Check out these two posts on the extrasolar planet. I remember reading as a kid a short Poul Anderson essay on “how to design a habitable planet” (for a science fiction story).

Of late I have been leaving my laptop behind and taking my books to coffee shops to get my reading done. The reason is simple, I have a compulsive tendency to look up data on references made within the text of any book. For example, if there is an offhand reference to the Dual Monarchy of Austria-Hungary, I have to look it up so I know more about it. I probably do this sort of thing around two times per page, and the discontinuity it generates is a real bother. When reading material on the internet, in particular Wikipedia entries, I have to make an effort not to click illuminating links precisely because I know that within a few minutes I’ll have become snared in a whole new tangle of facts. I assume I’m not the only one….

When we talk about genetic variation between populations, most of the time we’re referring to SNPs or other “simple” polymorphisms, mostly because that’s what we have data on. Detailed population genetics studies of copy number variants are just starting to appear; this paper is one of them. It’s an anlysis of the frequency of a deletion of the gene APOBEC3B, involved in immunity to retroviral infection. As you can see in the map below, the gene is present in most people of European and African descent, but is missing in a significant fraction of Asian and Native American populations. Nothing revolutionary here, but expect more studies of this sort in the future.

ADDENDUM: I hasten to add, lest RPM read this post, that when I say these studies are starting to appear, I’m speaking about these sorts of studies in humans. In Drosophila, large deletions and inversions are the classic genetic polymorphisms used in population genetic analyses (due to their easy visibility in polytene chromosomes).

Erick Trinkaus has a new article in PNAS, European early modern humans and the fate of the Neandertals:

A consideration of the morphological aspects of the earliest modern humans in Europe (more than ~33,000 B.P.) and the subsequent Gravettian human remains indicates that they possess an anatomical pattern congruent with the autapomorphic (derived) morphology of the earliest (Middle Paleolithic) African modern humans. However, they exhibit a variable suite of features that are either distinctive Neandertal traits and/or plesiomorphic (ancestral) aspects that had been lost among the African Middle Paleolithic modern humans…The ubiquitous and variable presence of these morphological features in the European earlier modern human samples can only be parsimoniously explained as a product of modest levels of assimilation of Neandertals into early modern human populations as the latter dispersed across Europe. This interpretation is in agreement with current analyses of recent and past human molecular data.

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A new paper in Evolution, THE LOCUS OF EVOLUTION: EVO DEVO AND THE GENETICS OF ADAPTATION.

An important tenet of evolutionary developmental biology (“evo devo”) is that adaptive mutations affecting morphology are more likely to occur in the cis-regulatory regions than in the protein-coding regions of genes…Neither the theoretical arguments nor the data from nature, then, support the claim for a predominance of cis-regulatory mutations in evolution. Although this claim may be true, it is at best premature. Adaptation and speciation probably proceed through a combination of cis-regulatory and structural mutations, with a substantial contribution of the latter.

One of the coauthors, Jerry Coyne, has taken aim at evo devo before.

The April 16th issue of The New Yorker had an article by John Colapinto, The puzzling language of an Amazon tribe. It’s in print, so I can’t post it, but the short of it is that the tribe might lack recursion, a hammer blow to Chomskyan universal grammar. Overall the tribe seems to have a rather attenuated tendency toward engaging in abstract thought, and has been incredibly immune to any attempts by Christian missionaries to convert them. At some point in the piece the author notes that occasionally someone will ask a Christian if they’ve ever met this Jesus Christ that they keep talking of, and when they’re told that he died 2,000 years ago all interest disappears. Below, I argued that humans have psychological propensities which bias them toward being religious. If the research about these Amazonians pans out I think you have here a group which is totally insulated by their culture from the attractions of religion because they lack some of the necessary psychological propensities (I suspect, and the article pretty much claims, that those propensities can be developed by tribal members who are raised outside of the group, but that culture constrains cognition in this case). Now, I’ve said that though I’m not religious myself and kind of find the whole behavioral tendency kind of alien and strange, I think that we’ll have to turn humans into autistics for them to truly be “rid of” religion. The Amazonians are not autistic, but, in some ways they are pretty strange, and I don’t know if we want most people to live like them if that’s the price for being grounded in the empirical present instead of delusions of the supernatural.
Update: Here’s a list of unique traits for this people.

