Two by Ed Yong

Ed Yong always brings even simple stories alive with an interesting twist, an analogy, or just good writing. Here are links to two of his stories from late this week ... with a taste of each.

Ed Yong, Why type 2 diabetes is a bit like The Bourne Identity

In The Bourne Identity, the eponymous hero is presumed dead by his former employers, but turns out to have merely lost his memory. Thus unburdened, he attempts to change his fate.

Which reminds me of diabetes.

People with type 2 diabetes face two problems, both related to insulin – the hormone that regulates the levels of sugar in our blood. They don't respond properly to it (they become insulin resistant), and they don't make enough of it. As a result, the levels of sugar in their blood become too high. Insulin resistance is fairly steady throughout a person's lifetime, but the failure to make insulin gets progressively worse. The typical explanation is that the beta-cells – a type of insulin-making cells within the pancreas – die off.

But Domenico Accili from Columbia University has a different idea. By studying diabetic mice, he has found beta-cells do indeed disappear over time, but not because they die. Instead, they revert back to a more basic type of cell that doesn't produce insulin. Like Jason Bourne, they lose their former specialised identities and become more of a tabula rasa. In the film, it's simple memory ...

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Ed Yong, Why do killer whales go through menopause?

Here's yet another reason why humans are weird: menopause. During our 40s, women permanently lose the ability to have children, but continue to live for decades. In doing this, we are virtually alone in the animal kingdom. From a cold evolutionary point of view, why would an animal continue to live past the point when it could pass on its genes to the next generation? Or put it another way: why don't we keep on making babies till we die? Why does our reproductive lifespan cut out early?

One of the most popular explanations, first proposed in the 1966, involves helpful grandmothers. Even if older women are infertile, they can still ensure that their genes cascade through future generations by caring for their children, and helping to raise their grandchildren.* There's evidence to support this "grandmother hypothesis" in humans: It seems that mothers can indeed boost their number of grandchildren by stepping out of the reproductive rat-race as soon as their daughters join it, becoming helpers rather than competitors.

Now, Emma Foster from the University of Exeter has found similar evidence among one of the only other animals that ...