Swiss Scientists Explain Evolution of Extreme Parasites

Related Articles

Extreme adaptations of species usually cause such considerable changes that their evolutionary history is difficult to recreate. Zoologists at the University of Basel in Switzerland have now uncovered a new parasite species that represents the missing link between fungi and an extreme group of parasites. Researchers now have the information to understand for the first time the evolution of these parasites, which cause disease in humans and animals. The study has been published in the latest issue of the scientific journal Proceedings of the National Academy of Sciences (PNAS). 

Parasites use their hosts to simplify their own lives. To do this, they evolved features that are so extreme that it is often impossible to compare them to other species. The evolution of these extreme adaptations is often too difficult to reconstruct. The research group lead by Prof. Dieter Ebert from the Department of Environmental Science at the University of Basel has now found the missing link that explains how this large group of extreme parasites, the microsporidia, has evolved. Scientists from Sweden and the U.S supported the team in their work.

Microsporidia are a large group of extreme parasites that occupy humans and animals and create substantial damage for health care systems and agriculture; there are over 1,200 known species. They live inside their host’s cells and have highly specialised features, including: They are only able to reproduce inside the host’s cells, they have the smallest known genome of all organisms containing a cell nucleus (eukaryotes) and they don’t posses any mitochondria of their own (the cell’s power plant). Along with all this, they developed a specialised infection apparatus, the polar tube, which they use to insert themselves into the cells of their host. As a result of their phenomenal high molecular evolution rate, genome analysis has thus far been rather unsuccessful: their great genomic divergence from all other known organisms further complicates the study of their evolutionary lineage.

Between fungi and parasite

 

The team of zoologists lead by Prof. Dieter Ebert has been studying the evolution of microsporidia for a number of years. When they discovered a new parasite in water fleas a couple of years ago, they classified this undescribed species as a microsporidium, as it possessed the unique harpoon-like infection apparatus (the polar-tube), one of the classifying features of microsporidia. The analysis of the entire genome contained several surprises: The genome resembles more that of a fungi than a microsporidium and, in addition, also contains a mitochondrial genome. The new species, now named Mitosporidium daphniae, therefore represents the missing link between fungi and microsporidia.

With the help of scientists in Sweden and the U.S., the Basel researchers rewrote the evolutionary history of microsporidia. Firstly, they demonstrated that the new species derives from the ancestors of all known microsporidians and further, that the microsporidians are derivative from the most ancient fungi; there its exact place in the tree of life has finally been discovered. Further research has confirmed that the species does in fact have a microsporidic, intracellular and parasitic lifestyle, but that its genome is rather atypical for a microsporidium. It resembles much more the genome of their fungal ancestors.

Electronmicroscopic picture of the spores of the newly discovered microsporidium M. daphniae: Ronny Larsson
Electronmicroscopic picture of the spores of the newly discovered microsporidium M. daphniae: Ronny Larsson

Genome modifications

The scientists came to the conclusion that the microsporidia adopted intracellular parasitism first and later altered their genome significantly. These genetic adaptations include the loss of mitochondria, as well as extreme metabolic and genomic simplification. “Our results are not only a milestone for the research on microsporidia, but they are also of great interest to the study of parasitic-specific adaptations in evolution in general”, explains Ebert.

 

 

 

Contributing Source: Universität Basel

Header Image Source: WikiPedia

Download the HeritageDaily mobile application on iOS and Android

More on this topic

LATEST NEWS

Roman Villa of Tiberius and the Cave of Imperial Pleasure

The Villa of Tiberius is a ruined Roman villa complex located in the present-day town of Sperlonga, in the province of Latina on the western coast of Italy.

Archaeologists Excavate 1,600-Year-Old Burial Containing Ornate Treasures

Archaeologists excavating a burial ground have discovered a grave containing ornate grave goods from the 5th century AD, a period of instability during the collapse of the Western Roman Empire.

Archaeologists Discover Ancient Settlements Associated With “Polish Pyramids”

Archaeologists conducting a detailed study of the area near the Kujawy megalithic tombs, dubbed the “Polish Pyramids”, have identified the associated settlements of the tomb builders.

Rocky Planet Discovered in Virgo Constellation Could Change Search For Life in Universe

A newly discovered planet could be our best chance yet of studying rocky planet atmospheres outside the solar system, a new international study involving UNSW Sydney shows.

Sungbo’s Eredo – The “Queen of Sheba’s Embankment”

Sungbo’s Eredo is one of the largest man-made monuments in Africa, consisting of a giant system of ditches and embankments that surrounds the entire ljebu Kingdom in the rain forests of south-western Nigeria.

Woolly Mammoths May Have Shared the Landscape With First Humans in New England

Woolly mammoths may have walked the landscape at the same time as the earliest humans in what is now New England, according to a Dartmouth study published in Boreas.

Prehistoric killing machine exposed

Judging by its massive, bone-crushing teeth, gigantic skull and powerful jaw, there is no doubt that the Anteosaurus, a premammalian reptile that roamed the African continent 265 to 260 million years ago - during a period known as the middle Permian - was a ferocious carnivore.

Noushabad – The Hidden Underground City

Noushabed, also called Oeei or Ouyim is an ancient subterranean city, built beneath the small town of Nushabad in present-day Iran.

Popular stories

Noushabad – The Hidden Underground City

Noushabed, also called Oeei or Ouyim is an ancient subterranean city, built beneath the small town of Nushabad in present-day Iran.

Ani – The Abandoned Medieval City

Ani is a ruined medieval city, and the former capital of the Bagratid Armenian kingdom, located in the Eastern Anatolia region of the Kars province in present-day Turkey.

Interactive Map of Earth’s Asteroid and Meteor Impact Craters

Across the history of our planet, around 190 terrestrial impact craters have been identified that still survive the Earth’s geological processes, with the most recent event occurring in 1947 at the Sikhote-Alin Mountains of south-eastern Russia.

The Sunken Town of Pavlopetri

Pavlopetri, also called Paulopetri, is a submerged ancient town, located between the islet of Pavlopetri and the Pounta coast of Laconia, on the Peloponnese peninsula in southern Greece.