Tiny DNA Traces Detected in Turtle Fossil From 6 Million Years Ago; Discovery Could Boost Understanding of Soft Tissue Preservation

Researchers found a compound that exhibits consistencies with DNA in a preserved Leipdochelys fossil turtle that dates back to Panama's Late Miocene Chagres Formation.

turtle fossils
Pixabay / Icewall42

Sea Turtles

Sea turtles may have been on Earth for over 110 million years, despite this, little remains known about these creatures and their evolution.

At present, there are only seven known sea turtle species. Two of these belong to the Lepidochelys genus. These are the Lepidochelys kempii (Kemp's ridley sea turtle) and the Lepidochelys olivacea (olive ridley sea turtle). Both of these could aid with the understanding of the evolution and biology of sea turtles.

Back in 2015, a paleontological team found sea turtle remains in the Chagres Formation on the Caribbean coast of Panama. The finding serves as the oldest fossil sea turtle evidence that has ever been spotted.

It is estimated that this creature lived around 6 million years ago during the epoch of the Late Miocene. During this period, the world was becoming drier and cooler. Ice was building up at the poles while sea levels decreased as rainfall reduced.

The creature exhibited a characteristic feature among Lepidochelys. More specifically, the specimen had anteroposteriorly short and rectangular pleural scutes.


DNA Found in Turtle Shell Fossil

Interestingly, aside from finding the oldest Lepidochelys on record, paleontologists also unexpectedly found DNA traces in the sample. Findings were detailed in a published study. The researchers were able to find osteocytes, which are bone cells. These cells are the most abundant ones among vertebrates. Their structures are similar to nuclei.

The researchers performed a solution known as DAPI for testing the bone cells for genetic traces. Dr. Edwin Cadena, the study's lead author and a research associate from Panama's Smithsonian Tropical Research Institute, explains that some bone cells had preserved nuclei that reacted to the DAPI solution, which enabled them to pick up DNA remains. This marks the first time they document DNA remains in a millions-of-year-old turtle fossil.

The sample could have vital implications for molecular paleontology. Specialists in this field study prehistoric biomatter, including lipids, proteins, carbohydrates, and DNA that could be taken from fossilized remains.

Now, this sea turtle specimen could aid in understanding soft tissue preservation. It could also help challenge the paradigm that biomolecules like DNA or proteins have a specific preservation timeline among fossils. It may further encourage the further re-examination of specimens for biomolecule traces.

Check out more news and information on Paleontology in Science Times.

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