Archive for December, 2007

Watching out Bloggingheads.TV

By Razib Khan | December 20, 2007 4:37 am

Ross Douthat introduces The Table: Atlantic Voices in Conversation. I dig the head bob! Very professional.

CATEGORIZED UNDER: Blog

Xmas is not about Truth

By Razib Khan | December 19, 2007 6:06 pm

Ed, Greg & PZ have commented on the strange reaction of the president of the Southern Baptist Theological Seminary toward Richard Dawkins’ enthusiasm for Christmas traditions. So “why would an atheist want to sing Christmas carols?”
The same reason that the study and reading of literature has not been reduced to physics. We humans appreciate great stories, and we can conceive in our mind’s eye ideas which may not be true, but we enjoy the play of those ideas nonetheless. One does not have to be a Greek pagan to appreciate the beauty and power of the Iliad, and in fact for centuries pious Christians have been moved by the poems of Homer without acceding to the reality of its relgious vision. For them Homer was not about the Truth of the gods, but the Truth of human experience. We don’t need to appeal to a classical education though, anyone who reads a piece of moving fiction can be emotionally impacted, without entertaining that the narrative is real in a positivistic sense.

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CATEGORIZED UNDER: Culture

White skin does a body good (in certain climates)

By Razib Khan | December 19, 2007 2:58 pm

EVOLUTIONARY ADAPTATIONS: THE IMPACT OF LIGHTER SKIN:

It would take someone with dark skin of African or South Asian ancestry about 60 minutes at the same time of day to make the amount of vitamin D that a person of European ancestry would make in about 10 minutes, estimates Reinhold Vieth, one of Canada’s top vitamin D experts and a professor in the department of nutritional sciences at the University of Toronto.

You probably know of Vitamin D deficiency for rickets, but I think more common ailments might have a major fitness impact:

VDR ligands have also been shown to increase the activity of natural killer cells, and enhance the phagocytic activity of macrophages…Active vitamin D hormone also increases the production of cathelicidin, an antimicrobial peptide that is produced in macrophages triggered by bacteria, viruses, and fungi…Vitamin D deficiency tends to increase the risk of infections, such as influenza and tuberculosis. In a 1997 study, Ethiopian children with rickets were 13 times more likely to get pneumonia than children without rickets

CATEGORIZED UNDER: Science

Britney Spears' sister, Jamie Lynn, is pregnant

By Razib Khan | December 19, 2007 7:09 am

jlynn.jpgSo The Superficial is reporting that Jamie Lynn Spears is pregnant by her boyfriend Casey Aldridge. Jamie Lynn is Britney Spears’ younger sister, and at 16 she will be a “teen mother,” but not a stereotypical one. Jamie Lynn Spears has her own television show and seems to have her shit “together.” The stereotype is that the poor and those of lower SES are more likely to get pregnant as teens. That is statistically true:

Compared to teens from higher income families, poor and low-income teens are somewhat more likely to be sexually active and somewhat less likely to use contraceptives or to use contraception successfully. Poor and low-income adolescents make up 38 percent of all women ages 15 to 19; yet, they account for 73 percent of all pregnancies in that age group.

Nearly 60 percent of teens who become mothers are living in poverty at the time of the birth.

I recall reading a Naomi Wolf book years ago where she recounted that though her family income was lower-middle-class, sociologically her outlook was middle to upper-middle-class (i.e., the perpetual graduate school set). I think what you have with the Spears is the inversion, though wealthy because of their success in the entertainment industry they exhibit the ticks of those in lower social classes. I don’t need to repeat Britney Spears’ “adventures” of late. Here’s some possible highlights from the Spears family history:

Us has learned that Spears’ paternal grandmother, Emma Jean Spears, in June 1966 committed suicide at age 31. Britney’s grandmother, who suffered from depression, shot herself in the chest with a shotgun at the grave of her infant son who had died eight years earlier just three days after being born.

Emma Jean Spears left behind four other children, including Britney’s father, Jamie Spears, then an eighth grader. Two of Jamie Spears’ brothers ended up with criminal records and homeless.

The Spears’ wealth did not come via the typical bourgeois path of investment in education and skills which result in a low risk high yield career path. So it is no surprise that once Britney got free of her “handlers” she has behaved in a way that many middle class Americans find abhorrent. And anyone who has read Judith Rich Harris’ book The Nurture Assumption also knows one should be cautious of assuming that this sort of behavior and life outcomes are due simply to socialization or environmental inputs. Rather, a good proportion of personality and the sum of characteristics which shape the probability distribution of choices given a conventional range of options is contingent upon genetic variation.

CATEGORIZED UNDER: Genetics

Four Stone Hearth #30

By Razib Khan | December 19, 2007 2:01 am

Check out Four Stone Hearth #30.

CATEGORIZED UNDER: Blog

Maternal grandparents go the extra mile?

