2026-03-24 ノースウェスタン大学
The first study to sequence the snow fly’s genome shows the insects use a surprising combination of strategies to survive in freezing conditions. The findings shed light on how life has adapted to survive extreme environments and could inform new strategies for protecting cells, tissues and materials from cold damage. Photo credit Håkan Söderholm.
＜関連情報＞
- https://news.northwestern.edu/stories/2026/03/some-like-it-cold-snow-flies-create-their-own-heat-to-avoid-freezing
- https://www.cell.com/current-biology/fulltext/S0960-9822(26)00247-2
分子レベルと生理学的適応の協調により、ユキバエChionea alexandrianaは氷点下の温度でも活動できる Coordinated molecular and physiological adaptations enable activity at sub-freezing temperatures in the snow fly Chionea alexandriana
Matthew Capek ∙ Richard Suhendra ∙ Zhenzhen Yang ∙ … ∙ Alessia Para ∙ Marcus Stensmyr ∙ Marco Gallio
Current Biology Published:March 24, 2026
DOI:https://doi.org/10.1016/j.cub.2026.02.060
Highlights
- Snow flies (Chionea) are wingless crane flies often found roaming on snow
- Comparative genomics finds gene-family expansions in the Chionea lineage
- Experiments show that Chionea can produce heat (∼1°C), likely from mitochondria
- Antifreeze proteins and reduced ROS sensitivity also contribute to cold tolerance
Summary
Snow flies (Chionea) are wingless crane flies uniquely adapted to extreme cold environments. Adults remain active throughout winter and move rapidly across the snow, even at temperatures below freezing. To investigate the molecular adaptations that make this possible, we sequenced and annotated the genome of Chionea alexandriana and compared it with related species and with the cold-adapted midge, Belgica antarctica. We identify ∼20 lineage-specific and 8 shared gene-family expansions in Chionea and Belgica, corresponding to functions ranging from sensory signaling to DNA packaging. The Chionea genome encodes antifreeze proteins (AFPs), and we show that transgenic expression of an AFP in Drosophila is sufficient to protect larvae from freezing-induced death. Our results also reveal a coordinated expansion of mitochondrial and peroxisomal enzymes, as well as regulators of peroxisome-mitochondria interactions involved in mammalian thermogenesis. Consistent with this, direct measurements reveal that snow flies produce brief bursts of endogenous heat in response to cooling at sub-freezing temperatures, indicating active thermogenic capacity. Finally, our results demonstrate that Chionea has evolved mechanisms to cope with high levels of reactive oxygen species (ROS), a byproduct of mitochondrial activity and a hallmark of cold exposure. These include a 35-fold increase in the threshold for ROS activation of the insect nociceptor TRPA1, as measured in vitro by patch-clamp electrophysiology. Together, our results reveal specific molecular adaptations that enable the snow fly to thrive in extreme cold conditions and suggest that selective gene-family expansion may represent a key mechanism for the adaptation of insects to cold environments.
