The Messiah will be on In Our Time to discuss the evolutionary origins of altruism. They are pretty good about getting the archive up in a day or so. Interesting that they illustrate the idea with Mr. a priori Kant, or am I being pretentious and misunderstanding Kant? I simply suspect that Dawkins will argue and elucidate an evolutionarily beneficial situationalism.
Matthew 10:34 “Think not that I am come to send peace on earth: I came not to send peace, but a sword.”

Gene-culture coevolution is a topic of interest for me. Consider adult milk digestion. It’s weird, and seems like a new adaptation. The lactase gene has been under such strong selection that it is often used (or the region around it) as a control to test whether new methods for detecting selection actually work where we think they should work.
Here are a few maps I reworked from this paper:
The area where cattle genes which produce milk are diverse is relevant because that is the region where milk producing cattle have likely been resident the longest. The logic is similar to why Africans are assumed to be the source population for other humans: their genetic material exhibits the extant variation of an ancient population which has been resident for a long enough period to build up mutations. Note the close correspondence!
Now, recently I stumbled onto to this old paper about differences in lactose tolerance in north and south Indians. The range given seems to be about 75% lactose tolerance in northern India vs. 35% in southern India. What’s going on here? Some make a phylogenetic argument: lactose tolerance is a signature of Aryan immigration. The problem with this argument is that South Asians are fundamentally closer to each other than they are to outside populations, and the vast majority of ancestry seems to derive from around the Ice Age or before. Though some exogenous genetic material can be found in northern Indians which is derived from populations to the north & west, the extent does not predict the level of lactose tolerance that we see. If one assumes that Indians were not lactose tolerant originally and it was introduced than south Indians would exhibit at least 35% admixture, while north Indians would be 75% exogenous (assuming really simple genetic models obviously). This isn’t warranted by any of the other data on other loci. Additionally, the recent genomic work on the lactase genes suggests the unity of the origin of Eurasian lactase persistence. In other words, the genetic strategy in Eurasia, the T allele on LCT, appeared once, and spread (in Africa there seem to be other strategies). But if other genes don’t support massive admixture between various Eurasian populations…what happened? Gene flow, and a selective sweep of a favored allele! India has many cows, and dairy is part of the diet, but this is most prevalent in the northwest where lactose tolerance has the highest penetration. When the T allele entered India its fitness was very high in the north, and less so in the south. So it rose to high frequency driven by positive selection just as it has in many other cultures.

Not a genetic story, but amusing (well, I thought so), this report from today’s London Times:

A Muslim who killed a swan [a protected species] during Ramadan has been given a two-month prison sentence. Shamsu Miah, 52, killed the mute swan at a boating pond in Llandudno, North Wales, on September 25. When challenged by police he said: “I am a Muslim. I am fasting. I needed to eat.” Llandudno magistrates were told that Miah, from the town, had white feathers stuck in his beard and blood on his shirt.

Which raises the questions: did he actually eat it raw? And was this halal?

Richard Dawkins will be on In Our Time to discuss the evolutionary origins of altruism. They are pretty good about getting the archive up in a day or so. Interesting that they illustrate the idea with Mr. a priori Kant, or am I being pretentious and misunderstanding Kant? I simply suspect that Dawkins will argue and elucidate an evolutionarily beneficial situationalism.

Drunk thugz? Apparently Asians have the market on violin playing in Europe too….

Nick Anthis, he of the fake British accent, has a follow up post on “ethical stem cells.”

David points out that they are talking about Mormons in The Corner today relating to Mitt Romney.
Jonah thinks that the Mormon thing might help
An evangelical who is married to a Mormon thinks that it isn’t a big issue
Anti-Mormon readers weigh in
A Mormon comments on the anti-Mormons
Mormonism is a falsifiable cult
Another Mormon emailer
I posted something very long on Mormons last year. I am skeptical that Romney can make it past the Republican primaries, because ceteris paribus he just can’t match up. I can’t believe that the Republicans can’t produce a convential Christian with Romney’s policy stands and competence. I won’t review the mismash with various issues relating to Mormonism, the main problem is that the religion was invented in the light of history, and its theology is very bizarre to most Christians.

