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New discovery may redefine classifications in the animal kingdom

Close cousin of jellyfish evolved into a microscopic parasite that lives in fish, study shows

Date:
November 18, 2015
Source:
American Friends of Tel Aviv University
Summary:
A close cousin of the jellyfish has evolved over time into a microscopic parasite, new research shows. The finding represents the first case of extreme evolutionary degeneration of an animal body.
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Researchers have found that a close cousin of the jellyfish has evolved over time into a microscopic parasite. The finding represents the first case of extreme evolutionary degeneration of an animal body.
Credit: © Aris Kamarotos / Fotolia

Children are taught that all living organisms -- from animals, plants, and fungi to bacteria and single-celled organisms -- belong to specifically different categories of organic life. A new discovery by Tel Aviv University researchers and international collaborators is poised to redefine the very criteria used to define and classify these animals.

Researchers have found that a close cousin of the jellyfish has evolved over time into a microscopic parasite. The finding represents the first case of extreme evolutionary degeneration of an animal body.

The research was led by Prof. Dorothée Huchon of TAU's Department of Zoology and Prof. Paulyn Cartwright of the University of Kansas, in collaboration with Prof. Arik Diamant of Israel's National Center for Mariculture and Prof. Hervé Philippe of the Centre for Biodiversity Theory and Modelling, CNRS, France. It was published in the Proceedings of the National Academy of Sciences.

What makes a myxozoan

The international research used genome sequencing to find that myxozoans, a diverse group of microscopic parasites that infect invertebrate and vertebrate hosts, are actually are highly degenerated cnidarians -- the category or phylum that includes jellyfish, corals and sea anemones.

"These micro-jellyfish expand our basic understanding of what makes up an animal," said Prof. Huchon. "What's more, the confirmation that myxozoans are cnidarians demands the re-classification of myxozoa into the phylum cnidaria."

Despite the radical changes in its body structure and genome over millions of years, the myxozoa have retained some of the basic characteristics of the jellyfish, including the essential genes to produce the jellyfish stinger.

"The myxozoa are microscopic -- only a few cells measuring 10 to 20 microns across -- and therefore biologists assumed that they were single-celled organisms," said Prof. Huchon. "But when we sequenced their DNA, we discovered the genome of an extremely strange macroscopic marine animal."

Real-world applications

The discovery of the dramatic change from macroscopic marine animal to microscopic parasite is interesting on its own, but it may also have commercial applications, as myxozoa commonly plague commercial fish stock such as trout and salmon.

"Some myxozoa cause a neurological problem in salmon called 'whirling disease,'" said Prof. Huchon. "These fish parasites cause tremendous damage to the fish industry, and unfortunately there is no general treatment against them. We hope that our data will lead to a better understanding of the biology of these organisms and the development of more effective drugs to fight against myxozoa."


Story Source:

Materials provided by American Friends of Tel Aviv University. Note: Content may be edited for style and length.


Journal Reference:

  1. E. S. Chang, M. Neuhof, N. D. Rubinstein, A. Diamant, H. Philippe, D. Huchon, P. Cartwright. Genomic insights into the evolutionary origin of Myxozoa within Cnidaria. Proceedings of the National Academy of Sciences, 2015; DOI: 10.1073/pnas.1511468112

Cite This Page:

American Friends of Tel Aviv University. "New discovery may redefine classifications in the animal kingdom: Close cousin of jellyfish evolved into a microscopic parasite that lives in fish, study shows." ScienceDaily. ScienceDaily, 18 November 2015. <www.sciencedaily.com/releases/2015/11/151118131730.htm>.
American Friends of Tel Aviv University. (2015, November 18). New discovery may redefine classifications in the animal kingdom: Close cousin of jellyfish evolved into a microscopic parasite that lives in fish, study shows. ScienceDaily. Retrieved May 23, 2017 from www.sciencedaily.com/releases/2015/11/151118131730.htm
American Friends of Tel Aviv University. "New discovery may redefine classifications in the animal kingdom: Close cousin of jellyfish evolved into a microscopic parasite that lives in fish, study shows." ScienceDaily. www.sciencedaily.com/releases/2015/11/151118131730.htm (accessed May 23, 2017).

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