Joyce Chen ’23
Despite significant technological advances in the past decade, a great deal of mystery still surrounds the ancient animals that once roamed the earth. In order to learn about these organisms, biologists study the biomolecules that are found within fossils. Biomolecules include proteins and lipids, and their preservation allows scientists to understand and trace evolution. Due to a lack of research on the topic, Dr. Caitlin Colleary of Virginia Polytechnic Institute and her team investigated the preservation of biomolecules in ancient mammoth ribs across several environments to understand how biomolecules are conserved in related species.
Several different mammoth ribs along with a modern African elephant rib were collected from various locations. The team aimed to compare the elephant bone fragment with the mammoth ribs. Also known as a maturation experiment, the bones were cut and heated in ovens for different time intervals, ranging from 24 hours to 91 days. Amino acids within the bone were measured using time-of-flight secondary ion mass spectrometry (TOF-SIMS) and lipids were extracted from the bones for analysis. The presence of endogenous biomolecules such as amino acids and lipids help determine how well-preserved the fossil is; fossils that have the same amount of endogenous lipids as modern elephant bones are deemed as well-preserved, while fossils with exogenous lipids from external sources like soil are deemed as contaminated.
Additionally, the preservation of biomolecules is related to the environmental conditions in which the fossil was found. Factors like temperature seem to have a particularly large influence on lipid preservation. The team discovered that the mammoth bone collected from a hot spring showed high levels of degradation due to the presence of high amounts of exogenous lipids. Meanwhile, the fossil from a permafrost area was the best preserved out of all of the collected bones due to the high levels of endogenous lipids. However, a bone from a channel deposit showed higher amounts of endogenous lipids than the permafrost bone. Thus, the burial environment has a large impact on biomolecule preservation.
Dr. Colleary and her research team’s study demonstrates the importance of the environment on biomolecule preservation within ancient fossils. Further studies will be conducted to take into account the contamination of fossils within their environment and how this plays a role in degradation of fossil bones.
 C. Colleary, et al., Molecular preservation in mammoth bone and variation based on burial environment. Sci Rep 11, 2662 (2021). Doi: 10.1038/s41598-021-81849-6