The premise of the movie Jurassic Park is that dinosaur DNA was available to clone from blood that a mosquito had ingested before it was trapped in amber. From the movie, you'd think that such mosquitoes were found all the time, enough so that several species of dinosaur could be resurrected. But at the time the movie was made, a blood-engorged mosquito in amber had never been found. However, we now have the next best thing.
About 30 years ago, Kurt Constenius, then a graduate student at the University of Arizona, collected hundreds of insect fossils in Montana and stored them in his parents' basement. Retired biochemist Dale Greenwalt has been collecting fossils for the Smithsonian Museum of Natural History, and the Constenius family decided to donate all those fossils in the basement. Greenwalt noticed that one particular mosquito preserved in shale (not amber) was different.
Staff from the museum’s mineral sciences lab used a number of techniques to scan the specimen up close, including energy dispersive X-ray spectroscopy. “The first thing we found is that the abdomen is just chock full of iron, which is what you’d expect from blood,” Greenwalt says. Additionally, analysis using a secondary ion mass spectrometer revealed the presence of heme, the compound that give red blood cells their distinctive color and allows them to carry oxygen throughout the body. Other tests that showed an absence of these compounds elsewhere in the fossil.
The findings serve as definitive evidence that blood was preserved inside the insect. But at this point, scientists have no way of knowing what creature’s fossilized blood fills the mosquito’s abdomen. That’s because DNA degrades way too quickly to possibly survive 46 million years of being trapped in stone (or in amber, for that matter). Recent research had found it has a half-life of roughly 521 years, even under ideal conditions.
Another divergence from Jurassic Park is that this mosquito is not old enough to have sucked on a dinosaur. We might never know what kind of blood it contained. But now we have evidence that the insects sucked blood millions of years ago. Read the entire story at Smithsonian's Surprising Science blog.
(Image credit: Dale Greenwalt)