Fascinating Secrets Clownfish Earn Their Stripes

 

According to a P N A S study, clownfish's distinctive white stripes form at different rates depending on their sea anemone hosts. 

Thyroid hormones, which are crucial for metamorphosis, control the speed at which the white bars form. Thyroid hormone levels are higher in clownfish that live in the giant carpet anemone compared to clownfish that live in the magnificent sea anemone. Clownfish that live in the giant carpet anemone also show increased activity of duo x, a gene involved in the formation of thyroid hormones. Charismatic clownfish, the coral reef fish made famous by the movie Finding Nemo Scientists call these stripes bars because they appear as clownfish, grow from larvae to adults through a process called metamorphosis. However, the process by which these distinct patterns are formed has been a mystery for a long time. 

Now, a new study has found that the clownfish's sea anemone species influences how quickly these white bars form. Through changes in the activity of a gene called duo x, the researchers also discovered that thyroid hormones, which are important for metamorphosis, control how quickly their stripes appear. 

According to senior author Professor Vincent Lauder, who directs the Marine E C O E V O D E V O Unit at the Okinawa Institute of Science and Technology Graduate University (O I S T), "metamorphosis is an important process for clownfish because it changes both their appearance and the environment in which they live". Clownfish larvae leave life in the open ocean and settle in the reef. We can answer questions about how sea anemones adapt to different environments and how they might be affected by other environmental pressures, like climate change, if we know how metamorphosis changes depending on the host. 

In the review, distributed on May 24th, 2021, in P N A S, a group of scientists from the Middle for Island Exploration and Ecological Observatory (C R I O B E) in France previously studied the clownfish species

Clownfish in coral reefs were the subject of research at the Sorbonne University in Paris. Clownfish that were young and lived in huge carpet anemones did not develop their adult white bars as quickly as clownfish that lived in sea anemones. White bars in clownfish developed more quickly when thyroid hormones were given at higher doses

Clownfish from the giant carpet anemone had significantly higher levels of thyroid hormones than the magnificent sea anemone. Thyroid hormone is made in large part by one of the genes, duo x, which makes the protein dual oxidase

Duo X's role in the development of pigment cells was confirmed by additional experiments carried out in collaboration with Professor David P. Ricky from the University of Virginia in the United States. According to the findings of the study, pigment cell development is slowed in mutant zebrafish caused by the inactivation of the duo X gene. 

The findings, taken as a whole, suggest that clownfish living in the giant carpet anemone have higher levels of thyroid hormones as a result of the increased activity of duo x. As a result, white bars form at a faster rate because pigment cells develop more quickly. 

The ecological reason for this variation in the rate of white bar formation is one more question that the research raises for the scientists to answer. 

The researchers speculated that this might be because thyroid hormone levels rise in response to stress, making the giant carpet anemone more toxic. 

Prof L A U D E T stated, "We're beginning to delve into some possible explanations here at O I S T". We believe that these modifications to the formation of white bars are only the tip of the iceberg, and that there are numerous other differences that assist the clownfish in adapting to the two distinct hosts of sea anemones