GigaScience Press

Nicole Nogoy

::: {#attachment_2978 .wp-caption .alignleft style="width: 222px"}
![Jellyfish
genomes](http://gigasciencejournal.com/blog/wp-content/uploads/2019/07/Fig-1.jpeg){.wp-image-2978
.size-full loading="lazy" decoding="async"
aria-describedby="caption-attachment-2978" width="212" height="499"
srcset="http://gigasciencejournal.com/blog/wp-content/uploads/2019/07/Fig-1.jpeg 212w, http://gigasciencejournal.com/blog/wp-content/uploads/2019/07/Fig-1-127x300.jpeg 127w"
sizes="(max-width: 212px) 100vw, 212px"}

Adapted from Ohdera A et al.
:::

[**Three jellyfish genomes are better than one**  
A new article in
]{style="font-weight: 400;"}*[GigaScience  ]{style="font-weight: 400;"}*[might
make you squirm if you plan to hit the beach this summer. The [published
work presents the draft genomes of three different jellyfish
species](https://doi.org/10.1093/gigascience/giz069). The international
group of researchers, lead by Joseph Ryan (University of Florida), chose
to examine jellyfish that present a range of physical traits and level
of toxicity (from minor annoyance to deadly) --- jellyfish kill more
people per year than the combined forces of sharks, stingrays, and sea
snakes. Their research identified a range of venom related genes,
providing the basis for exploring toxin gene evolution in these
fascinating animals.  ]{style="font-weight: 400;"}

[The three jellyfish species investigated are the deadly winged box
jellyfish  (]{style="font-weight: 400;"}*[Alatina
alata]{style="font-weight: 400;"}*[), the anatomically interesting
upside-down jellyfish (a true jellyfish:
]{style="font-weight: 400;"}*[Cassiopea
xamachana]{style="font-weight: 400;"}*[), and the stalked jellyfish
(]{style="font-weight: 400;"}*[Calvadosia
cruxmelitensis]{style="font-weight: 400;"}*[) so named for its stinging
organs forming a Maltese Cross pattern. The work here finally provides
genome sequences for all five lineages of the Medusozoa (a subphylum of
Cnidaria).]{style="font-weight: 400;"}

[Author Joseph Ryan said: *"With these new jellyfish genomes, for the
first time, we were able to compare gene content of all 5 classes of
cnidarians (Anthozoa, Hydrozoa, Cubozoa, Staurozoa, Scyphozoa). This
broad survey provides an important overview of genomic evolution in
cnidarians."*]{style="font-weight: 400;"}

[Compared with advances in toxicological research in venomous
vertebrates, toxicological research in cnidarians has been hampered by
the lack of extensive genetic information. The area of cnidarian venom
is of particular interest given that box jellyfish can be deadly to
beach goers: approximately 100 people die each year from their stings.
They are considered so dangerous that they are the only jellyfish to
have its own category in the US Weather
Report.  ]{style="font-weight: 400;"}

[Ryan notes: *"Box jellyfish are among the most venomous animals on the
planet and therefore their genomes are important resources for
developing antivenoms as well as potential drugs." He added, "Our survey
included a focused assessment of venom-related genes, providing insight
into the evolution of cnidarian venom." *]{style="font-weight: 400;"}

::: {#attachment_2968 .wp-caption .alignright style="width: 244px"}
![](http://gigasciencejournal.com/blog/wp-content/uploads/2019/07/Fascinated_by_Alatina.jpg){.wp-image-2968
.size-full loading="lazy" decoding="async"
aria-describedby="caption-attachment-2968" width="234" height="150"}

Allen Collins swimming with a box jellyfish
:::

[To investigate the toxins, the authors identified 117 putative venom
proteins, of which 9 were found only in cnidarians. The winged box
jellyfish genome was the only one to include a toxin gene called
]{style="font-weight: 400;"}*[CqTx]{style="font-weight: 400;"}*[. The
CqTx protein creates pores in the membranes of cells resulting in
hemolysis, the breaking down of red blood cells. Given that some box
jellyfish can stop someone's heart within 5 minutes, the identification
of this toxin in the winged box jellyfish adds another clue to the still
unclear mechanisms of how people die from a box jellyfish
sting.]{style="font-weight: 400;"}

[Comparisons of the genomes also revealed information about the
evolution of cnidarian venom. Gene loss and gene duplication both play
large roles in species evolution, and, as an example, the scientists'
analysis of another toxin gene,
]{style="font-weight: 400;"}*[CrTx]{style="font-weight: 400;"}*[, showed
both. The upside-down jellyfish contained a single
]{style="font-weight: 400;"}*[CrTx]{style="font-weight: 400;"}*[ gene,
the winged box jellyfish had]{style="font-weight: 400;"} [five copies of
this gene; and the stalked jellyfish had
none.]{style="font-weight: 400;"}

[Ryan expands on these findings, saying: *"Gene loss is an important
driver of evolutionary change. Having draft genomes allows for accurate
inferences of gene loss and for understanding the phenotypic
contribution of gene loss in these animals. Furthermore, these genomes
provide information about the order of genes in the genome, which in
some cases allow for independent verification of the identification of
hard-to-classify genes."*]{style="font-weight: 400;"}

[The addition of these three new jellyfish genomes to the [plant and
animal genome club](http://gigasciencejournal.com/blog/pag-asia-2019/)
means that there are now genome sequences available in all five classes
of cnidarians. Having access to this wealth of genetic information will
enable the exploration of the genetic underpinnings of this group's
incredibly diverse range of biological traits, which includes, but isn't
limited to, differences in life cycles, prey preferences, metamorphoses,
swimming behaviors, population blooms, sexual behaviors, environmental
stress reactions, cell type determination, and stinging capsule
development. Truly, within Cnidaria, researchers have a --- now unburied
--- treasure chest of information.]{style="font-weight: 400;"}

**Further Reading:  
**[Aki Ohdera, Cheryl L. Ames, Rebecca B. Dikow, Ehsan Kayal, Marta
Chiodin, Ben Busby, Sean La, Stacy Pirro, Allen G. Collins, Mónica
Medina, Joseph F. Ryan. Box, stalked and upside-down? Draft genomes from
diverse jellyfish (Cnidaria, Acraspeda) lineages:
]{style="font-weight: 400;"}*[Alatina
alata]{style="font-weight: 400;"}*[ (Cubozoa),
]{style="font-weight: 400;"}*[Calvadosia
cruxmelitensis]{style="font-weight: 400;"}*[ (Staurozoa), and
]{style="font-weight: 400;"}*[Cassiopea xamachana
]{style="font-weight: 400;"}*[(Scyphozoa).
]{style="font-weight: 400;"}*[GigaScience]{style="font-weight: 400;"}*[,
2019.
]{style="font-weight: 400;"}[[https://doi.org/10.1093/gigascience/giz069]{style="font-weight: 400;"}](https://doi.org/10.1093/gigascience/giz069)

The post [Genomic Warning Flag Just in Time for Beach Season: Jellyfish
Toxins](http://gigasciencejournal.com/blog/jellyfish-genomes/){rel="nofollow"}
appeared first on
[GigaBlog](http://gigasciencejournal.com/blog){rel="nofollow"}.


Adapted from Ohdera A et al.
<strong>
 Three jellyfish genomes are better than one
</strong>
A new article in
<em>
 GigaScience
</em>
might make you squirm if you plan to hit the beach this summer. The published work presents the draft genomes of three different jellyfish species.

Messaggi di Rogue Scholar

Genomic Warning Flag Just in Time for Beach Season: Jellyfish Toxins