Hans Zauner

**We start the new year with news from the deep, [published in
*GigaScience*](https://doi.org/10.1093/gigascience/giad107): The genome
of a sea cucumber, collected at a depth of 2400 m during a submarine
trip to a hydrothermal vent, helps scientists to understand how marine
animals can survive in extreme conditions.**

Hydrothermal vents are an unlikely environment for animals to flourish.
Temperatures change dramatically, from really cold to boiling hot, and
the chemistry near an active vent is something else altogether: acidic
pH, sulfur and methane are the typical combination. Not to mention the
high hydrostatic pressure and the darkness of the deep sea.

The research team of [Haibin Zhang from the Institute of Deep-sea
Science 
and Engineering (Chinese Academy of
Sciences)](https://people.ucas.edu.cn/~hzhang123?language=en) have now
sequenced the full genome of a particularly unusual inhabitant of the
hydrothermal vent environment: the sea cucumber *Chiridota heheva.*

<figure class="wp-block-image size-large is-resized">
<img
src="http://gigasciencejournal.com/blog/wp-content/uploads/2024/01/sea-cucumber-1024x571.png"
class="wp-image-5587" loading="lazy" decoding="async"
srcset="http://gigasciencejournal.com/blog/wp-content/uploads/2024/01/sea-cucumber-1024x571.png 1024w, http://gigasciencejournal.com/blog/wp-content/uploads/2024/01/sea-cucumber-300x167.png 300w, http://gigasciencejournal.com/blog/wp-content/uploads/2024/01/sea-cucumber-768x428.png 768w, http://gigasciencejournal.com/blog/wp-content/uploads/2024/01/sea-cucumber.png 1536w"
sizes="(max-width: 643px) 100vw, 643px" width="643" height="358"
alt="Sampling a sea cucumber at the Kairei vent field of the Indian Ocean" />
<figcaption>Sampling a sea cucumber at the Kairei vent field of the
Indian Ocean. Credit: IDSSE Deep-sea Scientific Research Image and Video
Database.</figcaption>
</figure>

 

### Unique life forms {#unique-life-forms .wp-block-heading}

Organisms found at [hydrothermal
vents](https://oceanservice.noaa.gov/facts/vents.html) are among the
most unique life forms on the planet. They evolved special adaptations
to survive and procreate under these harsh conditions. For example, many
microbes employ special metabolic functions to deal with the abundance
of sulfur and iron, and to withstand the enormous heat near the vent. In
addition to microbes, there are even multicellular and higher order
organisms that have adapted to the hydrothermal vent conditions,
including various species of worms, snails, crabs and shrimp.

In 2019, a Chinese deep sea expedition with the manned research
submarine "Shenhaiyongshi" collected a specimen of the sea cucumber *C.
hehevae* at the bottom of the Indian Ocean, at the [Kairei vent
field](https://vents-data.interridge.org/ventfield/kairei-field) at a
depth of 2,428 meters. The water around the Kairei vent is rich in
dissolved iron, adding to the already harsh conditions.

Sea cucumbers are echinoderms, and as such related to sea urchins and
[sea
stars](http://gigasciencejournal.com/blog/brooding-brittle-star-babies-qa-jannes-landschoff/)
-- a group of animals with highly unusual body plans. They are found on
sea floors all over the world, where they devour detritus and use their
tentacle to explore the sediment. While other high-quality genomes of
sea cucumbers are available, the work now presented in *GigaScience* is
the first high-quality genome of a sea cucumber specimen collected at a
hydrothermal vent.

### Expanded sea cucumber gene families {#expanded-sea-cucumber-gene-families .wp-block-heading}

Initial comparative genome analyses indicate that several gene families
are expanded in this sea cucumber, meaning that the species has a higher
repertoire of specific sets of genes than related species.

Specifically, gene family analyses revealed that 450 gene families
expanded and 6 contracted in *C. heheva*, and that some of the expanded
gene families have roles in iron binding and transport -- indications
that these genomic changes may be interpreted as adaptations to the
iron-rich environment.

Another group of genes that show indication of adaptation are genes
related to DNA repair, and again this can be interpreted as adaptation
to the harsh environment. While the details will need to be studied in
more detail, the genomic data that's now available are a valuable
resource for further studies on both, sea cucumbers and the unique vent
fauna.

 

## **References:**

**A high-quality chromosomal genome assembly of the sea cucumber
*Chiridota heheva* and its hydrothermal adaptation** 
Yujin Pu, Yang Zhou, Jun Liu, Haibin Zhang 
*GigaScience*, 2024, giad107
<https://doi.org/10.1093/gigascience/giad107>

**Supporting data for "A High-Quality Chromosomal Genome Assembly of the
Sea Cucumber *Chiridota heheva* and Its Hydrothermal Adaptation." 
**Yujin Pu, Yang Zhou, Jun Liu, Haibin Zhang 
GigaScience Database. 2023 <https://doi.org/10.5524/102481> 

 

 

 

 

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We start the new year with news from the deep, published in
 
 GigaScience
 
 : The genome of a sea cucumber, collected at a depth of 2400 m during a submarine trip to a hydrothermal vent, helps scientists to understand how marine animals can survive in extreme conditions.

Hydrothermal vents are an unlikely environment for animals to flourish.

Messaggi di Rogue Scholar

Some sea cucumbers like it hot