Research press release


Nature Communications

Palaeontology: 75-million-year-old cells preserved in dinosaur bones



今回、Sergio Bertazzo、Susannah Maidmentの研究グループは、極めて良好な保存状態とはいえない白亜紀の恐竜の骨化石標本(8点)から有機質構造を発見したことを報告している。これらの化石標本の一部には、核のある赤血球と考えられる構造が含まれており、質量分析計で調べたところ、エミューの血液に似たプロファイルを示した。これ以外にも構造タンパク質であるコラーゲンを含むと考えられる構造が発見された。この構造は、ロープ状にねじれたコラーゲンの特徴的な分子構造を有し、コラーゲンの構成アミノ酸の断片も含まれていた。以上の新知見は、たとえ保存状態の良くない化石であっても分子解析を行う価値がある可能性を示唆している。地質学的時間スケールにわたってタンパク質が保存されていれば、大昔に絶滅した動物の生理と行動を調べられるかもしれない。

Structures that appear to be red blood cells and fibres similar to collagen have been identified in 75-million-year-old dinosaur bones from the Cretaceous, reports a paper in Nature Communications. This find suggests that the survival of organic structures in fossils may far be more common than previously thought.

Components of soft tissue, including structures that look like cells and molecules that resemble proteins, have been found before in fossils many tens of millions of years old, but only in specimens that were exceptionally well preserved and their identification proved controversial. It has long been assumed that protein molecules decay in relatively short periods of time and cannot be preserved for longer than 4 million years, therefore it is generally accepted that only parts of original proteins are preserved and that the full structure has been lost.

Sergio Bertazzo, Susannah Maidment and colleagues now report the discovery of organic structures from eight Cretaceous dinosaur bones, none of which were unusually well preserved. Some of the bones contained structures that appear to be nuclei-containing red blood cells and these exhibited a similar profile to emu blood when tested with a mass spectrometer. Other structures appeared to contain the structural protein collagen, with molecules twisted into the characteristically rope-like structure of collagen and containing fragments of the protein’s constituent amino acids. These findings suggest that even the most unassuming of fossils may be worthy of molecular analysis. The preservation of protein over geological timescales may also allow researchers to investigate the physiology and behaviour of long extinct animals.

doi: 10.1038/ncomms8352


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