‘Dinosaur age’ bird keratin found according to reports in ScienceDaily 21 November 2016, ABC News 24 November 2016 and PNAS doi: 10.1073/pnas.1617168113, published online 21 November 2016.
In recent years scientists studying the microscopic structure of fossil birds and dinosaurs, have found small structures that look like melanosomes, granules containing the pigment melanin. There has been some debate as to whether these really are melanosomes, or microbes that were preserved along with the fossil.
In order to find evidence that these were melanosomes researcher Mary Schweitzer worked with Yanhong Pan, of the Chinese Academy of Sciences and colleagues to study the microscopic structure of feathers of a fossilised bird named Eoconfuciusornis dated as Early Cretaceous, 130 million years old.
Mary Schweitzer of North Carolina State University explained: “If these small bodies are melanosomes, they should be embedded in a keratinous matrix, since feathers contain beta-keratin. If we couldn’t find the keratin, then those structures could as easily be microbes, or a mix of microbes and melanosomes – in either case, predictions of dinosaur shading would not be accurate”.
The fossil bird was found in the Jehol Biota site in China and has well preserved feathers. The researchers examined the feathers using scanning and transmission electron microscopy, and also used a technique known as immuno-gold labelling to identify any preserved keratin. They also examined the distribution of sulphur and copper in the feathers. Sulphur is found in beta-keratin and a number of other proteins, but copper is only found in melanosomes. They found widespread sulphur in the fossil feathers, but copper was found only in the melanosome-like structures. According to ScienceDaily “These findings support both the identity of the melanosomes and indicate there was no mixing or leaching during decomposition and fossilisation”.
The research team wrote in the summary of their report: “Retention of original keratinous proteins in the matrix surrounding electron-opaque microbodies supports their assignment as melanosomes and adds to the criteria employable to distinguish melanosomes from microbial bodies. Our work sheds new light on molecular preservation within normally labile tissues preserved in fossils”. In their conclusion they suggest their methods could be used “to distinguish between keratinous feathers and skin-derived collagen fibres”.
Yanhong Pan commented: “This study is the first to demonstrate evidence for both keratin and melanosomes, using structural, chemical and molecular methods. These methods have the potential to help us understand – on the molecular level – how and why feathers evolved in these lineages”.
Editorial Comment: This was indeed a clever and meticulous study of fossil feathers, but it cannot show how and why feathers evolved. This fossil is definitely a bird, and no-one is claiming it is anything else. All this study can show is what fossil feathers are made of, and it revealed they are made of the same substances found in the feathers of living birds. Therefore, it is evidence that feathers have always been feathers, and have not evolved, no matter how old they are claimed to be.
The term “normally labile tissues” used by the scientists is a reference to the fact that proteins, like all large biological molecules degrade, due to normal chemical processes. The only reason people can stay alive for almost a century is because our proteins are being constantly rebuilt. Once a creature is dead its proteins break down. Keratin is a particularly tough protein because it is exposed to the outside environment as part of its normal function, but it will not last more than a couple of thousand years. Hair is made of keratin, and extremely fragile pieces of hair have been found in old graves and Egyptian mummies. However, even the toughest protein will decay over time by natural chemical processes. Proteins are long strings of small molecules called amino acids joined together by chemical bones known as peptide bonds. Peptide bonds have a half-life of around 400 years. (Ref: Ronald Raines of University of Wisconsin–Madison, Adv Exp Med Biol. 2009; 611: xci–xcviii) This means in 400 years half the peptide bonds will have broken down, in another 400 years half of the remaining half will have decayed, and so on until after 10 half-lives, i.e. 4,000 years there is less than a thousandth of the original peptide bonds still intact, which for a protein with around 100 amino acids means there would effectively be none left. Therefore, the claim that some unknown chemical preservation processes have kept these fossil keratin fibres intact for 130 million years is pure wishful thinking, not observed science.
The reference to distinguishing between collagen and keratin is, no doubt, a challenge to Alan Feduccia, an expert in fossil birds who is sceptical of the claims about feathered dinosaurs made on the basis of dinosaur fossils associated with filaments. Feduccia suggested these are collagen fibres, which are found in skin, becoming flayed out during decomposition of buried creatures. See our report: Dinosaur Feathers or Fibres, here. Whatever the outcome of testing these fossils might show, it would not solve the dilemma of the protein decay time. Like keratin, collagen is also a tough fibrous protein, but not as tough as to endure for millions of years. In spite of this Mary Schweitzer and associates have claimed to have found collagen in dinosaur bones dated as 68 million years old. See our report: T rex Proteins, here.
Evidence News vol. 16 No. 23
6 December 2016
Creation Research Australia
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