Biology and anthropology carnivals. Have a good Thanksgiving!

You know the names of some neurotransmitters: dopamine, serotonin, norepinephrine. Glutamate is the major excitatory neurotransmitter and GABA is the major inhibitory one, right?. All neurotransmitters function in a similar way to communicate between two neurons. The pre-synaptic neuron sends messages in the form of neurotransmitter for the post-synaptic neuron to receive at neurotransmitter receptors.

Let’s focus on the pre-synaptic side for a minute. Neurotransmitters aren’t released one at a time. They are released in bulk, thousands at once. This is achieved by packaging the neurotransmitters up into a little sac in the pre-synaptic termincal called a synaptic vesicle. You can see hundreds of these in electron micrographs of synapse.

When the pre-synaptic neuron gets the cue to dump neurotransmitters, the vesicle, which has a lipid bilayer membrane just like the cell’s membrane, fuses with the cell membrane through an elaborate protein winching mechanism. This releases the entire vesicle contents into the synapse at once. This process isn’t entirely understood, but many of the major proteins that interact between the cell membrane and the vesicle membrane are known. So a group recently did a ton of mass spec and quantitative measurements to determine more precisely the protein content of a given synaptic vesicle and produces a model vesicle. I think it is just lovely:

They found that a surpising amount of the membrane space on a vesicle was ‘dedicated’ meaning that it either contained a trans-membrane protein or certain lipid molecules that are unlikely to flow around very much within the membrane. Here is one of my favorite passages:

A picture is emerging in which the membrane resembles a cobblestone pavement, with the proteins organized in patches that are surrouneded by lipid rims, rather than icebergs floating in a sea of lipids.

In the HapMap database are genotypes for over 3 million single nucleotide polymorphisms (SNPs) in 270 people– 90 people of Western European descent, 90 people from Nigeria, 45 from Japan, and 45 from China. This is a spectacular resource for all sorts of population genetic, medical, and evolutionary studies. Yet SNPs aren’t the only way people vary– duplications and deletions of genome material are also important (as are other changes). Now, for those same 270 people who make up the HapMap, a catalogue of the duplications and deletions (or really, all variation in copy number) segregating in the populations has been generated. This is reported in the most recent issue of Nature.

Of note, they find that the actual quantity of DNA affected by these copy number variants covers a full 12% (!) of the genome. That is a huge amount of variation (we’re all genetically 99% the same, right?), but is it functional? The authors note that copy number changes tend to stay away from known genes, but there are a number of examples of functional copy number changes, including ones that influence succeptibility to the HIV virus or glomulonephritis (whatever that is). I expect these sorts of variants to be very important in complex traits– they provide the raw material for subtle changes in regulatory networks, which will then affect subtle phenotypic changes.

Another interesting story is that of the MAPT locus. This locus is marked by an inversion on one haplotype that has been under selection in Europeans. The two haplotypes at the locus are extremely diverged, which to some suggest another introgression event from Neandertals. An inversion that remains polymorphic in a population is interesting, because individuals heterozygous for the inversion are expected to have reduced fertility (recombination in the area of the inversion leads to imbalanced chromosomes). The apparent positive selection on this locus is, in that context, a bit puzzling. I’m not sure the authors realize this, but they might have solved this problem–if the duplication is the cause of the increased fitness, it would conteract the deleterious effects of the inversion. Unfortunately, there’s not a lot of detail here, and it’s not even clear that the duplication is on the positively selected haplotype.

Finally, there seem be some copy number variants that are have very different frequencies in the populations examined, suggesting possible differential selection. Among them is the variant known to decrease succeptibility to HIV and another known to play a role in androgen metabolism.

So the HapMap cell lines pay off once again and the human genetics community reaps the rewards; it’s hard to believe that a number of people were against the construction of this resource.