Yet Another Daily Dose of Science Journalism Fail

From the Daily Mail's website (where else) comes the following headline:

That's a pretty weighty claim. Do babies born via C-section really have lower IQs than those born naturally? What does the article go on to say?

"According to scientists, when women give birth naturally there are higher levels of a special protein in babies’ brains that helps boost intelligence levels as they develop.
Scientists at Yale University in the US say the increased levels of the protein, called UCP2, in babies born naturally could help foster their short and long term memories – key components of the human IQ – as they grow up."

 So according to the Daily Mail, babies born naturally have higher levels of UCP2 in their brains, and this means they have higher IQs. And, as is always the case, the Daily Mail has failed to cite the actual research behind their claim. So, I went ahead and found it for myself¹. What do the original authors have to say?

From their  abstract (emphasis added):

"Mitochondrial uncoupling protein 2 (UCP2) is induced by cellular stress and is involved in regulation of fuel utilization, mitochondrial bioenergetics, cell proliferation, neuroprotection and synaptogenesis in the adult brain. Here we show that natural birth in mice triggers UCP2 expression in hippocampal neurons."

And from their discussion (again, emphasis added):

"The current data suggests that the induction of Ucp2 by birth -associated physiological stress enables metabolic adaptation to a switch available nutrient utilization that is critical for proper survival and development of hippocampal and other brain neurons."

So, in other words, 1) the study was done in mice, and 2) UCP2 levels are correlated with changes in metabolism that were important for brain growth. Nowhere in the paper do the authors mention human babies and nowhere do they mention UCP2 levels having any effect on IQs. One has to wonder whether Sarah Johnson at the Daily Mail actually read the original paper.

Then again, the Daily Mail never really has been good at that science thing. They don't call it the Daily Fail for nothing.

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1. Simon-Areces J, Dietrich MO, Hermes G, Garcia-Segura LM, Arevalo M-A, et al. (2012) Ucp2 Induced by Natural Birth Regulates Neuronal Differentiation of the Hippocampus and Related Adult Behavior. PLoS ONE 7(8): e42911. doi:10.1371/journal.pone.0042911

There's a Pot of Gold at the End of the Brainbow

In the last two years, a new technique has taken the neurobiology world by storm: the Brainbow.
The brainbow is a technique which allows individual neurons in the brain, or sections of the brain, to be mapped by giving them their own special fluorescent colour¹ (see image to the right). It looks pretty, and the technique itself is deceivingly simple.

It takes advantage of something called the Cre/lox system. Cre is an enzyme (a recombinase, to be precise) which will cleave out any DNA that is flanked by sites in DNA with a particular sequence, "lox sites". So if you have Your Favourite Gene (YFG) sandwiched between two lox sites, then Cre will splice YFG out of the DNA. But what if you used two pairs of lox sites? For example, what if you constructed your DNA to look like this:

---lox_A-lox_B--Gene1--lox_A--Gene2--lox_B---

If the lox_A pair is cleaved, then Gene 1 is cut out; if the lox_B pair is cleaved, then Gene 2 is cut out.
The scientists who developed the Brainbow realized that they could use this to make the neurons express one of many different fluorescent proteins. (See image to the left, taken from Nature², click to embiggen) They used nestled lox sites as described above, using multiple fluorescent proteins. The Cre protein is able to cleave a single lox pair, multiple pairs, or no pairs at all. The decision on which pair(s), if any, to cleave is made at random in each cell. What results is a cell that expresses a random colour. If enough colours or colour combinations are Incorporated into the construct, every neuron, in theory, will have its own randomly chosen fluorescent glow. This makes mapping the connections in the brain much easier than ever.

And it makes for pretty artwork too.



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1. Transgenic strategies for combinatorial expression of fluorescent proteins in the nervous system, Nature, November 1, 2007.

2. Neuroscience: Making Connections, Nature, 457, 524-527 (2009)