Sloths may owe their famously slow lives to 30-million-year-old 'jumping genes'

Genetic clues may help explain why sloths live at such a low gear. In a new study, researchers linked the animals' extremely slow way of life to ancient "jumping genes" connected to mitochondria, the cell structures that generate energy.

What happened?

To investigate, scientists analyzed the genome of the two-toed sloth, Choloepus didactylus, alongside those of dozens of other mammals, according to Science Alert. Their attention centered on transposons — bits of DNA often nicknamed "jumping genes" because they can relocate or copy themselves to new spots in the genome.

The researchers found signs that these elements have stayed active in the sloth lineage for more than 30 million years. Some of the sequences that persisted were associated with mitochondria, which produce energy inside cells, as well as with other genes tied to metabolism.

That genetic pattern may help account for sloths' unusual biology. They have the lowest metabolism of any mammal, are known for their very slow movement, and, unlike many mammals, they do not continuously regulate their body temperature.

Rather than being a disadvantage, those traits may reflect genetic adaptations that developed over millions of years.

Why does it matter?

Biodiversity genomicist Camila Mazzoni of the Leibniz Institute for Zoo and Wildlife Research in Germany said, "Our findings suggest that sloths might have evolved genetic 'backup systems' that help compensate for their 'relaxed mitochondria' and support their unique lifestyle," Science Alert reported.

One possibility is that sloths evolved alternate genetic routes that allow cells to keep functioning under very low energy demands. That has broader relevance because mitochondrial dysfunction is involved in major human health problems, including diabetes, neurodegenerative diseases, muscle wasting, and aging-related disorders.

The study does not mean new treatments are around the corner, but it offers a natural model for how cells can stay healthy under low-energy conditions.

Understanding that process could eventually help researchers studying tissue preservation, critical care, and metabolic disease. Scientists also noted that jumping genes can be harmful in humans and have been linked to diseases, including cancer, meaning any medical lessons will require careful follow-up research.

What are people saying?

Mazzoni said, "Sloths have the slowest metabolism of any mammal, yet they remain healthy. Understanding how they achieve this may reveal new insights into how cells manage energy efficiently."

According to Science Alert, molecular biologist Pedro Galante of Hospital Sírio Libanês in Brazil added, "While further research is needed, sloth cell lines may offer a natural model for understanding how organisms cope with low-energy states, and what goes wrong in disease."

Bioinformatician Marcela Uliano-Silva of the Wellcome Sanger Institute in the U.K. said, "Evolution has already run billions of experiments. By studying unusual animals like sloths, we sometimes uncover biological solutions that humans never evolved."

Genetic research in other areas has unlocked many fascinating avenues to prolong life and treat disease, such as using genetically modified bacteria to fight cancer.

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