What secret weapons are hidden in the genome of the invading jellyfish |? BMC Biology

Title: The genome of the giant Nomura's jellyfish shedds light on the early evolution of active predation
Journal:
Hak-Min Kim†, Jessica A. Weber†, Nayoung Lee†, Seung Gu Park, Yun Sung Cho, Youngjune Bhak, Nayun Lee, Yeonsu Jeon, Sungwon Jeon, Victor Luria, Amir Karger, Marc W. Kirschner, Ye Jin Jo, Seonock Woo, Kyoungsoon Shin, Oksung Chung, Jae-R Chunyu, Hyung-Hyun , Jeremy S. Edwards, Andrea Manica, Jong Bhak and Seungshic Yum
published: 2019/03/29
Digital ID: 10.1186/s12915-29 019-0643-7
Original Link:
WeChat Link:
Jellyfish's structure may seem simple, but it can help us understand how complex animal life evolved in hundreds of millions of years. In a follow-up
, researchers who published a paper on the project shared their findings in the genome of the giant Nomuras jellyfish.jellyfish belong to cnidaria, which also contains corals,anemones, etc. Hedgehogs were one of the earliest branches of the post-animal genealogy. The group experienced significant diversity changes about 500 million years ago, with hedgehogs as sisters of symmetrical animals on both sides, including 99 percent of living animals and humans, and studying them could shed light on major events in the evolution of complex animal life.
the symmetrical animals on both sides survived on land and at sea, the hedgehogs still survive in the water.
is arguably the most active of the hedgehogs: they
compared to other hedgehogs, and jellyfish's unique lifestyle reflects their choice of different genes and mutations over millions of years. For example, in this article published in BMC Biology, we found that jellyfish have genes associated with good muscle and neuron signaling. When swimming vertically or horizontally, jellyfish have evolved the ability to quickly control osmosis pressure to cope with different water concentrations.
best way to understand and define jellyfish is to compare the jellyfish genome with the genomes of other hedgehogs that contain enough genes and proteins. Because jellyfish and other hedgehogs, such as waterand corals, are so far apart in evolutionary relationships, it is easy to compare them on esotypes, but it is difficult to pinpoint the genetic variation of jellyfish. Fortunately, a great deal of research has been published on the genomics of hedgehogs, and we have detected enough specific gene, pathology, and protein domains to help us redefine jellyfish from a genetic perspective.
to compare jellyfish genomes, we need to find some jellyfish as subjects, " he said. We were lucky enough to find many huge jellyfish floating on South Korea's warm southern coast. These giant jellyfish, which are up to 2 meters wide and weigh 200 kilograms, are called pre-Vietnam jellyfish. In Japan, they are sometimes considered a food, but they are dangerous and can sometimes cause death and have long been rejected by South Korean fishermen. Traces of jellyfish have also been found in China's Yellow Sea and south China Sea, which have spread to the South Pacific. Perhaps because of global warming and overfishing of swordfish and tuna, Jellyfish are now breeding rapidly in South Korean waters and in the Sea of Japan.
we captured one of them and sequenced its genome and transcription group, and then compared the results with the genomes of other hedgehogs and symmetrical animals on both sides. The first step is genome assembly: the results of Illumina's short DNA fragment sequencing and PacBio's long DNA fragment sequencing results are assembled. They were then compared with the genomes of seven other , anemones and aquatic animals to identify their genetic differences.
, seven genomic studies of hedgehogs have been published, including pre-vietnamese jellyfish. Jellyfish have great differences in morphology, so we focus on using differences in genetic levels to illustrate jellyfish's physical ability.
jellyfish belong to the jellyfish, its genome size is 213 Mbp, for hedgehogs of moderate size. But compared to 3 Gbp in humans, this is a very small genome. Nevertheless, it has almost the same number of genes as a human (19,525). Since the HOX gene can have an effect on body shape, we analyzed the different recombination forms of the HOX gene to study the gene. Jellyfish are unique in hedgehogs because of their unique head and tail. Although we have observed the unique combination of HOX genes in jellyfish genomes, there is no research evidence linking HOX gene expression and downstream development pathways to the specific morphological characteristics of jellyfish.
From the genome comparison, we also found that jellyfish's genome seems to have adapted to the "chemical stability of cells" and "sodium ion transport" function, which other hedgehogs do not have. As mentioned earlier, this behavior makes sense and guarantees that they can swim vertically and horizontally in the water over long distances to catch prey.
jellyfish are not really smart, and they don't have brains, eyes or other sensory organs, they only have tiny sensory structures that exist in the tentacles. These structures are called "tentacles". Jellyfish use their tentacles and nervous systems (neural networks) to identify light sources and odors. Compared to symmetrical animals on both sides, such as humans, fruit flies, and zebrafish, we found that the number of gene families associated with sensory subjects decreased significantly in jellyfish, a phenomenon that is also found in other hedgehogs.
jellyfish use their tentacles to hunt. They also have very strong defenses. To spread their infamous stench, jellyfish evolved a special structure: hedgehog sacs. Their tentacles contain thousands of hedgehog sacs from thousands of hedgehogs that produce thousands of tiny doses of venom when stimulated. Typical jellyfish venoms include phospholipidase A2 and metal protease, and we found that these venom-related protein domains and genes are beneficial to active predators.
in summary, at least one jellyfish has been observed in its body structure (head and tentacle), chemical penetration adaptability (solution permeation pressure) and body coordination (jet propulsion of the body forward) to retain the characteristics left over from evolution.
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, 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.We 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 ofWnt 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).Taken 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.is an open access journal publishing outstanding research in all areas of biology, with a publication policy that combines selection for broad interest and importance with a commitment to serving authors well.
(Source: Science.com)