New paper about how sibling competition and mortality risks affect birth intervals

My very first contribution to the collected sum of human knowledge has just been published in the Journal of Evolutionary Biology. The paper is called: “A Dynamic Framework for the Study of Optimal Birth Intervals Reveals the Importance of Sibling Competition and Mortality Risks” and you can read it online or download a PDF. I’ll talk about the main results in this post.

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Revealing the Menopause?

The egg that eventually became you once lay in your grandmother. This giddy fact(oid) happens because, in the womb, women develop all the eggs they will ever use. The supply gradually declines through the years to the point where no more eggs remain, no more children can be sired: menopause.

But why should fertility grind to a halt several decades before the body gives out? Why lose the ability to reproduce? If life is all about making babies and turning them into baby-making machines themselves (speaking biologically, not philosophically), why run out of eggs but carry on living?
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BioNews: Ageing process determined by mum’s DNA

This week in BioNews, I report on a study showing mousy evidence that genetic mutations inherited from mother may speed up ageing.

Mitochondria are powerhouses, batteries, factories. They provide energy to the cells in your body and without them, you die. One of the cool things about these little bean-shaped organelles is that you inherit them from your mother, not your father. Another cool but slightly scarier fact is that their DNA mutates faster than the DNA in the nucleus of a cell. This means your mitochondria can be prone to accumulating damage throughout life, which may in turn contribute to the ageing process.

The researchers in this study found that mice who inherited already-mutated mitochondrial DNA from their mothers aged prematurely compared to other mice. Have a read.