks, recently drive the variant to near fixation around the Baltic. Anyway, I think that’s a plausible model,though someone who has looked at the haplotype in detail could no doubt disabuse me of the notion. I am inspired here by the ‘speed up’ model of human evolution, where large populations result in a greater mutational background from which natural selection can draw. Presumably with agriculture Middle Eastern populations exploded rather rapidly ~10,000 years ago vis-a-vis other groups in Western Eurasia. I now believe that a substantial proportion of the ancestry of modern Europeans and South Asians derives from a demographic expansion rooted in the Middle East (in combination with native substrate). Many of the traits diagnostic to Europeans and South Asians, and genetic alleles diagnostic to both groups, may then drive from the Middle Eastern newcomers, and not be due to deep local ancestry. This may be what occurred with R1b1b2.

Image Credit: George Baird.

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  • Markk

    A question regarding RSS reading. When I read your post in Google reader is it counted by your side as a reader? Or do I actually need to click through to be counted for you? Google Reader (what I use) knows that I read the article, but does Discovery blog site?

    I would feel bad at not being counted in the sense that this distorts things and loses you the pittance that visits might pay, but on the other hand I have perhaps 40 or 50 sites I read through Google reader – I can scan through like nothing skipping most. I would have perhaps 10 otherwise.

    By the way on a meta-topic. Is there some regional use of the word Baby as an insult? I read your post and replies and your reply and even though I am from the heart of the U.S. I felt like I was lost, the usage just seemed fine to me and I didn’t get the nuance. I mean it does not come across that way here, and I asked several people, and though we could see how it could be off if spoken in a nasty tone of voice, none of them seemed to get it either. English, our own foreign language, I guess.

  • Matt

    Would it be possible to do a full feed with ads in it instead? Also, it’d be nice if there was some “read the rest of this post on Gene Expression” rather than the story just cutting

  • Casey

    I guess I don’t mind the truncation — but it’s starting to really bug me that everything on Discover ends up in the feed at least twice.

  • http://blogs.discovermagazine.com/gnxp Razib Khan

    markk, to my knowledge not clicking through doesn’t count. i don’t hold it against u ;-)

    no idea about regionalism, but that’s a VERY good point. there’s going to be a variation of responses for any given word/context/idiom. sometimes the variances converges upon zero, and sometimes it is uniform.

    matt, i don’t control the means of production to such details. though i know that the powers-that-be do read these threads (why else am i on such good behavior? :-)

  • http://blogs.discovermagazine.com/gnxp Razib Khan

    also, re: offense. a bangaldeshi twitter follower was very offended by my recent series on ancestry. he inferred i was ashamed of being bangladeshi and didn’t take pride in it. he asked around others their opinion of my posts who were bangladeshi, and they had the same impression.

    it’s true i don’t take pride in being bangladeshi, but that’s because i don’t put much truck in group identity pride. perhaps i’d use a different word. additionally, i’m american. i don’t have a bi-national self-conception. but i’m certainly not ashamed of being who i am. but i wasn’t going to explain why to the twitter follower, the cultural gap is pretty large, and i don’t have the time or inclination to explicate the nature of the chasm. my ultimate aim to correct the issue whereby south asians tend to emphasize ties to peoples to the west (and take pride in that ancestry because of racial inferiority complexes). i have ties to the east, and i’m not ashamed about it at all. my personal experience is that many bangladeshis, whose faces testify to eastern connections, tend not to acknowledge or “own” this aspect of their identity as they do more tenuous connections to persians or turks.

  • TheDude

    I’m skeptical that the allele for blue eyes arose outside of Europe, given that its frequency peaks in the Baltic, which is also the nexus for hair (and necessarily skin) depigmentation.

    What are the odds of different genes pertaining to the depigmentation of the soft parts, which just so happen to be coincidentally expressed, having exogenous origins?

  • http://blogs.discovermagazine.com/gnxp Razib Khan

    #6, did you bother to read my post? or are you a devotee of the commenters-with-zero-value-add club? no shit that’s a plausible null.

  • Nathan

    “Often when people see someone with light eyes who is not European the presupposition is there has been European admixture, but it may be that a low proportion of individuals with the light eye variant around HERC-OCA2 has been the norm in Western Eurasia outside of Europe for a long time.”

    When you speak of assumed European admixture, what time frame are you referring to?
    Do you also include Indo-Iranian conquests of the SubContinent in 2nd millenium BC emanating from the Eurassian Steppes? I don’t know if you consider the Pontic-Caspian Steppes partially European.

  • http://blogs.discovermagazine.com/gnxp Razib Khan

    within the purview. let’s say europe as we define it since 1750, atlantic to urals to black sea to mediterreanean. 10,000 year BP to now.

  • Matt

    Your RSS feeds have always been extremely truncated for me – like half a sentence per post. This post, for example, showed up in Google Reader as: “Posts within the RSS feed will now be truncated. Since I occasionally …”

    That’s it. Am I doing something wrong?

  • http://pthree.org Aaron Toponce

    Truncated RSS feeds means unsubscriptions. I won’t click through. That’s the whole reason I’m using an RSS aggregator to begin with. Good luck.

  • http://blogs.discovermagazine.com/gnxp Razib Khan

    matt, your settings must have been doing something.

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Gene Expression

This blog is about evolution, genetics, genomics and their interstices. Please beware that comments are aggressively moderated. Uncivil or churlish comments will likely get you banned immediately, so make any contribution count!

About Razib Khan

I have degrees in biology and biochemistry, a passion for genetics, history, and philosophy, and shrimp is my favorite food. In relation to nationality I'm a American Northwesterner, in politics I'm a reactionary, and as for religion I have none (I'm an atheist). If you want to know more, see the links at http://www.razib.com

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