By Razib Khan | December 18, 2007 4:43 pm

Family Ties That Bind: Maternal Grandparents Are More Involved In The Lives Of Their Grandchildren:

For grandparents living within 19.5 miles (30 km) of their grandchildren, over 30% of the maternal grandmothers had contact daily or a few times a week. Around 25% of the maternal grandfathers had contact daily or a few times a week. In contrast, only around 15 % of the paternal grandmothers and little more than 15% of the paternal grandfathers would have contact daily or a few times a week.

The sample was Dutch, and the authors hypothesize that the reason that maternal, as opposed to paternal, grandparents go the extra mile is that they are wholly certain of their genetic relationship. In other words, motherhood is certain and fatherhood is theoretical (though this varies by society). This isn’t a new finding, and the results can be found in societies. It also manifests in the Grandmother Effect studies, maternal grandmothers quite often invest more than paternal grandmothers in their grandchildren.

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CATEGORIZED UNDER: Evolution

Adaptive acceleration

By Razib Khan | December 18, 2007 4:15 am

The acceleration story has finally cooled down a bit judging by my google news feed. That being said, I suggest you check out the comments threads on p-ter’s two posts, here & here. John Hawks and some of the other authors of the paper have been participating in the back and forth. The paper is finally on PNAS‘s site (Open Access), with the supplementary information. It is also important that you read this paper in concert with Global landscape of recent inferred Darwinian selection for Homo sapiens, which has a detailed explication of the methods and more specific data.

CATEGORIZED UNDER: Evolution

Pygmies & life history reviewed

By Razib Khan | December 17, 2007 3:22 am

Greg Laden has a pretty thorough critique of Life history trade-offs explain the evolution of human pygmies.

CATEGORIZED UNDER: Blog

Oekologie #12

By Razib Khan | December 17, 2007 12:16 am

Oekologie #12 at Behavioral Ecology Blog.

CATEGORIZED UNDER: Blog

Rocks

By Razib Khan | December 16, 2007 12:55 pm

For those of you who like it dead, The Accretionary Wedge #4.

CATEGORIZED UNDER: Science

Evolution for Engineers

By Razib Khan | December 15, 2007 11:50 pm

I received this email today:

Hi, I have a younger cousin who ran with a protestant fundamentalist crowd early in high school and as result started turning her nose at the notion of evolution, I thought she was a lost cause but now in her senior year she as mellowed (probably due to the mellowing of her crush on the fundie boy that drew her to this crowd in the first place) and I’d like to give her a book for Christmas that would relax whatever reflexive hang-ups she has acquired to studying evolution and biology. Since she’s planning on going into engineering and has a real interest in the subject I wanted to get her a popular science text that highlights the design and engineering aspects of evolutionary adaptations. I remember The Blind Watchmaker delving into this stuff but I don’t want any of Dawkins’s jabs at religion to rub her the wrong the way. Know any other book that might work, not something too high-level but something that more specifically focuses on engineering parallels than just discussing evolution. Thanks for any suggestions.

The intersection between not high-level and focusing on engineering kind of made me scratch my head a bit. I went with these three in the response: Adaptation and Natural Selection, The Selfish Gene and The Genetical Theory of Natural Selection. I know that the correspondent stipulated that the work not be high level, but I think you can get a lot out of The Genetical Theory of Natural Selection without following all the details of how R.A. Fisher derives his formalisms; much of the math is accessible to an advanced high school student. Do readers have better suggests with the constraints imposed above? I’m actually curious for myself in terms of what texts might be best in spreading the Adaptive News.
Note: It might actually be good for engineers to see how evolution is constrained by contingent conditions (e.g., phylogenetic or developmental constraint) in many cases.

CATEGORIZED UNDER: Evolution

Acceleration and Creationism

By Razib Khan | December 15, 2007 12:28 pm

Here is an article suggesting that Creationists should be scared of the accelerated human adaptation paper. At first, I would be skeptical, after all, this is microevolution, which Creationists ostensibly accept.1 But the reality is that anti-evolutionary thinking is pretty shallow, most Creationists barely know what they believe aside from the fact that they aren’t “descended from monkeys,” let alone the details of evolution (aside from canned talking points which they parrot with absolutely no understanding, e.g., “The second law of thermodynamics….”). I bring this up because a friend of mine who is an evangelical Christian student at Pepperdine University IMed me to ask about the acceleration paper. To be short about it his mind was blown away and he was really shocked by the implications and possibility that humans are evolving today at such a rapid rate. Though he’s a relatively bright individual he is probably about average in his knowledge of science as far as the typical evangelical goes (he has lately been shifting toward a less literalist interpretation of the Bible). My friend’s reaction suggests to me that though Creationists assert that they accept microevolution the model that they are promoting simply results in the inability of many evangelical Christians to comprehend that organisms change over time due to natural selection in the generality. If more Americans lived on farms and saw animal breeding in their day to day life this might not be an issue, but as it is these sorts of biological details have to be imbibed via books in our urban world. And if you reject the academic authorities, well you might never internalize the reality you never experience….
1 – I am one who thinks that the distinction between micro and macro evolution is one of semantic convenience and notation for the most part.

