South American Lungfish Genome Identified as Largest Known
Researchers sequenced the massive South American lungfish genome, which contains 91 billion base pairs.
Updated on Oct. 30, 2026 in Life Sciences
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A 2024 study published in Nature identified the South American lungfish genome as the largest in the animal kingdom. This genetic map contains 91 billion base pairs, making it 30 times larger than the human genome.
Why it matters
The massive genome size is attributed to a low content of piRNAs, which normally restrict the movement and proliferation of repetitive DNA sequences known as transposons. Understanding this mechanism offers insights into how complex genomes expand over evolutionary time.
The South American lungfish genome contains 91 billion base pairs, with 90 percent of its structure composed of repetitive DNA. Researchers found the genome expanded at a rate equivalent to one human genome every 10 million years.
The players
Nature
This is a prominent multidisciplinary scientific journal that publishes peer-reviewed research across all areas of science and technology.
The details
Transposons, which are genetic elements that change positions within a genome, drove this rapid expansion over the past 100 million years. Comparatively, other species have significantly smaller genomes, such as the West African lungfish at 40 billion base pairs and the Antarctic krill at 48 billion base pairs.
Timeline
380 million to 360 million years ago lobe-finned fish conquered land during the late Devonian period.
The South American lungfish genome expanded rapidly over the past 100 million years.
A study regarding ecological constraints and genome size was published in 2019.
A study on lungfish genome sequencing was published in Nature in 2024.
The Big Picture
The sequencing of the South American lungfish genome provides a significant new data point relative to the Human Genome Project, establishing a new ceiling for genomic size in the animal kingdom. This finding challenges prior assumptions about the limits of repetitive DNA accumulation in vertebrate species.
The discovery of how transposons influence genome size could advance medical research into genetic stability and DNA repair mechanisms. While not directly altering current consumer products, these findings enhance the fundamental scientific knowledge used in synthetic biology and genetic engineering.
The takeaway
The study highlights how repetitive DNA sequences can drive massive genetic expansion when regulatory mechanisms are minimal. These findings emphasize that genome size does not necessarily correlate with organismal complexity.
Further reading
For more context on ongoing genomic research, explore the Life Sciences section.
Source note: This article includes information reported by Discover Magazine.
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