With water temperatures dropping to minus 1.9 degrees Celsius in the Southern Ocean, the Antarctic spiny plunderfish (Harpagifer antarcticus) manages to survive extreme cold thanks to special antifreeze proteins that stop ice crystals from growing.
This research utilized the latest long-read technologies to decipher complex and repetitive regions of DNA. The study was led by the Senckenberg Research Institute and Natural History Museum in Frankfurt.
The team analyzed the maternal and paternal copies of the Harpagifer antarcticus genome separately for the first time. This method identified variations that might have otherwise gone undetected.
Dr. Iliana Bista, the study’s lead author, stated that this allows for a closer look at genetic variants. It provides new insights into the evolution of notothenioid fish.
Approximately 43 percent of the genome in the examined fish consists of repetitive DNA segments. LINE-L2 transposons are particularly common among these segments.
The team discovered evidence of adaptations in genes involved in defending against harmful oxidative processes, fat metabolism, the proper folding of proteins, and the maintenance of important cellular functions. High oxygen levels and low temperatures pose a constant challenge to cellular function in the icy waters of the Southern Ocean.
Survival in extreme cold depends on the interplay of various genetic and evolutionary mechanisms.
An international team has previously sequenced the genomes of 24 Antarctic fish species. This team included researchers from the British Antarctic Survey, the Wellcome Sanger Institute, the University of Cambridge, the University of Colorado, the Naturalis Biodiversity Center, and institutes in Norway and Switzerland.
The work builds upon an effort to understand notothenioids, a group of approximately 140 fish species that have developed specialized strategies to survive in the Antarctic.
That research was published in Nature Communications. It showed how icefish—a subgroup of notothenioids—lost their oxygen-binding haemoglobin proteins entirely, resulting in white blood.
Professor Richard Durbin, senior author of the research, noted that such advances in genomics are revolutionizing the ability to understand biodiversity across the world.
The findings were published in Genome Biology in 2026. They show that survival in extreme cold depends on the interplay of various genetic and evolutionary adaptation mechanisms.
“Our study illustrates how genetic changes help Antarctic fishes to survive even under the extreme conditions of the Southern Ocean,” said Dr Iliana Bista, the study's last author from the Senckenberg Research Institute and Natural History Museum in Frankfurt.
