Clownfish may have been made famous through the popular film Finding Nemo, but probably only a few people realize that these charismatic orange-and-white fish offer huge potential for scientific research. Scientists can use them to answer a myriad of biological questions, from how larvae disperse in the open ocean to how coral reef fish will react to climate change. To help achieve these answers, researchers from the Okinawa Institute of Science and Technology Graduate University (OIST) have pieced together a comprehensive genome of the false clownfish (Amphiprion ocellaris). The study was published in G3 Genes|Genomes|Genetics.
"This genome, which is like the blueprint of the false clownfish, will be a very useful resource for scientists across biological fields," explained Dr. Marcela Herrera Sarrias, one of the two first authors of the study and Postdoctoral Scholar in OIST's Marine Eco-Evo-Devo Unit.
"We can use the false clownfish as a model species for studying ecology, evolution, adaption, development biology, and more," added Prof. Vincent Laudet, Principal Investigator of the Marine Eco-Evo-Devo Unit.
The false clownfish is found in both tropical and subtropical areas and relies on sea anemones, and thus the coral reef, for survival. Like many coral reef fish, it is expected that their populations will decline as coral reefs decrease in size due to climate change. This species looks very similar to orange clownfish—the true Nemo—but the two live in different areas. The false clownfish is found around Okinawa, Southeast Asia, the Philippines, and northwestern Australia while the orange clownfish is around northeastern Australia and some of the Pacific Islands. A comprehensive genome of the orange clownfish was published a few years ago so it was only fitting that, for comparative research, publication of the false clownfish's genome followed suit.
Although previous research has resulted in the genome of the false clownfish, this study produced by far the most high-quality version. The researchers highlighted that this was due to their version being at the scale of chromosomes.
The genome of the false clownfish is like the comprehensive instruction manual located in every one of its cells. It contains all the information needed for the operation of the fish. This instruction manual is divided into chapters—the chromosomes—and these are, in turn, divided into pages—the genes. Previously published genomes on the false clownfish comprised of scattered genes or chunks of genes, with little understanding of how they were arranged on the chromosome. In this new study, the genome is more fully assembled.
For this research, false clownfish were collected from Onna-son in Okinawa. The researchers extracted their DNA and RNA and used a sequencing technology to assemble the genomes at a chromosome scale. Then they could start answering some of the biological questions.
The two species of clownfish fit into the subfamily of anemonefish, which is made up of 28 fish species in total. The researchers decided to compare the two genomes to find out what genes the two species shared that might be missing from the other 26 species.
"Evolutionary speaking, the two clownfish species are separated from the other 26 species in the subfamily," said Dr. Taewoo Ryu, who led the project and is a Group Leader in OIST's Marine Climate Change Unit. "We wanted to find out what makes them special."
They uncovered 70 genes that were conserved in the genomes of the two species of clownfish, but not in the other 26 species. The other species still had some of the genes, but they were a little bit different. Furthermore, the researcher found that a subset of these genes is related to neurobiological function, so likely impacts the behavior and ecology of the two species of clownfish, in a way that makes them different from the rest of anemonefish.
"We've already started generating results using the published genome and there is a huge capacity for further climate change research on this species," concluded Prof. Tim Ravasi, senior author of the paper and Principal Investigator of the Marine Climate Change Unit. "This resource provides a new baseline to start other experiments."
More information:Taewoo Ryu et al, A chromosome-scale genome assembly of the false clownfish, Amphiprion ocellaris, G3 Genes|Genomes|Genetics (2022). DOI: 10.1093/g3journal/jkac074
Provided byOkinawa Institute of Science and Technology
Citation:New resource could provide clues on the past, present, and future of clownfish (2022, April 8)retrieved 10 April 2024from https://phys.org/news/2022-04-resource-clues-future-clownfish.html
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FAQs
New resource could provide clues on the past, present, and future of clownfish. Researchers have produced a comprehensive genome of the false clownfish, which could be used to answer a myriad of biological questions.
How have humans impacted clownfish? ›
Clownfish can be affected by many human impacts including pollution, artificial light, increase in water temperature, sedimentation due to deforestation, overfishing, direct collection for the aquarium trade, and the killing of anemones due to bleaching and overharvesting.
