Shining Like a Ground Beetle — my review of Darwin’s nerdy birthday party

Week before last, I went to Darwin’s Birthday Party at the Natural History Museum in London. The next day, I scribbled about it for Pi Media. Read the review here:

What follows is a version with hyperlinks:

. . .

Commuters in London’s Waterloo Station during the 1960s may not have realised the shaggy man sitting alone on a bench, casting himself outside the bustle, was about to revolutionise evolutionary biology.
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A Bit of a Do

You walk into a bar, order a pint, scan a QR code and sit down. This is not only the beginning of a tedious joke but also how you pay for booze with Bitcoins.

But did you really pay for that pint? What on earth is a Bitcoin? As you sip the spumous ale, consider what normally occurs: you’d hand over a sheet of paper, you’d get a handful of metal discs back. You’d sit down as if nothing was weird about that transaction.
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Y: The (not quite) Last Man

Human males will not exist in five million years’ time. So goes a popular line of thinking. But maybe it’s not quite right.

This week for BioNews, I report on a study that draws on 16 complete, high-coverage genomes and a bunch of mathematical models to show that the ‘male’ Y chromosome will be sticking around for a while. The little bastard may contain only 27 genes but they seem to be 27 genes that natural selection is holding onto.

Have a read.

Reference: Wilson Sayres, Lohmueller & Nielsen (2013). Natural selection reduced diversity on human Y chromosomes PLOS Genetics DOI: 10.1371/journal.pgen.1004064

Peter Grindrod’s 10 Miles of Mars

Way back in 2013, I interviewed Dr Peter Grindrod for UCL’s student magazine, Pi. Dr Grindrod is a planetary scientist who also puts a lot of time into outreach activities. Last year, he curated a photography exhibition at UCL called 10 Miles of Mars — a huge Martian panorama.

An edited version appears in the magazine (you can read it on page 24 of the online magazine). Here is the full interview.

10 Miles of Mars (source: Londonist)
10 Miles of Mars (source: Londonist)

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A sigh of relief after the moan

Yesterday, I got annoyed by the reporting of a study supposedly showing evidence for ‘female brains’ and ‘male brains’.  A lot of the rest of the internet got annoyed, too.

Dorothy Bishop kicked it all off early yesterday morning and storified the entire proceedings (embedded at the bottom of this post).

Tom Stafford wrote a great critique on The Conversation.

University College London’s Sophie Scott blogged about some technical queries.

@RidgwayGR even calculated the (tiny) effect sizes that were missing/unreported in the original study.

Finally, the wonderful Cordelia Fine (author of Delusions of Gender) raised questions about the study’s interpretations, stereotyping, neurosexism and everything else iffy with it.

In her critique, Dr Fine cites a piece that she co-authored, published last month in Trends in Cognitive Sciences (annoyingly stuck behind a paywall). I’d love to paste the whole thing here, but I’ll rein myself in and leave you with two choice quotes:

“Assumptions that brain circuitry is largely fixed by a genetic blueprint, that there is a unidirectional, causal pathway from genes to behavior via hormones and brains, and that evolution has left us with brains and mental processes strongly reminiscent of our Paleolithic ancestors, have been widely rejected following conceptual and empirical upheavals in the relevant scientific fields.”

“The relations between science and society are two-way. Scientists who work in politically sensitive and important areas have a responsibility to recognize how social assumptions influence their research and, indeed, public understanding of it. Moreover, they should also recognize that there are important and exciting opportunities to change these social assumptions through rigorous, reflective scientific inquiry and debate.”

A quick moan about ‘male’ and ‘female’ brains

This morning, all the newspapers are talking about ‘male brains’ and ‘female brains’. A study, published in the top-tier journal PNAS, analyses structural differences between the brains of young males and females aged eight to 22 years.

Their findings apparently support age-old stereotypes of female brains ‘designed for’ social skills, memory, intuitive thinking, and male brains ‘designed for’ co-ordinated tasks, perception. Indeed the senior author, Ragini Verma, is quoted in The Guardian as saying: “I was surprised that it matched a lot of the stereotypes that we think we have in our heads. If I wanted to go to a chef or a hairstylist, they are mainly men.”

The Independent’s front page looks like this:

and they headline an article: “The hardwired difference between male and female brains could explain why men are ‘better at map reading’

The Huffington Post quite wildly claims: “A new study has confirmed that men and women’s brains are wired in completely different ways, as if they were species from different planets.”

The Guardian takes a more sober, though still uncritical line and the less said about the Mail’s stereotype-ridden take, the better.

The researchers used a technique called diffusion tensor imaging, which I’m far from qualified to comment on. Using this, they mapped the connections between neurons in the brains of 949 ‘youths’ (428 male).

My problems are two-fold and both relate to the sample analysed in this study.

First, the reporting of the analyses: they don’t mention the magnitude of any differences they found – that is, they do not report effect sizes. Several times, they refer to their sample of 949 as ‘large’ or ‘very large’. Certainly, the sample is over twice that of a previous study (439 people). One thing larger samples let you do is look for smaller effect sizes that are still statistically significant. But we just don’t know what the effects were.

Second, who formed their sample. They studied people aged 8 to 22 years, all recruited from either the University of Pennsylvania or the Children’s Hospital of Philadelphia. They have a fair spread of ethnic diversity within their sample – 44 percent are “Caucasian, not Hispanic” and 40.5 percent are “African American, not Hispanic”, for example. However, the people in their sample may well have grown up in not-dissimilar ways, received similar amounts or quality of education and so on. (We don’t know this, since they only account for individual age and [their words] ‘race’.)

Without looking at variation in upbringing (and the ilk), we can’t discount social or cultural effects – perhaps children growing up in an American culture that says “men should be like this” and “women should be like that” will push them down particular paths, affecting how their brain structures develop. I don’t know, but neither do the researchers.

We cannot talk about ‘hardwired’ differences between female and male brains without understanding the genetic factors, the environmental factors and the interactions and feedbacks between them.

Also, their sample is what has been referred to as WEIRD. That is, Western, Educated, Industrialised, Rich and Democratic. You cannot generalise to all humans from this sample, as the newspapers and as the researchers themselves have been doing.

I’m not saying the researchers ‘should’ have studied a wider, cross-cultural sample who have grown up in and been exposed to different environments – but it’s something to consider before we start saying “women are X” and “men are Y” or, worse, “women should be X” and “men should be Y”.

Madhura Ingalhalikar, Alex Smith, Drew Parker, Theodore D. Satterthwaite, Mark A. Elliott, Kosha Ruparel, Hakon Hakonarson, Raquel E. Gur, Ruben C. Gur, & Ragini Verma (2013). Sex differences in the structural connectome of the human brain PNAS DOI: 10.1073/pnas.1316909110

Genetics and pesticide exposure ‘double hit’ might underlie Parkinson’s (for some)

This week for BioNews, I report on a thorough and thoroughly cool study that weaved its way down a biological pathway from exposure to pesticides to the death of nerve cells linked to Parkinson’s disease.

The researchers found how a genetic mutation can interact with toxins produced from pesticides to disrupt the functioning of neurons involved in movement and coordination. The mutation lies in a gene encoding a protein that is the main ingredient of Lewy bodies — the clumps found among neurons of people with Parkinson’s or certain forms of dementia.

They looked at the problem from all sorts of angles and involved patient-derived lines of induced pluripotent stem cells and embryonic stem cells and a lot of tweaking, coming to firm causal conclusions about a very particular interaction between genetics and environmental factors.

Have a read.