Scientists Revive Worms Frozen For 46,000 Years

Jul 31, 2023

Imagine going down for a long nap in the ice age and waking up in the present.

That’s what happened to a half-dozen tiny roundworms that were 46,000 years old. They were revived by scientists after having survived dormant in Siberian permafrost. The peer-reviewed discovery was announced in the journal PLOS Genetics

The worms had survived by being in a dormant state called cryptobiosis. In that state, they stopped eating. And their metabolism dropped to an undetectable level. The researchers used radiocarbon dating to learn the age of the worms.  They figured out that the worms were frozen between 46,000 and 48,000 years ago. 

The worms are called nematodes. They are one of Earth’s most common life forms. They're known for surviving long stretches locked in ice. This finding, though, destroyed the old record held by a nematode brought back from cryptobiosis. That one survived for a mere 25 years before being revived.

The Siberian worms are a new species. Scientists thawed them out in 2018. They named them Panagrolaimus kolymaensis. The worms died within days of their revival. But one of the female-only species began making offspring before she died. They reproduce asexually. Scientists want to determine how they can survive so long. They also hope to learn more about cryptobiosis.  

One of the study's co-authors told The Wall Street Journal: “This paper could make people consider this third condition between life and death.”

Photo from Shatilovich et al, 2023, PLOS Genetics.

Reflect: If you had the ability to take an unbelievably long nap and wake up in the future, what are some exciting things you would hope to see or learn about in the world?

Which of the following ideas is highlighted throughout the story? (Common Core RI.5.3; RI.6.3)
a. The end of the ice age.
b. The nematodes died within days of their revival.
c. The location of Siberian permafrost.
d. The survival of Siberian nematodes in permafrost for 46,000 years.
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