In recent years, researchers have found 1) epithelial cell and osteoclast remnants; 2) the remains of blood vessels, and 3) heme, and hemoglobin components in the partially fossilized Tyrannosaurus rex femur. More recently scientists recovered fragments of the protein collagen from this specimen as well.
John Morris from the Institute of Creation Research writes:
Indeed, it is hard to imagine how soft tissue could have lasted even 5,000 years or so since the Flood of Noah’s day when creationists propose the dinosaur was buried. Such a thing could hardly happen today, for soft tissue decays rather quickly under any condition.
But as compelling as this evidence for a young earth might seem, the preservation of dinosaur soft tissue for 68 million years can be readily explained. For example, see these RTB resources for probable explanations for the T. rex soft tissue.
- Today’s New Reason to Believe: “Dinosaur Blood?” and “Dinosaur Blood—Revisited, Parts 1 and 2” by RTB apologist Greg Moore
- Creation Update: “Sorting Through T. rex Blood Confusion” (March 29, 2005, start listening at around the 15-minute mark) and “More on the Bird-Dinosaur Hypothesis” (April 17, 2007) editions
- Science News Flash: “Scientists Study Evidence Birds Came from Dinosaurs” (April 28, 2008) and “Scientists Question Dinosaur Soft Tissue Find” (July 31, 2008) editions
- RTB 101 dinosaur page
Still, Morris’ question is not unreasonable. Namely, how is it possible for soft tissue to survive for 68 million years? New research from an interdisciplinary team of scientists provides further response to this question by demonstrating how collagen’s structural features allow fragments to survive for eons.1
A Durable Molecule
As I’ve previously pointed out, it is not all that surprising that collagen (or at least fragments of it) could survive 68 million years in an environment devoid of water, oxygen, and microbes given its structure. Collagen’s basic structural unit is called a triple helix, consisting of three protein chains intertwining around each other. At certain points along the triple helix, the individual protein strands are chemically bound to each other to form crosslinks.
Numerous collagen triple helices assemble in a staggered fashion to form a larger structure called a collagen fibril. Large numbers of collagen fibrils in turn assemble, with the aid of other proteins, into collagen fibers.
The highly intertwined, cross-linked structure of collagen makes it reasonable that fragments of this molecule could survive for 68 million years. Even if the individual protein strands break down, the fiber would still remain largely intact because of all the association points. Once the protein strand breaks, the fragments are held in close proximity by the contact points. This forced closeness allows for broken strands to occasionally rejoin and reform the original protein. If the broken strands were not held juxtaposed to each other, the fragments would diffuse away from each other, thus, preventing the reversal of the degradation process.
Finally, collagen’s association with the bone matrix provides added stability to the collagen proteins. Within the bone matrix, collagen fibers adsorb to the mineral component of bone. The contact with the surface protects the protein and keeps the pieces of collagen juxtaposed whenever the protein strands break.
Collagen’s abundance further explains its presence in dinosaur fossils. Collagen fibers comprise one of the chief components of connective tissue, are embedded in the bone matrix, and help form blood vessels. In fact, collagen makes up around 25 to 30 percent of all proteins found in animals.
Young-Earth Creationists Aren’t the Only Skeptics
Despite very good reasons to believe that collagen could survive for tens of millions of years in the matrix of dinosaur bones, some in the scientific community have questioned the soft-tissue finds.2 They claim these materials resulted from bacterial contamination of the fossils with microbially derived structures, thus creating a false appearance of blood vessels and cells. They also argue that the collagen fragments derive from bacterial proteins with structural homology to collagen.
In response to these claims, researchers mapped collagen fragments isolated from the T. rex femur onto molecular models of human and rat collagen fibers. They discovered that the fragments all came from the innermost areas of the fibers, where the strands are packed most closely. These regions are the most protected within the collagen fiber.
If the fragments were due to contamination, they should have mapped randomly onto all regions of the collagen fibers. The fact that the fragments clustered to the most protected areas of the fibers makes better sense if they were generated from dinosaur collagens. The more vulnerable areas of the fibers should break down first, with the most protected ones persisting over time—a type of molecular survival of the fittest.
The mapping study supports the bioauthenticity of the collagen fragments. It also explains why collagen fragments survived for 68 million years and is consistent with my earlier suggestions. As remarkable as the discovery of soft tissue in dinosaur fossils seems to be, it cannot be used to argue legitimately for a young earth.