Preservation potential of keratin in deep time.

Mary Higby Schweitzer,Wenxia Zheng,Johan Lindgren,Alison E Moyer,Peter Sjövall,Yogendra Kumar Mishra

doi:10.1371/journal.pone.0206569

Abstract

Multiple fossil discoveries and taphonomic experiments have established the durability of keratin. The utility and specificity of antibodies to identify keratin peptides has also been established, both in extant feathers under varying treatment conditions, and in feathers from extinct organisms. Here, we show localization of feather-keratin antibodies to control and heat-treated feathers, testifying to the repeatability of initial data supporting the preservation potential of keratin. We then show new data at higher resolution that demonstrates the specific response of these antibodies to the feather matrix, we support the presence of protein in heat-treated feathers using ToF-SIMS, and we apply these methods to a fossil feather preserved in the unusual environment of sinter hot springs. We stress the importance of employing realistic conditions such as sediment burial when designing experiments intended as proxies for taphonomic processes occurring in the fossil record. Our data support the hypothesis that keratin, particularly the β-keratin that comprises feathers, has potential to preserve in fossil remains.

Highlights

The vast majority of data from extinct vertebrates derive from biomineralized remains
We have demonstrated that, at least for samples subjected to the conditions described keratin seems to have higher preservation potential than melanosomes, which are not seen in Transmission electron microscopy (TEM) of either the feathers exposed to high heat or the coot feathers
Repeatedly and using multiple lines of evidence [16, 17, 75, 76], that sauroposid β-keratin products are extremely resistant to degradation under some conditions, and survive at the molecular level such that they are recognizable by specific antibodies over geological time

Summary

Introduction

The vast majority of data from extinct vertebrates derive from biomineralized remains (e.g. bones and teeth). [1]); this suggests that natural mechanisms exist to stabilize these materials before degradation is complete [2] Whether this exceptional morphological preservation extends to the molecular level has not, in most cases, been rigorously tested. In part, this is because existing models of fossilization assume extensive diagenetic alteration, such that original components are completely degraded or unrecognizable in their fossil form [3]. This is because existing models of fossilization assume extensive diagenetic alteration, such that original components are completely degraded or unrecognizable in their fossil form [3] This supposition is based upon kinetic models or extrapolation of small data sets to the larger fossil record By both erecting and testing hypotheses through actualistic experiments (e.g. [8,9,10,11]) and by deriving data from fossils

Methods

Results

Discussion

Conclusion