Archive for May, 2010

Answering Wallace’s challenge: Relaxed Selection and Language Evolution

How does natural selection account for language? Darwin wrestled with it, Chomsky sidestepped it, and Pinker claimed to solve it. Discerning the evolution of language is therefore a much sought endeavour, with a vast number of explanations emerging that offer a plethora of choice, but little in the way of consensus. This is hardly new, […]

What’s in a name? Genetic overlap between major psychiatric disorders

Mirrored from The criteria used to assign patients to specific psychiatric disease categories are set out in the Diagnostic and Statistical Manual of Mental Disorders, published by the American Psychiatric Association. (There is also a World Health Organisation equivalent, the International Classification of Disease). Every so often, these criteria are revised to reflect new […]

Why Johnny can’t read (but Jane can)

Reading is not a skill that comes naturally. Unlike learning spoken language, which the human brain has evolved to absorb almost effortlessly, learning to read is a protracted and difficult process. It involves the categorical association of arbitrary visual symbols with phonemes and also the ability to break words down into component phonemes. It thus […]

Noisy genes and the limits of genetic determinism

Mirrored from Why are genetically identical monozygotic twins not phenotypically identical? They are obviously much more similar than people who do not share all their DNA, but even in outward physical appearance are not really identical. And when it comes to psychological traits or psychiatric disorders, they can be quite divergent (concordance between monozygotic […]

The Jermyn Program

With the detection of Neanderthal admixture in Eurasians (Green et al), evidence for two admixture events in an upcoming paper from Jeffrey Long’s group (probably Neanderthals and erectus), and analysis from Jeffrey Wall and Vincent Plagnol suggesting that some African populations (Pygmies and Bushmen) admixed with other archaic populations, it seems that we are on […]

Cross-societal comparisons then & now

At Discover I have a long review up of Empires and Barbarians: The Fall of Rome and the Birth of Europe. I would recommend the book, especially if you enjoyed The Horse, the Wheel, and Language or Empires of the Silk Road. In any case, I want to highlight two points in the author’s argument […]

Grizzly-Polar bear hybrids in the wild

Timely, Pizzly Bears: Scientists confirmed last week that a bear shot by an Inuvialuit hunter in the Northwest Territories is a second-generation grizzly-polar bear hybrid—a “pizzly” or “grolar” bear. Not that big of a deal. It is likely that polar bears are simply a recent derived variant of brown bear. The main issue not noted […]

“We started with a very strong bias against mixture”

So says David Reich, and he was hardly alone. Why? It was always likely, in fact almost inevitable. I can’t think of a human expansion where there wasn’t some admixture with the locals. I’m serious: why? I’ve certainly heard arguments to that effect, but they were all silly. Intersterility was quite unlikely, if you look […]

Who are the living Neandertals?

I guess now we kind of know.

Is Mental Illness Good For You?

Mirrored from Mental illness is surprisingly common. About 10% of the population is affected by it at any one time and up to 25% suffer some kind of mental illness over their lifetime. This has led some people (many people in fact) to surmise that it must exist for a reason – in particular […]

Loading up on human evolution in PNAS

Click the Early Edition and control-f “Sackler.”

The importance of rare variants in common diseases

In a couple recent posts (and, I remember thanks to google, at least one very old–in internet years–post), I’ve pushed back against criticisms of genome-wide association studies using SNP genotyping arrays. This is despite the fact that I agree it’s clear that rare variants contribute to common diseases, and that sequencing technologies are eventually going […]