Antarctic blackfin icefish genome reveals adaptations to extreme environments

Bo Mi Kim, Angel Amores, Seunghyun Kang, Do Hwan Ahn, Jin Hyoung Kim, Il Chan Kim, Jun Hyuck Lee, Sung Gu Lee, Hyoungseok Lee, Jungeun Lee, Han Woo Kim, Thomas Desvignes, Peter Batzel, Jason Sydes, Tom Titus, Catherine A. Wilson, Julian M. Catchen, Wesley C. Warren, Manfred Schartl, H. William DetrichJohn H. Postlethwait, Hyun Park

Research output: Contribution to journalArticlepeer-review

Abstract

Icefishes (suborder Notothenioidei; family Channichthyidae) are the only vertebrates that lack functional haemoglobin genes and red blood cells. Here, we report a high-quality genome assembly and linkage map for the Antarctic blackfin icefish Chaenocephalus aceratus, highlighting evolved genomic features for its unique physiology. Phylogenomic analysis revealed that Antarctic fish of the teleost suborder Notothenioidei, including icefishes, diverged from the stickleback lineage about 77 million years ago and subsequently evolved cold-adapted phenotypes as the Southern Ocean cooled to sub-zero temperatures. Our results show that genes involved in protection from ice damage, including genes encoding antifreeze glycoprotein and zona pellucida proteins, are highly expanded in the icefish genome. Furthermore, genes that encode enzymes that help to control cellular redox state, including members of the sod3 and nqo1 gene families, are expanded, probably as evolutionary adaptations to the relatively high concentration of oxygen dissolved in cold Antarctic waters. In contrast, some crucial regulators of circadian homeostasis (cry and per genes) are absent from the icefish genome, suggesting compromised control of biological rhythms in the polar light environment. The availability of the icefish genome sequence will accelerate our understanding of adaptation to extreme Antarctic environments.

Original languageEnglish (US)
Pages (from-to)469-478
Number of pages10
JournalNature Ecology and Evolution
Volume3
Issue number3
DOIs
StatePublished - Mar 1 2019

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Ecology

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