Showdown: Is Dino Soft Tissue Just Bacteria?
By dismissing dinosaur soft tissue as bacteria, Field Museum scientists may have given creationists a selling point.
Scientists at Chicago’s prestigious Field Museum of Paleontology have made a frontal assault on claims of original dinosaur proteins in dinosaur bones. The claims that soft tissue can be found in some dinosaur fossils, made primarily by Mary Schweitzer at North Carolina State University, and by others, have invigorated young-earth creationists with alleged proof that the bones are only thousands of years old, not tens of millions. Are they wrong? Were they looking at bacterial biofilms masquerading as dinosaur proteins, blood vessels and blood cells?
It’s an old argument revitalized by new experiments. The Field Museum team of 19 paleontologists from a dozen institutions in the US, Canada, Britain and China sawed out some bone from Dinosaur Provincial Park in Alberta, Canada to check. They took precautions to avoid contamination. They found evidence of recent bacteria, but no collagen (bacteria do not make collagen).
Bad news, Jurassic Park fans—the odds of scientists cloning a dinosaur from ancient DNA are pretty much zero. That’s because DNA breaks down over time and isn’t stable enough to stay intact for millions of years. And while proteins, the molecules in all living things that give our bodies structure and help them operate, are more stable, even they might not be able to survive over tens or hundreds of millions of years. In a new paper published in eLife, scientists went looking for preserved collagen, the protein in bone and skin, in dinosaur fossils. They didn’t find the protein, but they did find huge colonies of modern bacteria living inside the dinosaur bones.
“This is breaking new ground—this is the first time we’ve discovered this unique microbial community in these fossil bones while they’re buried underground,” says lead author Evan Saitta, a postdoctoral researcher at the Field Museum. “And I would say that it’s another nail in the coffin in the idea of dinosaur proteins getting preserved intact.”
Avoiding a direct attack on creationists, the press release and paper simply discounts the possibility of dinosaur tissue in the samples they dug up. In addition, it plays up the likelihood that bacteria would be expected in the bones.
Saitta and his colleagues aren’t sure why these particular microbes are living in the dinosaur bones, but he’s not shocked that bacteria are drawn to the fossils. “Fossil bones contain phosphorus and iron, and microbes need those as nutrients. And the bones are porous—they wick up moisture. If you were a bacterium living in the ground, you’d probably want to live in a dinosaur bone,” he says. “These bacteria are clearly having a jolly good time in these bones.”
Whether phosphorus and iron from the age of dinosaurs would be expected to remain after fossilization is not explained. It also seems odd that these bones would contain living bacteria when they have not been described before in other fossils.
An unnamed creationist (unnamed because we did not seek his permission to name him) finds reasons to doubt their conclusions, though. Summarizing his concerns,
- The presence of bacteria in these bones should be problematic to old-earthers.
- Lack of evidence is not evidence of lack. One sample without soft tissue does not rule out others.
- Other paleontologists rigorously detected collagen in other samples.
Thank You Darwin?
Some of the statements by the Field Museum evolutionists are a gift to creationists: they confirm that original dinosaur biomolecules could not possibly have survived 66 million years. If they are proven indeed to be original dinosaur proteins and DNA, and if the samples are not radiocarbon dead, then evolutionists will be up a creek without a paddle. According to their own statements, quoted below, those substances cannot have survived that long, nor can the bones be as old as believed.
From the press release:
- DNA breaks down over time and isn’t stable enough to stay intact for millions of years.
- even they [proteins] might not be able to survive over tens or hundreds of millions of years.
- “Some molecules can survive in the fossil record, but I suspect proteins can’t; they’re unstable on those timescales in the conditions of fossilization.”
- “We found non-radiocarbon dead organic carbon, recent amino acids, and DNA in the bone….”
From the paper in eLife:
- During the fossilization process, biological tissues degrade over millions of years, with some types of molecules breaking down faster than others.
- However, the fossils contained more organic carbon, DNA, and certain amino acids than the sediment surrounding them.
- Fossils have traditionally been thought to retain little original organic material after undergoing decay and diagenesis.
- DNA, which is relatively unstable, is thought to persist no longer than a million years under optimal conditions (Orlando et al., 2013).
A lengthier quote to this effect is reproduced below.** The team’s assertion that some molecules can survive long periods – i.e., “Pigments such as melanin and porphyrins are highly stable and can persist for hundreds of millions of years” – must be read with the background understanding that those are estimates based on (1) a prior commitment to millions of years and (2) the fact that such biomolecules have indeed been found where they were not predicted. Nobody can test hundreds of millions of years.
The situation in this showdown is as follows: opposite secular teams claim to have used careful procedures to test dinosaur bone. The Field Museum team is resurrecting 2008 arguments that the tissues are bacterial biofilms, not original tissues (30 July 2008, original paper in PLoS). But Schweitzer’s many papers reveal her careful techniques to rule out contamination (19 Sept 2017).
It will remain to be seen if Schweitzer and others dispute this paper. Creationists, in the meantime, have found carbon-14 in dinosaur bones (18 June 2015), and Schweitzer is not the only one to have found intact soft tissue. Other scientists have diligently sought to falsify the soft tissue claim, or used multiple methods to determine the nature of the material (1 Dec 2015; see also Bob Enyart’s list of papers). Clear evidence of osteocytes (bone cells) have been detected inside of dinosaur bone by Mark Armitage; those could not have been made by bacteria, which obviously do not have bones.
Secular scientists, understandably, are perturbed by the evidence and would like to dismiss it (see 19 Sept 2017). They have a vested interest in keeping their millions of years. Darwin, their idol, needs the time to evolve humans out of bacteria (as if that were enough time anyway).
The Field Museum paper just came out today, so we will have to see the reaction, and how the arguments shake out. We’ll post any updates here. Update: see the 28 Feb 2020 paper about DNA in dinosaur bone.
**Quote from the eLife paper about molecular survival:
Reports of dinosaur protein and complex organic structure preservation are problematic for several reasons. Firstly, it remains unclear how such organics would be preserved for tens of millions of years. If endogenous, putative dinosaur soft tissues should contain diagenetically unstable proteins and phospholipids (Bada, 1998; Briggs and Summons, 2014), vulnerable to hydrolysis (Eglinton and Logan, 1991; Zuidam and Crommelin, 1995), although the released fatty acid moieties from phospholipids could be stabilized through in situ polymerization into kerogen-like aliphatic structures (Stankiewicz et al., 2000; Gupta et al., 2006a; Gupta et al., 2006b; Gupta et al., 2007a; Gupta et al., 2007b; Gupta et al., 2008; Gupta et al., 2009). At 25°C and neutral pH, peptide bond half-lives from uncatalyzed hydrolysis are too short to allow for Mesozoic peptide preservation, although hydrolysis rates can be decreased through terminal modifications and steric effects on internal bonds (Kahne and Still, 1988; Radzicka and Wolfenden, 1996; Testa and Mayer, 2003). Estimates based on experimental gelatinization suggest that, even when frozen (0°C), relatively intact collagen has an upper age limit of only 2,700,000 years (Nielsen-Marsh, 2002). Secondly, the instances of dinosaur peptide preservation reported are older than the oldest uncontested protein preservation reported by at least an order of magnitude. The oldest non-controversial peptides include partially intact peptides from 3.4 Ma in exceptionally cold environments (Rybczynski et al., 2013), as well as short peptides bound to eggshell calcite crystals from 3.8 Ma stabilized via unique molecular preservation mechanisms (Demarchi et al., 2016). The youngest non-avian dinosaur bones are 66 million years old; on both theoretical and empirical grounds, it seems exceptional that original proteins could persist for so long.