A new study published in Nature reports the extraction and analysis of metabolism-related molecules from fossil bones dated between 1.3 and 3 million years. The research team tested the idea that molecules carried in life could become trapped in tiny spaces in bone and remain over time.
Scientists first analysed present-day mouse bones and identified nearly 2,200 metabolites, and they also detected proteins such as collagen in some samples. They then examined fossil fragments from sites in Tanzania, Malawi and South Africa, from species with living counterparts: several rodents, an antelope, a pig and an elephant.
The molecular results revealed biological processes such as amino-acid, carbohydrate and vitamin metabolism. Some molecules pointed to genes linked with estrogen, suggesting certain animals were female. One 1.8-million-year-old ground squirrel from Olduvai Gorge showed a metabolite of the parasite Trypanosoma brucei and signs of an anti-inflammatory response, consistent with infection.
Plant metabolites, including types related to aloe and asparagus, helped reconstruct temperature, rainfall, soil and tree cover. These reconstructions agree with earlier descriptions of Olduvai Gorge layers, and across the sites conditions were wetter and warmer than today.
Difficult words
- metabolite — Small molecule produced by living organismsmetabolites
- metabolism — Chemical processes that keep living things workingmetabolism-related
- collagen — Structural protein in bones, skin and tissue
- parasite — Organism that lives on and harms another
- reconstruct — To build a past situation from evidence
- anti-inflammatory — Reducing swelling and pain in tissues
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- Would you be surprised that molecules can survive for millions of years? Why or why not?
- How can finding signs of infection in a fossil animal help scientists understand the past?
- Do you think studying plant metabolites is a useful way to learn about ancient climate? Explain your opinion.
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