Ancient amino acids from fossil feathers in amber

Abstract

Ancient protein analysis is a rapidly developing field of research. Proteins ranging in age from the Quaternary to Jurassic are being used to answer questions about phylogeny, evolution, and extinction. However, these analyses are sometimes contentious, and focus primarily on large vertebrates in sedimentary fossilisation environments; there are few studies of protein preservation in fossils in amber. Here we show exceptionally slow racemisation rates during thermal degradation experiments of resin enclosed feathers, relative to previous thermal degradation experiments of ostrich eggshell, coral skeleton, and limpet shell. We also recover amino acids from two specimens of fossil feathers in amber. The amino acid compositions are broadly similar to those of degraded feathers, but concentrations are very low, suggesting that much of the original protein has been degraded and lost. High levels of racemisation in more apolar, slowly racemising amino acids suggest that some of the amino acids were ancient and therefore original. Our findings indicate that the unique fossilisation environment inside amber shows potential for the recovery of ancient amino acids and proteins.

Non-Avian Dinosaur Eggshell Calcite Contains Ancient, Endogenous Amino Acids

“…One difficulty in searching for ancient proteins comes from environmental and laboratory contamination (Buckley et al 2008(Buckley et al , 2017Bern et al 2009). There is mixed evidence that amber might act to trap some ancient amino acids, but the amino acid profiles and racemization patterns are not what would be expected from a closed system of ancient amino acids (McCoy et al 2019;Barthel et al 2020). Examining proteins deposited within biomineralised calcium carbonate (intra-crystalline) helps to mitigate this issue.…”

Variations of Mesozoic feathers: Insights from the morphogenesis of extant feather rachises

“…Feather keratin is extremely resistant to water and organic solvents (Moyer et al 2016;McCoy et al 2019). Although fossilization in resin flows can disturb the original orientation of constituent feather branches such as barbs and barbules, the rachidial structures remain mechanically unaltered and are usually better preserved than other parts of the feather (Zhao et al 2020).…”

“1984”: What Orwell could not predict. Proteomic analysis of his scripts

“…McCoy et al. [30] recovered ancient amino acids from fossil feathers in amber and showed that the unique fossilisation environment inside amber permitted exceptionally slow racemisation rates. Since the phylogenetic relationships between hominins of the Early Pleistocene epoch in Eurasia, such as Homo antecessor , and later humans, such as Homo sapiens , are highly debated.…”