Preservation of corneous β-proteins in Mesozoic feathers

Journal Article · Thu Sep 21 00:00:00 EDT 2023 · Nature Ecology and Evolution

DOI:https://doi.org/10.1038/s41559-023-02177-8· OSTI ID:2327098

Slater, Tiffany S. ^[1]; Edwards, Nicholas P. ^[2]; Webb, Samuel M. ^[2]; Zhang, Fucheng ^[3]; McNamara, Maria E. ^[4]

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1. University College Cork (Ireland); SLAC
2. SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL)
3. Linyi Univ. (China)
4. University College Cork (Ireland)

Fossil proteins are valuable tools in evolutionary biology. Recent technological advances and better integration of experimental methods have confirmed the feasibility of biomolecular preservation in deep time, yielding new insights into the timing of key evolutionary transitions. Keratins (formerly α-keratins) and corneous β-proteins (CBPs, formerly β-keratins) are of particular interest as they define tissue structures that underpin fundamental physiological and ecological strategies and have the potential to inform on the molecular evolution of the vertebrate integument. Reports of CBPs in Mesozoic fossils, however, appear to conflict with experimental evidence for CBP degradation during fossilization. Further, the recent model for molecular modification of feather chemistry during the dinosaur–bird transition does not consider the relative preservation potential of different feather proteins. Here we use controlled taphonomic experiments coupled with infrared and sulfur X-ray spectroscopy to show that the dominant β-sheet structure of CBPs is progressively altered to α-helices with increasing temperature, suggesting that (α-)keratins and α-helices in fossil feathers are most likely artefacts of fossilization. Our analyses of fossil feathers shows that this process is independent of geological age, as even Cenozoic feathers can comprise primarily α-helices and disordered structures. Critically, our experiments show that feather CBPs can survive moderate thermal maturation. Importantly, as predicted by our experiments, analyses of Mesozoic feathers confirm that evidence of feather CBPs can persist through deep time.

• Research Organization: SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE Office of Science (SC), Biological and Environmental Research (BER)
• Grant/Contract Number: AC02-76SF00515
• OSTI ID: 2327098
• Journal Information: Nature Ecology and Evolution, Journal Name: Nature Ecology and Evolution Vol. 7; ISSN 2397-334X
• Publisher: Nature Publishing Group
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
biogeochemistry
molecular evolution
paleontology