This series of Science Thriller Mythbusting tackles the most famous of all thriller science myths, the cloning of dinosaurs using DNA extracted from insects preserved in amber.
In 2005, molecular paleontologist Mary Higby Schweitzer made an amazing discovery.
Inside a broken, fossilized femur bone from a Tyrannosaurus rex , she found 68-million-year-old soft tissue. Finding soft tissue is exceedingly rare in fossils and offered a remarkable opportunity to see blood vessel structure and some cells from this extinct creature.
What’s proved to be most useful of all, however, is the protein in the bone matrix. Bone contains a great deal of collagen, a crucial connective tissue protein. It’s found in the bones of all animals, but the collagen amino acid sequence varies from one species to another. Mass spectrometry can be used to determine the amino acid sequence of the dinosaur collagen—and once you have the amino acid sequence, you can reconstruct a possible DNA sequence for the gene that “programmed” the synthesis of the collagen.
Schweitzer and her collaborators did just this, amidst great controversy over the novel methods the scientists had to invent. Opponents argued that the dinosaur specimen was contaminated by present-day organisms. But the Schweitzer group’s approach is being validated, and in 2009 another group replicated the feat with 80-million-year-old hadrosaur connective tissue.
Museums and collectors aren’t in the habit of breaking their fossils, but it’s possible that many existing bone collections have soft tissue inside. Expect to hear more about this effort to learn more about dinosaurs’ place in natural history, based on their collagen amino acid sequences.
It was generally believed that soft tissue couldn’t survive longer than a million years. Perhaps one day, ancient DNA will be recovered in defiance of the conventional wisdom.
(Still want to read more about the Jurassic Park myth? Click here.)