CATEGORIZED UNDER: Blog

Katz

By Razib Khan | December 14, 2007 2:35 pm

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CATEGORIZED UNDER: Blog

Menopause in chimps? Or not?

By Razib Khan | December 14, 2007 1:10 am

I’ve blogged about The Grandmother Hypothesis. Roughly, the question is why do women go through a “change” which rapidly shifts them from being able to become pregnant, though at sharply reduced rates by the time that menopause occurs, to a state of infertility where they may survive for up to three decades? Some argue that this is a peculiar human adaptation and that our social structures, where grandmothers may gain more in investing in their grandchildren than continuing to produce offspring in terms of long term reproductive fitness, are the cause. In contrast to women for males the pattern is one of gradual and consistent decline as the reproductive system is affected by the global breakdown of function characteristic of senescence. Now some data from chimps, Menopause in Chimps?:

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CATEGORIZED UNDER: Evolution

KITLG makes you white skinned?

By Razib Khan | December 13, 2007 3:14 pm

A few years ago, a new paper, SLC24A5, a putative cation exchanger, affects pigmentation in zebrafish and humans, made some waves. It used zebrafish to elucidate the genetics of a locus, SLC24A5, which is responsible for 1/3 of the between population difference between Europeans and Africans in skin color. In short, Europeans are fixed for a derived variant, and Africans and East Asians for an ancestral one. Additionally, SLC24A5 shows up in tests for very recent (last 10,000 years) selection, and is implicated in 1/3 of the skin color variation in South Asians. Today, a similar paper which focuses on KITLG, cis-Regulatory Changes in Kit Ligand Expression and Parallel Evolution of Pigmentation in Sticklebacks and Humans:

Here we use genetic crosses in sticklebacks to investigate the parallel origin of pigmentation changes in natural populations…In humans, Europeans and East Asians also share derived alleles at the KITLG locus. Strong signatures of selection map to regulatory regions surrounding the gene, and admixture mapping shows that the KITLG genomic region has a significant effect on human skin color. These experiments suggest that regulatory changes in Kitlg contribute to natural variation in vertebrate pigmentation, and that similar genetic mechanisms may underlie rapid evolutionary change in fish and humans.

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CATEGORIZED UNDER: Genetics

Life history & human evolution

By Razib Khan | December 12, 2007 2:53 pm

Two articles in PNAS caught my attention, Rapid dental development in a Middle Paleolithic Belgian Neanderthal & Life history trade-offs explain the evolution of human pygmies. Here are the abstracts:

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CATEGORIZED UNDER: Evolution

Kill the apostates!

By Razib Khan | December 12, 2007 4:52 am

In Britain there’s a story circulating about a young woman of Pakistani ethnicity who converted to Christianity and was persecuted by her family. Specifically:

Last week, it was reported that the daughter of a British imam was living under police protection, after receiving death threats from her family for having left Islam.

There’s more. Note that this is about converts to Christianity. This is a particular problem, secularism or private atheism are less likely to be the target of violence because it is not a defection to an alternative and vigorous rival faith. There have been other stories over the years about this problem among Muslims in the United Kingdom. Of course, the British media is prone toward exaggeration and bending the truth in the interests of a wild story. But, these data are pretty well attested:

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CATEGORIZED UNDER: Religion

Ancient human population sizes

By Razib Khan | December 12, 2007 12:24 am

In light of the recent work on the acceleration of human evolution due to increased population size, this paper in Genetics, Inferring Human Population Sizes, Divergence Times and Rates of Gene Flow From Mitochondrial, X and Y Chromosome Resequencing Data:

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CATEGORIZED UNDER: Genetics

Mendel's Garden #21

By Razib Khan | December 11, 2007 1:58 am

Mendel’s Garden #21.

CATEGORIZED UNDER: Blog

Accelerated adaptive human evolution news

By Razib Khan | December 10, 2007 5:15 pm

This google news query should get you to popular press articles. I’ll start putting links to blogs when more come in.
Blogs: One of the lead authors, John Hawks, promises lots of commentary this week. Greg Laden has some questions regarding the demographic assumptions. Steve Sailer with a round-up and Linda Seebach offers the bigger picture. p-ter offers some pointed criticisms. John Hawks does some rapid response. Eric Wang and Henry Harpending offer specific comments. John Hawks’ summary for lay people (long). Shoshin goes over the theory too. Popgen Ramblings says simulation is important. p-ter offers more “notes.” Popgen Ramblings has another post up in response to a John Hawks comment..
Quotes below from news articles….

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CATEGORIZED UNDER: Blog
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