This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Age isn't just a number for one of the ocean's top apex predators. It's a mystery University of Georgia researchers are solving.
A new UGA study has determined how to estimate the age of sharks by analyzing changes to individual animals' DNA. Known as epigenetic clocks, these scientific age estimators focus on chemical alterations known as DNA methylation to measure wear and tear on an animal's cells, providing a noninvasive, fast and accurate assessment of an animal's age. The predictive clock model has been successfully tested in dozens of other animals, but this study marks the first time it's been used in sharks.
The tool can help shed new light on not just the biological evolution of shark populations but also the life cycle of other marine creatures with unknown aging data, the researchers said. "Age structure is one of the most important things conservation biologists can measure," said Benjamin Parrott, corresponding author of the study and an associate professor at UGA's Savannah River Ecology Laboratory and Odum School of Ecology. "If we could figure out how old wild sharks are, we could finally understand the age structure of their populations.
That's incredibly important for conservation of marine populations." The paper is published in the journal Molecular Ecology. The researchers took blood samples from more than 50 zebra sharks across southeastern aquariums, including the Georgia Aquarium. As creatures age, the chemical tags in their DNA change, but predictable patterns emerge over time.
With just 10 different DNA tags, the researchers quickly estimated the zebra sharks' ages within two years of their chronological ages, all without needing to analyze an entire genetic sequence. The estimates were compared with age records from the aquariums to assess accuracy. Given a zebra shark's life expectancy of up to 30 years, that would be comparable to mistaking a person for 26 when they are actually 27.
"The epigenome is a lot like an old barn. It starts out well built, but over time things slowly fall apart," Parrott said. "Our bodies age the same way.
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