The genome of the giant Nomura\u2019s jellyfish sheds light on the early evolution of active predation

Youngjune Bhak,Yeonsu Jeon,Yun Sung Cho,Marc W. Kirschner,Amir Karger,Seonock Woo,Kyoungsoon Shin,Jae‐Chun Ryu ,Seung Gu Park,Jessica A. Weber,Seungshic Yum,Nayoung Lee,Hak-Min Kim,Nayun Lee,Sungwon Jeon,Hyung-Soon Yim,Jung-Hyun Lee,Jeremy S. Edwards,Andrea Manica,Oksung Chung,Y. Jo ,Jong Bhak,Victor Luria

doi:10.1186/s12915-019-0643-7

Abstract

BackgroundUnique among cnidarians, jellyfish have remarkable morphological and biochemical innovations that allow them to actively hunt in the water column and were some of the first animals to become free-swimming. The class Scyphozoa, or true jellyfish, are characterized by a predominant medusa life-stage consisting of a bell and venomous tentacles used for hunting and defense, as well as using pulsed jet propulsion for mobility. Here, we present the genome of the giant Nomura’s jellyfish (Nemopilema nomurai) to understand the genetic basis of these key innovations.ResultsWe sequenced the genome and transcriptomes of the bell and tentacles of the giant Nomura’s jellyfish as well as transcriptomes across tissues and developmental stages of the Sanderia malayensis jellyfish. Analyses of the Nemopilema and other cnidarian genomes revealed adaptations associated with swimming, marked by codon bias in muscle contraction and expansion of neurotransmitter genes, along with expanded Myosin type II family and venom domains, possibly contributing to jellyfish mobility and active predation. We also identified gene family expansions of Wnt and posterior Hox genes and discovered the important role of retinoic acid signaling in this ancient lineage of metazoans, which together may be related to the unique jellyfish body plan (medusa formation).ConclusionsTaken together, the Nemopilema jellyfish genome and transcriptomes genetically confirm their unique morphological and physiological traits, which may have contributed to the success of jellyfish as early multi-cellular predators.

Highlights

Unique among cnidarians, jellyfish have remarkable morphological and biochemical innovations that allow them to actively hunt in the water column and were some of the first animals to become free-swimming
The class Scyphozoa, or true jellyfish, are characterized by a predominant medusa life-stage consisting of a bell and venomous tentacles used for hunting and defense [3]
Jellyfish genome assembly and annotation Here, we present the first de novo genome assembly of the Nomura’s jellyfish (Nemopilema nomurai; Fig. 1b)

Summary

Introduction

Jellyfish have remarkable morphological and biochemical innovations that allow them to actively hunt in the water column and were some of the first animals to become free-swimming. The class Scyphozoa, or true jellyfish, are characterized by a predominant medusa life-stage consisting of a bell and venomous tentacles used for hunting and defense, as well as using pulsed jet propulsion for mobility. We present the genome of the giant Nomura’s jellyfish (Nemopilema nomurai) to understand the genetic basis of these key innovations. Cnidarians, including jellyfish and their predominantly sessile relatives the coral, sea anemone, and hydra, first appeared in the Precambrian Era and are key members of aquatic ecosystems worldwide (Fig. 1a) [1]. Between 500 and 700 million years ago, jellyfish developed novel physiological traits that allowed them to become.

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Conclusion