Scientists Discover First Animal That Doesn't Need Oxygen

The discovery upturns our understanding of how alien life could exist.
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For generations, we’ve lived with the knowledge that oxygen is a key element of life, and without it, life would not exist. That assumption has just been overturned with the recent discovery of a multicellular animal that doesn’t breathe oxygen for life. 

Scientists found out that a salmon parasite called Henneguya salminicola—a distant relative of the jellyfish and the sea anemone—lacks mitochondria, the powerhouse of a cell. The mitochondria is the very reason why animals breathe oxygen—to metabolize and break down nutrients using oxygen. The process is called aerobic respiration, which occurs in all animals, or so we thought. 

The study was published in the scientific journal Proceedings of the National Academy of Sciences or PNAS. According to the authors of the study, the salmon parasites lost their mitochondria that were replaced with a similar organelle that utilizes hydrogen instead of oxygen

Hydrogen is the most common element in the universe. Following the discovery of the salmon parasite’s unique biological processes, we could surmise that alien life could also thrive elsewhere even without oxygen. 

When scientists sequenced the genes of the salmon parasite, they discovered the organism had no mitochondrial genome, which is responsible for aerobic respiration that uses oxygen. 

“We speculate that the loss of the mitochondrial genome in H. salminicola was driven by low-oxygen environments in both of its hosts,” said the scientists. 

Although there are many organisms that do not require oxygen to thrive (fungi, bacteria, protozoa), this is the first time a full-fledged multicellular animal was observed to have no use for oxygen. 


“Our discovery confirms that adaptation to an anaerobic environment is not unique to single-celled eukaryotes, but has also evolved in a multicellular, parasitic animal,” conclude the scientists.

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Mario Alvaro Limos
Features Editor, Esquire Philippines
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