‘Uncategorized’ Archive

Sexual selection and economic growth

I’m not sure how much drive-by traffic gnxp is continuing to receive, but figured it worthwhile to post a note about my latest working paper, which explores whether male signalling may have a role in driving economic progress. The abstract: Sexual Selection, Conspicuous Consumption and Economic Growth The evolution by sexual selection of the male […]

Robustness and fragility in neural development

So many things can go wrong in the development of the human brain it is amazing that it ever goes right. The fact that it usually does – that the majority of people do not suffer from a neurodevelopmental disorder – is due to the property engineers call robustness. This property has important implications for […]

De novo mutations in autism

A trio of papers in this week’s Nature identifies mutations causing autism in four new genes, demonstrate the importance of de novo mutations in the etiology of this disorder and suggest that there may be 1,000 or more genes in which high-risk, autism-causing mutations can occur. These studies provide an explanation for what seems like […]

Nerves of a feather, wire together

Finding your soulmate, for a neuron, is a daunting task. With so many opportunities for casual hook-ups, how do you know when you find “the one”? In the early 1960’s Roger Sperry proposed his famous “chemoaffinity theory” to explain how neural connectivity arises. This was based on observations of remarkable specificity in the projections of […]

I’ve got your missing heritability right here…

A debate is raging in human genetics these days as to why the massive genome-wide association studies (GWAS) that have been carried out for every trait and disorder imaginable over the last several years have not explained more of the underlying heritability. This is especially true for many of the so-called complex disorders that have […]

From miswired brain to psychopathology – modelling neurodevelopmental disorders in mice

It takes a lot of genes to wire the human brain. Billions of cells, of a myriad different types have to be specified, directed to migrate to the right position, organised in clusters or layers, and finally connected to their appropriate targets. When the genes that specify these neurodevelopmental processes are mutated, the result can […]

Jump-starting regeneration of injured nerves

Unlike in many other animals, injured nerve fibres in the mammalian central nervous system do not regenerate – at least not spontaneously. A lot of research has gone in to finding ways to coax them to do so, unfortunately with only modest success. The main problem is that there are many reasons why central nerve […]

Why Eurasians aren’t very pale

A few years ago I wondered offhand why Eurasians weren’t very pale, since East Asians and Europeans developed light skin at different loci over the past few tens of thousands of years. In hindsight the answer seems pretty obvious. I realized the solution when looking at the skin pigmentation loci in my parents’ genotypes. They’re […]

What is a gene “for”?

“Scientists discover gene for autism” (or ovarian cancer, or depression, cocaine addiction, obesity, happiness, height, schizophrenia… and whatever you’re having yourself). These are typical newspaper headlines (all from the last year) and all use the popular shorthand of “a gene for” something. In my view, this phrase is both lazy and deeply misleading and has […]

Does brain plasticity trump innateness?

The fact that the adult brain is very plastic is often held up as evidence against the idea that many psychological, cognitive or behavioural traits are innately determined. At first glance, there does indeed appear to be a paradox. On the one hand, behavioural genetic studies show that many human psychological traits are strongly heritable […]

Human nature and libertarianism

*A cross-post from Evolving Economics There is another interesting topic in this month’s Cato Unbound, with Michael Shermer arguing in the lead essay that human nature is best represented by the libertarian political philosophy. Shermer (rightly) spends most of the essay shooting down the blank slate vision of humans that underpins many policies on the […]

Thoughts on the BGI IQ study

I’ve been following the development of the BGI study on IQ pretty closely. I wanted to note two main caveats people should be aware of with regard to its methodology. First, as with any case-control study, volunteer bias will be an issue. If the cases are a certain class of very smart people, rather than […]

Split brains, autism and schizophrenia

A new study suggests that a gene known to be causally linked to schizophrenia and other psychiatric disorders is involved in the formation of connections between the two hemispheres of the brain. DISC1 is probably the most famous gene in psychiatric genetics, and rightly so. It was discovered in a large Scottish pedigree, where 18 […]

Welcome to your genome

There is a common view that the human genome has two different parts – a “constant” part and a “variable” part. According to this view, the bases of DNA in the constant part are the same across all individuals. They are said to be “fixed” in the population. They are what make us all human […]

Hallucinating neural networks

Hearing voices is a hallmark of schizophrenia and other psychotic disorders, occurring in 60-80% of cases. These voices are typically identified as belonging to other people and may be voicing the person’s thoughts, commenting on their actions or ideas, arguing with each other or telling the person to do something. Importantly, these auditory hallucinations are […]

On the (un)importance of kin selection

While writing a recent short note on Richard Dawkins and kin selection, I looked through my previous posts on the subject, and found what I thought was a blunder in an old post from 2004. To avoid misleading anyone who came across it in a search, I deleted it from the archive. But on further […]

Environmental influences on autism – splashy headlines from dodgy data

A couple of recent papers have been making headlines in relation to autism, one claiming that it is caused less by genetics than previously believed and more by the environment and the other specifically claiming that antidepressant use by expectant mothers increases the risk of autism in the child. But are these conclusions really supported […]

On discovering you’re an android

Deckard: She’s a replicant, isn’t she? Tyrell: I’m impressed. How many questions does it usually take to spot them? Deckard: I don’t get it, Tyrell. Tyrell: How many questions? Deckard: Twenty, thirty, cross-referenced. Tyrell: It took more than a hundred for Rachael, didn’t it? Deckard: [realizing Rachael believes she's human] She doesn’t know. Tyrell: She’s […]

Complex interactions among epilepsy genes

A debate has been raging over the last few years over the nature of the genetic architecture of so-called “complex” disorders. These are disorders – such as schizophrenia, epilepsy, type II diabetes and many others – which are clearly heritable across the population, but which do not show simple patterns of inheritance. A new study […]

Synaesthesia and savantism

“We only use 10% of our brain”. I don’t know where that idea originated but it certainly took off as a popular meme – taxi drivers seem particularly taken with it. It’s rubbish of course – you use more than that just to see. But it captures an idea that we humans have untapped intellectual […]

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