I have a long post on my other blog about the reality that in I believe religion must be analyzed at different levels of organization. On the one hand, religious beliefs must be “fit” in the context of what representations our minds can accept, find plausible and memorable. But higher up the chain of organization religion can play a utilitarian role in demarcating and differentiating social groups. The relationship between these two levels is fleshed out in more detail in the post. Below the fold I’ve placed a list of my main posts on religion over the past year….

The nature of religion and Breaking the Spell
Modes of religion
Who Dan Dennett think he be foolin’?
An evolutionary anthropology of religion
God lives, deal with it!
Belief & belief in belief
Logical consistency is irreligious
God & morality
Are people naturally religious? Yes….
The round-eyed Buddha
Nerds are nuts
Atheism, Heresy and Hesychasm
The God Delusion – Amongst the unbelievers
Innate atheism & variation across societies
“Hard-wired” for God
Buddhism, a religion or not?
Why do people believe in God?
Is religion an adaptation?
Theological incorrectness – when people behave how they shouldn’t….sort of
The gods of the cognitive scientists

I have said many times that phrases like “moderate Muslim” must be normed to the distribution of attitudes amongst Muslims. To be in the moderate/median central region of the distribution of Islamic beliefs is not the same as being in the moderate/median central region of the distribution of Christian beliefs. I have made it pretty obvious that over the years I have come to the conclusion that selection, so to speak, will probably eventually shift the Muslim median religio-phenotype closer to the Christian one. That being said, Ali Eteraz pointed me to an interesting site, Apostasy and Islam – 100+ Notable Islamic Voices affirming the Freedom of Faith. On the one hand, it is a good thing that there notable Muslims who agree that it is not acceptable that those who disavow the Islamic religion are subject to the death penalty, at least de jure, in much of world. But, the fact that 100 scholars need to be firm and vocal on this issue tells you about the “state of Islam”.

An AEI event, Darwinism & Conservatism, May 3rd in Washington DC. John Derbyshire will be there.

Speaking of human brain evolution, PLoS Genetics gives us this, “Conservation of Regional Gene Expression in Mouse and Human Brain”:

Here we compare gene expression profiles of human motor cortex, caudate nucleus, and cerebellum to one another and identify genes that are more highly expressed in one region relative to another. We separately perform identical analysis on corresponding brain regions from mice. Within each species, we find that the different brain regions have distinctly different expression profiles. Contrasting between the two species shows that regionally enriched genes in one species are generally regionally enriched genes in the other species. Thus, even when considering thousands of genes, the expression ratios in two regions from one species are significantly correlated with expression ratios in the other species. Finally, genes whose expression is higher in one area of the brain relative to the other areas, in other words genes with patterned expression, tend to have greater conservation of nucleotide sequence than more widely expressed genes. Together these observations suggest that region-specific genes have been conserved in the mammalian brain at both the sequence and gene expression levels. Given the general similarity between patterns of gene expression in healthy human and mouse brains, we believe it is reasonable to expect a high degree of concordance between microarray phenotypes of human neurodegenerative diseases and their mouse models. Finally, these data on very divergent species provide context for studies in more closely related species that address questions such as the origins of cognitive differences.

Long story short– the human brain is not some freak/miracle; studying mouse brains will be worthwhile as a tool for understanding human brains in general. This is also a step towards understanding what exactly it is that makes a human brain so different genetically from a mouse brain– which developmental pathways have been altered, which parts of the brain most diverged? Previous studies of gene expression evolution have treated the “brain” as a single organ; now we can get in at its finer details.