2023-07-27 マックス・プランク研究所
◆研究者は、氷河期後期から約46,000年前からクリプトビオシスで生きていたと推定される線虫を発見しました。彼らは新種であることを明らかにし、「Panagrolaimus kolymaensis」と名付けました。
◆ドレスデンの研究者たちは、この線虫とCaenorhabditis elegansの遺伝子を比較し、似たような遺伝子がクリプトビオシスに関与していることを発見しました。また、これらの線虫は弱い脱水処理を受けることでクリプトビオシスに備え、氷点下80度の温度でも生存する能力を持つことがわかりました。
◆この研究は、進化過程を理解する上で重要であり、地球温暖化に対するより良い保護戦略の開発にも寄与する可能性があります。
<関連情報>
- https://www.mpg.de/20673509/0726-mozg-genome-analysis-of-46-000-year-old-roundworm-from-siberian-permafrost-reveals-novel-species-151300-x
- https://journals.plos.org/plosgenetics/article
シベリアの永久凍土に生息する新種の線虫は線虫のダウアー幼虫とクリプトバイオティクス生存の適応メカニズムを共有している A novel nematode species from the Siberian permafrost shares adaptive mechanisms for cryptobiotic survival with C. elegans dauer larva
Anastasia Shatilovich ,Vamshidhar R. Gade ,Martin Pippel,Tarja T. Hoffmeyer,Alexei V. Tchesunov,Lewis Stevens,Sylke Winkler,Graham M. Hughes,Sofia Traikov,Michael Hiller,Elizaveta Rivkina,Philipp H. Schiffer ,Eugene W. Myers,Teymuras V. Kurzchalia
PLOS Genetics Published: July 27, 2023
DOI:https://doi.org/10.1371/journal.pgen.1010798
Abstract
Some organisms in nature have developed the ability to enter a state of suspended metabolism called cryptobiosis when environmental conditions are unfavorable. This state-transition requires execution of a combination of genetic and biochemical pathways that enable the organism to survive for prolonged periods. Recently, nematode individuals have been reanimated from Siberian permafrost after remaining in cryptobiosis. Preliminary analysis indicates that these nematodes belong to the genera Panagrolaimus and Plectus. Here, we present precise radiocarbon dating indicating that the Panagrolaimus individuals have remained in cryptobiosis since the late Pleistocene (~46,000 years). Phylogenetic inference based on our genome assembly and a detailed morphological analysis demonstrate that they belong to an undescribed species, which we named Panagrolaimus kolymaensis. Comparative genome analysis revealed that the molecular toolkit for cryptobiosis in P. kolymaensis and in C. elegans is partly orthologous. We show that biochemical mechanisms employed by these two species to survive desiccation and freezing under laboratory conditions are similar. Our experimental evidence also reveals that C. elegans dauer larvae can remain viable for longer periods in suspended animation than previously reported. Altogether, our findings demonstrate that nematodes evolved mechanisms potentially allowing them to suspend life over geological time scales.
Author summary
Survival in extreme environments for prolonged periods is a challenge that only a few organisms, are capable of. It is not well understood, which molecular and biochemical pathways are utilized by such cryptobiotic organisms, and how long they might suspend life. Here, we show that a soil nematode Panagrolaimus kolymaensis, suspended life for 46,000 years in the Siberian permafrost. Through comparative analysis, we find that P. kolymaensis and model organism C. elegans utilize similar adaptive mechanisms to survive harsh environmental conditions for prolonged periods. Our findings here are important for the understanding of evolutionary processes because generation times could be stretched from days to millennia, and long-term survival of individuals of species can lead to the refoundation of otherwise extinct lineages.
