It must be frustrating to be a palaeontologist announcing anything to do with mosquitoes. Dale Greenwalt from the US National Museum of Natural History in Washington DC (and a team of fellow researchers) has found a fossil of a female mosquito with an engorged abdomen – that is, it’s full of blood. But before you begin looking for a Pacific island on which to build your Jurassic Park, it’s really not going to let us clone dinosaurs. Really. Stop dreaming, it’s not happening.
First, here’s Ed Yong of Nature laying out the discovery:
Although scientists have found fossils of suspected blood-sucking insects, the creatures’ feeding habits have mostly been inferred from their anatomy or the presence of blood-borne parasites in their guts. But Greenwalt’s fossilized mosquito contains molecules that provide strong evidence of blood-feeding among ancient insects back to 46 million years ago. It is a fortunate find. “The abdomen of a blood-engorged mosquito is like a balloon ready to burst. It is very fragile,” says Greenwalt. “The chances that it wouldn’t have disintegrated prior to fossilization were infinitesimally small.”
In Jurassic Park, it’s all about amber, which preserved the mosquitoes and protected the dinosaur blood from decaying – Richard Attenborough even has a chunk of it on the end of his cane, it’s that important.
But in real life, this is the first time that any such blood-carrying mosquito this old has been found – and it’s not even amber, it was found in shale rock. Plus, there’s so little blood – or, rather, trace materials like iron and porphyrin (both stuff that makes up haemoglobin) – that they could only prove that it wasn’t organic matter from the mosquito itself because a male mozzie had also been fossilised (with empty belly) right next to the female. Since males don’t drink blood, that helped the scientists prove the female had a full stomach when it died.
But it’s a mosquito with blood in it, so we can clone a dinosaur now, right? Sorry, nope. Not even close. First, this mosquito died 19 million years after the dinosaurs are believed to have become extinct. So that isn’t dinosaur blood.
Secondly, and much more importantly, is that we are never going to be able to clone a dinosaur this way because DNA cannot survive in a useable form for much more than a few thousand years at best. That’s because it has a half-life of roughly 500 years.
Half-lives are usually used when talking about radiation, and mean the amount of time it takes half of something to decay (on average). So for uranium that’s 703.8 million years, which explains why we can still find some in the ground despite the Earth being roughly 4.5 billion years old.
Experiments conducted on bird bones and with bees preserved in amber have shown that DNA’s half-life is likely 521 years on average, and that trying to find traces of useable DNA in fossils is pretty much pointless in anything older than 10,600 years. Groups of scientists around the world are trying very hard to clone 10,000-year-old mammoths found frozen in the Arctic tundra, and they’re struggling despite finding stuff like actual, non-fossil blood and cells.
In fact, this mosquito is a remarkable discovery just for what it is, not for any science fiction fantasies. We now have proof that mosquitoes were blood-sucking nuisances even 19 million years ago, and this is only the fifth time a fossilised blood-sucking insect has been found. It also confirms earlier, controversial discoveries of seemingly-intact blood cells within other dinosaur fossils – cells which nobody thought could last that long.
So it’s not all bad. Just don’t tell Richard Attenborough. He will be very disappointed.
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