Power, Sex, Suicide: Mitochondria and the Meaning of Life

by Nick Lane

Power, Sex, Suicide is the best general science book I’ve read in years. In terms of the synthesis of current research and the ability to convey startling and complex ideas in a manner approachable to non-specialists, it compares favorably with Dawkins’ The Selfish Gene—which is saying quite a lot.

Lane presents a compelling and convincing case that mitochondria are the key to the development of complex life. While it is generaly well-known that they are the vestigial remains of once independent bacteria that were symbiotically incorporated into other simple cells, the impact of this relationship is only now becoming fully appreciated.

With their small size, bacteria compete for resources by the sheer speed with which they can reproduce. This directly limits the size of their genome since larger DNA strands take longer to replicate. He shows why this was an “evolutionarily stable strategy”- effectively a feedback loop which selects for the small and simple.

By incorporating other bacteria to perform their energy producing requirements, early eukaryotic cells became untethered from this basic constraint, which led to the great flowering of complexity.

Through gene transfer, most of the midochondrial DNA has been incorporated into the host nucleus leaving only a small set of genes behind (13 in the case of Homo sapiens). These genes being targets of natural selection, the mitochondria are still acting in their own best interest but in the context of the symbiotic relationship with their host.

Some sections, for example, on the development of sex are more speculative and somewhat less convincing, but the overall work is audacious and eye-opening.