Posts Tagged ‘palaeontology’

Neanderthal Man by Svante PaaboNeanderthal Man: In Search of Lost Genomes, Svante Pääbo (Basic Books 2014)

An excellent guide to science in all its aspects, from theory and practice to sociology and politics, describing how scientists think, work, live, love and sometimes cheat. It’s a book about bones, but it made me think about stars. In the nineteenth century, Auguste Comte set an absolute limit on the ambitions of astronomy:

On the subject of stars, all investigations which are not ultimately reducible to simple visual observations are … necessarily denied to us. While we can conceive of the possibility of determining their shapes, their sizes, and their motions, we shall never be able by any means to study their chemical composition or their mineralogical structure … Our knowledge concerning their gaseous envelopes is necessarily limited to their existence, size … and refractive power, we shall not at all be able to determine their chemical composition or even their density… I regard any notion concerning the true mean temperature of the various stars as forever denied to us. — Comte quote

Comte seemed completely right, but was in fact completely wrong. Fraunhofer had already discovered his lines by then and one day astronomers would be using “spectroscopic fingerprints” to “determine the mineralogy of asteroids, the composition of stars, the gravity of white dwarfs, the motions of galaxies, the dynamics of accreting black holes, and more – all from the comfort of a telescope control room” (30-Second Astronomy, ed. François Fressin, 2013).

Comte could have easily have said something similar about palaeontology, but perhaps it seemed too obvious. How much would scientists ever discover from ancient bones? They could weigh them, measure them, compare and contrast them, even analyse their chemical composition, but what would bones ever tell us about the flesh that had once sat on them, about the behaviour of vanished bodies? Very little, it once seemed.

A lot, it turned out, because of something called DNA. This book is about one of the most interesting projects in scientific history: the quest to reconstruct the genome of those long-extinct humans called Neanderthals. Except they’re not entirely extinct, as Svante Pääbo discovered: their genes live on in some modern humans, because we interbred with Neanderthals when we left Africa. Some of us also interbred with a group called the Denisovans, as Pääbo describes too. And there are other groups of archaic interbreeders to be uncovered, inside and outside Africa. Groups of human have separated, evolved differences, and then come together again, but not consistently and completely.

This has big implications for human bio-diversity, or HBD: races are different not just because they’ve evolved to be, but because they’ve interbred to be. Pääbo doesn’t discuss those implications, but there’s no propaganda here about “One Race – the Human Race”. The journey he and his team have begun is going to end in storm and lightning, because Neanderthal genes are doing more than stick around for the ride. They must have physiological and psychological effects, separating those who possess them from those who don’t. Ditto for the Denisovans and others.

So the search isn’t over and this book will have sequels. I look forward to reading them, because Pääbo writes well and engagingly in what isn’t his mother-tongue. Born in Sweden, he’s now “director of Department of Genetics at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany”. For an evolutionary anthropologist, he’s very famous: “In 2009, Time named him one of the 100 Most Influential People in the World”. He describes how he got there, the compromises he had to make and the toes he tried – and sometimes failed – to avoid treading on. But it’s mostly a story of obsession and ingenuity: Pääbo was obsessed with reconstructing a Neanderthal genome and had to be highly ingenious to do so. Luck and hunches were important too:

Most labs discard side fractions as by-products. Fortunately we had saved all of ours from our previous experiments. For years I had insisted on doing so, just in case something came along that would make them useful. This was easily one of my least popular ideas and caused many freezers to be filled with frozen side fractions that no one thought would ever be used. But thankfully in this case the crazy idea of the professor had been adhered to by the group. So now Tomi could simply heat the side fractions from earlier preparations from the Vindija bones and retrieve additional, relatively copious amounts of Neanderthal DNA without having to do any more extractions. (ch. 13, “The Devil in the Details”, pg. 145)

Pääbo is writing a popular account, so there isn’t a lot of technical detail, but there’s more than enough to be impressive. Genetics isn’t stamp-collecting: it requires serious intellect and nowadays serious computer-power and programming too. Pääbo couldn’t do all of that on his own: modern science is a collaborative endeavour. He directs a team and this book describes their ingenuity and idiosyncrasies. But in a way they’re a burial party. Science is now measuring mankind for its coffin. The more we know about ourselves, the more we will be able to surpass ourselves. This book about an obsessive human is also an early obituary for the human race.

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