ALDaily points to this excellent article on the world’s top origami artists. This guy has a hell of a bio:

Lang kept folding while earning a master’s in electrical engineering at Stanford and a Ph.D. in applied physics at Caltech. As he worked on his dissertation—“Semiconductor Lasers: New Geometries and Spectral Properties”—he designed an origami hermit crab, a mouse in a mousetrap, an ant, a skunk, and more than fifty other pieces. They were dense and crisp and precise but also full of character: his mouse conveys something fundamentally mouse-ish, his ant has an essential ant-ness. His insects were especially beautiful. While in Germany for postdoctoral work, he and Diane were taken with Black Forest cuckoo clocks; the carved casings, pinecone-shaped weights, pendulums, and pop-out birds wouldn’t seem to be a natural for origami, but Lang thought otherwise. He started a job at NASA’s Jet Propulsion Laboratory, in Pasadena, in 1988, shortly after he had finished folding a life-sized cuckoo clock. It had taken him three months to design, and six hours to fold, and it made Lang a sensation in the origami world.

 

John Emerson has a long post about the relationship between irrationality and the emergence of new cultural forms. Worth reading. The other day I had a thought: many cultural traits are basically hitch-hiking along. Consider circumcision and the ban against pork consumption for Muslims, in places like Indonesia when tribes convert to Islam they abandon their pigs and circumcision becomes the norm. Why? People have been inventing strange functional rationales for these customs for decades. It seems likely that these practices have a role as ingroup vs. outgroup markers, that is, they’re convenient shibboleths. Food taboos of course impose segregation between different groups if they can’t eat together without transgressing their norms (e.g., Muslims eating at a Chinese house often have issues because of the ubiquity of pork). That being said, an interesting model for the “selection” of shibboleths is that the group in which cultural form or religion x arose tend to serve as a model, and so all sorts of peculiar customs spread outward. For Islam, circumcision and the non-consumption of pork would qualify (circumcision is actually not even a religious sacrament in Islam as it is in Judaism, but simply a custom which has become accepted through consensus as defining a Muslim male). The spread of Roman-Christian culture in Europe had the same effect, Romanitas entailed the spread and adoption of customs and traditions which were not central to the civilizing aspect of literate Mediterranean culture.

Hobolth A, Christensen OF, Mailund T, Schierup MH (2007) Genomic Relationships and Speciation Times of Human, Chimpanzee, and Gorilla Inferred from a Coalescent Hidden Markov Model. PLoS Genet 3(2): e7

They estimate 4.1 million years ago. It’s open access so no excerpts needed.

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According to the editors of Nature.

[W]hat has been universally deemed as unacceptable is the pursuit of human reproductive cloning – or the production of what some have called a delayed identical twin. Here, the two issues that have dominated the discussion have been dignity and safety. There is a consensus that dignity is not undermined if a human offspring is valued in its own right and not merely as a means to an end. But there is no consensus that we will eventually know enough about cloning for the risks of creating human clones to be so small as to be ethically acceptable.

The debate may seem to have been pre-empted by prompt prohibition. But as the science of epigenetics and of development inevitably progresses, those for whom cloning is the only means to bypass sterility or genetic disease, say, will increasingly demand its use. Unless there is some unknown fundamental biological obstacle, and given wholly positive ethical motivations, human reproductive cloning is an eventual certainty.

The current issue of Cell is dedicated to the rapidly changing field of epigenetics, loosely defined at the ensemble of chromatin and DNA modifications that structure the genome and control gene expression. The only review I’ve worked my way through yet is this one: Timescales of Genetic and Epigenetic Inheritance.

According to classical evolutionary theory, phenotypic variation originates from random mutations that are independent of selective pressure. However, recent findings suggest that organisms have evolved mechanisms to influence the timing or genomic location of heritable variability. Hypervariable contingency loci and epigenetic switches increase the variability of specific phenotypes; error-prone DNA replicases produce bursts of variability in times of stress. Interestingly, these mechanisms seem to tune the variability of a given phenotype to match the variability of the acting selective pressure. Although these observations do not undermine Darwin’s theory, they suggest that selection and variability are less independent than once thought.

The authors limit themselves largely to bacteria and yeast, but they document a great deal of evidence that parameters like the mutation rate change in response to external stimuli, perhaps in almost a “directed” fashion. Some work in primates has shown a correlation between the amount of mutation raining down on a population and the amount of beneficial mutations that arise. Could “directed” mutagenesis be an explanation for this?

The main points from the paper are summarized in the figure below; essentially, epigenetic inheritance is a way for a population to respond to environmental changes that occur on time scales shorter than those needed for genetic evolution.

Economists Wacziarg (Stanford) and Spolaore (Tufts) are using Cavalli-Sforza’s genetic distance data. They find that countries that are genetically different from the rest of humanity tend to be poorer, even after controlling for lots of popular variables (like geography and colonial experience, two recent favorites). Their explanation: It’s easier to get ideas from people who are similar–a contrast with much of the trade literature, where it’s easier to get gains from trade from people who are dissimilar.

As Google Scholar shows, W&S have drawn some attention. Along related lines, Bill Easterly and his coauthors remind us that the countries that were more innovative in 1000 BC tend to be richer today–so not much is new under the sun.

Of course, W&S remind us that it’s essentially impossible to disentangle genetic versus cultural stories when looking at nation-level data–and they note that their genetic measures are based on neutral markers, so it’s “different,” not “worse.”

By contrast, one way to interpret Easterly’s result is mere path persistence: A multiple-equilibrium story where you get it right once through sheer luck, and afterwards you’re likely to stay lucky forever. Difficult to disprove–maybe it’s a fair coin, and the West and East Asia just flipped Heads…

Genes, culture, luck: All three stories deserve some attention over the next few years. Two big problems: Measuring culture and luck. Genetic differences, those we’ll be able to measure, with greater precision every year. But that’s almost as much a curse as a blessing, since it’d be extremely valuable to be able to disentangle these hypotheses.

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This week’s In Our Time is about William Wilberforce. Unfortunately, many on this side of the pond don’t recognize the name. They should.

Eurekalert:

“What we found was that, in certain cases, edited versions of these microRNAs are being produced that differ from the unedited versions by only a single nucleotide change,” says Kazuko Nishikura, Ph.D., a professor in the Gene Expression and Regulation Program at Wistar and senior author on the study.

“These edited microRNAs are not encoded in the DNA, which means that at least two versions can being produced by one gene. This was not anticipated – it was something really new.

Looking more closely, we realized that the substitution we’d identified occurred in a particularly critical region of the molecule, the first 7 or 8 nucleotides – out of a total of only 19 or 21 – that define the molecule’s target specificity. This suggested that the change might well redirect these edited microRNAs to silence entirely different sets of genes from the unedited versions.”