Researchers have, for the first time, recovered and analysed metabolism-related molecules from fossil bones dated 1.3–3 million years, and they report the findings in Nature. The team proposed that metabolites circulating in the bloodstream during life might become trapped in tiny bone niches and persist long term; they tested this idea using mass spectrometry to convert molecules into ions for identification.
After analysing modern mouse bones and identifying nearly 2,200 metabolites (and some proteins such as collagen), the researchers examined fossil fragments from paleontological collections in Tanzania, Malawi and South Africa. The fossils come from species with living counterparts nearby today: several rodents (mouse, ground squirrel, gerbil), an antelope, a pig and an elephant. Analyses produced thousands of metabolites, many shared with modern animals.
The molecules revealed metabolic pathways for amino acids, carbohydrates, vitamins and minerals, and some pointed to genes linked with estrogen, suggesting certain individuals were female. In one case, a 1.8-million-year-old ground squirrel from Olduvai Gorge carried a metabolite unique to the parasite Trypanosoma brucei and showed an anti-inflammatory signature consistent with infection.
Plant metabolites, including forms related to aloe and asparagus, indicated diet and allowed reconstruction of local conditions such as temperature, rainfall, soil and tree cover. These reconstructions align with previous work describing the Olduvai Gorge Bed as freshwater woodland and grassland and the Upper Bed as drier woodlands and marsh. Across the study sites, conditions were wetter and warmer than today. The authors suggest fossil metabolomics could provide a new level of ecological detail about prehistoric environments; the research received support from The Leakey Foundation and technical help from the National Institutes of Health.
Difficult words
- metabolite — small molecule produced by living organismsmetabolites
- mass spectrometry — technique that turns molecules into charged particles
- metabolomics — study of metabolites in biological samples
- pathway — series of chemical reactions in cellspathways
- parasite — organism that lives on another organism
- anti-inflammatory — reduces swelling or immune reaction
- reconstruction — process of creating a past situation from evidence
- collagen — structural protein in animal connective tissues
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- How could finding metabolites that show diet and local climate change our view of ancient ecosystems?
- What practical or ethical issues might arise when researchers sample valuable fossil collections for metabolomics?
- How might evidence of parasites or sex-linked molecules in fossils affect interpretations of individual health or behaviour in ancient animals?
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