Evidence of proteins, chromosomes and chemical markers of DNA in exceptionally preserved dinosaur cartilage

Alida M Bailleul; Wenxia Zheng; John R Horner; Brian K Hall; Casey M Holliday; Mary H Schweitzer

doi:10.1093/nsr/nwz206

Evidence of proteins, chromosomes and chemical markers of DNA in exceptionally preserved dinosaur cartilage

Natl Sci Rev. 2020 Apr;7(4):815-822. doi: 10.1093/nsr/nwz206. Epub 2020 Jan 12.

Authors

Alida M Bailleul^{1

2}, Wenxia Zheng³, John R Horner⁴, Brian K Hall⁵, Casey M Holliday⁶, Mary H Schweitzer^{3

7

8}

Affiliations

¹ Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China.
² CAS Center for Excellence in Life and Paleoenvironment, Beijing 100044, China.
³ Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA.
⁴ Honors Program, Chapman University, Orange, CA 92866, USA.
⁵ Department of Biology, Dalhousie University, Halifax, B3H 4R2, Canada.
⁶ Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO 65211, USA.
⁷ North Carolina Museum of Natural Sciences, Raleigh, NC 27601, USA.
⁸ Department of Geology, University of Lund, 22362, Sweden.

Abstract

A histological ground-section from a duck-billed dinosaur nestling (Hypacrosaurus stebingeri) revealed microstructures morphologically consistent with nuclei and chromosomes in cells within calcified cartilage. We hypothesized that this exceptional cellular preservation extended to the molecular level and had molecular features in common with extant avian cartilage. Histochemical and immunological evidence supports in situ preservation of extracellular matrix components found in extant cartilage, including glycosaminoglycans and collagen type II. Furthermore, isolated Hypacrosaurus chondrocytes react positively with two DNA intercalating stains. Specific DNA staining is only observed inside the isolated cells, suggesting endogenous nuclear material survived fossilization. Our data support the hypothesis that calcified cartilage is preserved at the molecular level in this Mesozoic material, and suggest that remnants of once-living chondrocytes, including their DNA, may preserve for millions of years.

Keywords: DNA markers; cartilage; chromosomes; collagen II; dinosaur; nuclei.