How are clownfish impacted by climate change? ›
Climate change and ocean acidification are threats to clownfish and their habitat. As seawater acidifies, it is harder for clownfish to correctly identify smells and sounds that usually help them navigate their habitat and recognize predators.
What are the characteristics of a clownfish? ›
The body shape of clownfish is perch-like—oval and laterally compressed with an interrupted lateral line. Their body color is a bright orange with three white bars, the middle with a forward bulge centrally. Thick black bands around the white bars separate the orange and white portions of the body.
What is the distribution of clownfish? ›
Geographical Distribution
The orange clownfish is native to the tropical waters of the Indo-Pacific region. Their distribution ranges from Northern Queensland, Australia to Melanesia, including New Britain, New Guinea, New Ireland, the Solomon Islands, and Vanuatu.
Will clownfish go extinct? ›
Although the future of clownfish and coral reefs is uncertain in the age of the climate crisis, it is not yet doomed. Clownfish are capable of living independently of anemones in the absence of predators, and are easily bred in captivity, hence their complete extinction is unlikely.
How did clownfish adapt to their environment? ›
Clownfish have adapted to life on the reef by developing a symbiotic relationship with the anemones. Clownfish are small and would be preyed upon by larger fish if they were not living within and protected by the stinging tentacles of the anemone.
How are clownfish affected by pollution? ›
Ocean acidification has also been shown to damage the smell and hearing of orange clownfish. When exposed to CO2 levels expected later this century, young clownfish become attracted to their predators and are unable to find their coral reef homes.
What are happening to clownfish? ›
Threats. Though clownfish are not highly threatened, their populations have decreased in some areas. This is because they make up 43% of the global marine ornamental trade, with 75% of these fish captured from the wild. This means, in exploited areas, there is reduced population density.
What causes clownfish to change gender? ›
Combining expert opinion with graphics to map their complex reproductive hierarchy, she explains that all clownfish have male and female reproductive organs. This means if a breeding female is lost, the dominant male can switch sex to replace her.
Clownfish are aggressively territorial of their anemone, and have a symbiotic relationship with it. They will protect their home from prying fish that like to eat anemone tentacles. The anemone venom protects the clownfish from their predators, and the clownfish are protected from anemone stings by their mucus.
Are blue clownfish real? ›
A true blue clownfish is still just a twinkle in clownfish breeders' eyes but every year we see just a little more of this unusual blue trait in an ever increasing number of domesticated clownfish.
What are 3 facts about clownfish? ›
Clownfish are found in coral reefs off the coast of Australia and South Asia. Clownfish have a symbiotic relationship (a relationship that benefits both species) with sea anemones (a sessile predator animal). Clownfish bodies have a mucus layer which is immune to the toxins the anemone produces to capture prey.
How do clownfish obtain resources? ›
Clownfish maintain a symbiotic relationship with anemones. These Hexacorallias (the subclass that anemones belong to) provide protection as well as food to the clowns, stinging unwanted visitors with their tentacles and catching debris and small critters that the clownfish can eat.
How have humans impacted fish? ›
Human fishing affects the size of the fish population, and over generations, the size of the fish. Scientists have found that when fisheries go after mostly large fish, they create evolutionary pressure that favors the survival of smaller fish. Eventually, intense pressure from fishing could lead to food supply issues.
Are clownfish scared of humans? ›
But it is precisely this fearlessness that is also revealed by the fact that they do not flee from humans. Their observations led the researchers to conclude that in regions with a high level of tourism, 'courageous' clownfish species such as the dusky anemonefish could displace more fearful species.
How does pollution affect clown fish? ›
Light pollution causes more harm than simply ruining the view during a starry night. A new study has found that clownfish can't raise any young when exposed to artificial light. The study observed 10 pairs of clownfish, with each pair in their own tank.
Why can't we eat clownfish? ›
It is believed that clownfish are saved by the anemones' poison by the thick mucus that coats their skin. It is believed that this mucus should not be eaten by humans, making many experts believe that we should avoid eating clownfish altogether.
