Studies of Collagen in Bone and Dentin Matrix of a Columbian Mammoth (Late Pleistocene) of Central Utah

Abstract

A Columbian mammoth, Mammuthus columbi, was excavated at an elevation of 9000 feet in Huntington Canyon, Emery County, Utah. Radiocarbon dates on the skeleton indicated death approximately 11200 years ago. The skeleton was removed from postglacial, Late Quaternary, lake sediments deposited as glacial runoff approximately 9500 years ago. The bones and teeth were especially well preserved in a saturated lake bed. After excavation the bones and teeth were preserved by controlled desiccation, without hardeners, over a period of 9 months. Microradiography, light and electron microscopy, medium and high angle X-ray diffraction, amino acid analysis and cyanogen bromide peptide mapping were undertaken to evaluate the packing, organization, and preservation of collagen in bone and dentin of this mammoth. Microradiography and light microscopy showed that the bone consisted of especially well preserved compact and trabecular bone, and electron microscopy of demineralized bone and tusk showed that the matrix consisted of lamellae of densely packed cylindrical collagen fibrils. Cell remnants with intact nuclei, with or without a nucleolus, as well as variable lengths of plasma membrane were occasionally present on the surface of bony trabecula. Remnants of odontoblast processes were present in some dentin tubules. High and low angle X-ray diffraction demonstrated that the demineralized matrix contained native collagen molecules and amino acid analysis showed that the composition was comparable to that of type I collagen. Cyanogen bromide peptide mapping indicated that the major peptides of type I collagen were present and had the same electrophoretic mobility as that of type I collagen of demineralized Asian elephant bone and rat tail tendon. The excellent quality of preservation of this specimen provided an unusual opportunity to compare the collagen in a matrix that has been preserved for 11200 years to that of modern bone and tooth.