Morphology and genome of a snailfish from the Mariana Trench provide insights into deep-sea adaptation

• Published in: Nature ecology & evolution Vol. 3; no. 5; pp. 823 - 833
• Main Authors: Wang, Kun, Shen, Yanjun, Yang, Yongzhi, Gan, Xiaoni, Liu, Guichun, Hu, Kuang, Li, Yongxin, Gao, Zhaoming, Zhu, Li, Yan, Guoyong, He, Lisheng, Shan, Xiujuan, Yang, Liandong, Lu, Suxiang, Zeng, Honghui, Pan, Xiangyu, Liu, Chang, Yuan, Yuan, Feng, Chenguang, Xu, Wenjie, Zhu, Chenglong, Xiao, Wuhan, Dong, Yang, Wang, Wen, Qiu, Qiang, He, Shunping
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01-05-2019; Nature Publishing Group
• Subjects: 45/23; 45/91; 631/181/735; 631/208/212; 631/601/1737; 631/601/2722; 64/116; 704/829/826; Acclimatization; Adaptation; Adaptation, Physiological; Animals; Biological and Physical Anthropology; Biomedical and Life Sciences; Bones; Calcification; Cartilage; Cell membranes; Darkness; Deep sea; Ecology; Evolutionary Biology; Fluidity; Frameshift mutation; Gene sequencing; Genetic analysis; Genetic diversity; Genomes; Genomic analysis; Hsp90 protein; Life Sciences; Membrane fluidity; Membrane proteins; Molecular evolution; Morphology; Mutation; Osteocalcin; Paleontology; Phylogeny; Physiology; Protein transport; Proteins; Trimethylamine; Vertebrates; Zoology
• ISSN: 2397-334X; 2397-334X
• DOI: 10.1038/s41559-019-0864-8

It is largely unknown how living organisms—especially vertebrates—survive and thrive in the coldness, darkness and high pressures of the hadal zone. Here, we describe the unique morphology and genome of
Pseudoliparis swirei
—a recently described snailfish species living below a depth of 6,000 m in the Mariana Trench. Unlike closely related shallow sea species,
P. swirei
has transparent, unpigmented skin and scales, thin and incompletely ossified bones, an inflated stomach and a non-closed skull. Phylogenetic analyses show that
P. swirei
diverged from a close relative living near the sea surface about 20 million years ago and has abundant genetic diversity. Genomic analyses reveal that: (1) the bone Gla protein (
bglap
) gene has a frameshift mutation that may cause early termination of cartilage calcification; (2) cell membrane fluidity and transport protein activity in
P. swirei
may have been enhanced by changes in protein sequences and gene expansion; and (3) the stability of its proteins may have been increased by critical mutations in the trimethylamine
N
-oxide-synthesizing enzyme and hsp90 chaperone protein. Our results provide insights into the morphological, physiological and molecular evolution of hadal vertebrates.
Analysing the genome of a snailfish from the Mariana Trench, the authors show genetic changes associated with unique morphological and physiological adaptations to life in the hadal zone.