Comment on Scientists and the Temptation to Bias Results by Peter.
Sean Pitman wrote: “The really amazing thing is that there are soft tissues at all – to include sequencable antigenic proteins and even fragments of DNA in dinosaur bones dating from 60Ma to more than 150Ma (Link). Just a few years ago science had shown, by kinetic chemistry experiments, that such soft tissues and proteins should have been completely degraded within less than 100 ka. The current argument that iron helps to preserve soft tissues like formaldehyde doesn’t really solve the problem of protein kinetic chemistry decay.”
Sean, when you analyze the literature, you seem to accept as gospel truth those papers that support your views, and dismiss all others that contradict your views. One example is the theoretical models that address the degradation or persistence of biomolecules (I say theoretical, because the conclusions are based on extremely short-term results extrapolated to extreme periods of time). Here, you seem to insist that the models are inviolable representations of reality, and trump any kind of empirical observations that might contradict them.
So what do you know about the assumptions of these models? Are they accurate and do they hold in every situation? Clearly, they account for age, but do they assume that time is more important for degradation of biomolecules than specific environmental conditions? Are they based on data from benchtop experiments that employ potentially unrealistic conditions as proxies for time and degradation? Do they accommodate the possibility of factors that might slow down the degradation process, such as the stabilizing influence of close mineral association on molecules? Do they account for variation in water/humidity and thermal history? Do they rule out deamidation, strand breaks, backbone cleavage, post mortem modifications, abnormal cross-links, oxidation, and base or amino acid alteration and/or substitution that could affect the longevity of biomolecules?
As you are well aware, Mary Schweitzer is making rapid headway in exploring the conditions that might substantially delay the degradation process that you seemingly regard to do be inviolable. Are you fully confident that her efforts are useless; that the models account for, or properly disregard, all possible sources of environmental variation that could affect the rate of decay? Perhaps you have expertise to invalidate her claims, for example, that the molecular structure of collagen and keratin could contribute to molecular preservation over deep time, and that iron might also stabilize organic molecules by forming protective surface nanoparticles and cross-links that help to “fix” the tissues. If so, where, specifically, is she wrong with her data-based interpretation that biomolecule degradation rates may be much more variable than the laboratory-based studies allow? And does it really help your (our) position to use the laboratory-based conclusions when they still allow for a far, far greater time frame for biodegradation–and the presence of soft tissue in dinosaur bones–than a few thousand years?
I would be elated if Schweitzer was proven to be wrong in the direction she is going. However, your closed mind on this issue, quite frankly, is a genuine turn-off. I really don’t think you know what you are talking about (which, of course, is the exact language you apply to everyone who disagrees with you, and I expect it to come right back at me). Please tell us why the papers summarizing the laboratory-based “kinetic chemistry experiments” are to be believed on their own merit (apart from your bias) rather than the papers that challenge them based on actual findings in real-world environments. Is it at all conceivable, to you, that the laboratory-based papers are overly simplistic?
