Russian biologists as part of an international team have discovered a single-celled predator, which may be one of the ancestors of all animals.
This is reported in the journal Current Biology.
The work of scientists was supported by the Russian Science Foundation.
The microscopic predator has been found in the coastal waters of Chile and is named Tunicaraptor.
Unlike most other flagellates, this microorganism is posterior flagellate, since the flagellum moves not forward, but backward (which makes it look like a sperm).
It also turned out that groups of such organisms are able to unite in colonies in order to absorb large prey.
“The tiny predator we discovered, Tunicaraptor, stands out from other unicellular animals.
When fed, it does not act alone, but as a multicellular aggregate.
Several predators unite on the surface of the prey, ”notes the head of the research project, chief researcher at the Institute for Biology of Inland Waters named after
Papanin Institute of RAS Denis Tikhonenkov.
The structure of the predatory flagellate Tunicaraptor
© Denis V. Tikhonenkov et al.
/ Current Biology, 2020
While studying the genetic code of the tiny predator, Denis Tikhonenkov and his colleagues found sequences typical of multicellular animals.
In particular, genes were found that are similar to human genes responsible for the development of the nervous system.
Tunicaraptor also showed genes responsible for adhesion, that is, cell adhesion.
“This process (adhesion -
) is one of the most important in the development of all multicellular organisms, it underlies the correct formation of tissues and organs.
It seems that these sequences have a common origin, and therefore the Tunicaraptor may be one of the earliest ancestors of all animals, ”suggests Denis Tikhonenkov.
According to scientists, the unusual structure of Tunicaraptor, its way of nutrition and genetic relationship with multicellular animals casts doubt on Haeckel's dominant hypothesis today, according to which multicellular evolved from one cell, whose daughter individuals did not disperse, but began to be responsible for certain functions within a single organism. ...
As noted by biologists, the discovery of zadnezhgutikovykh revives the interest of scientists in the hypothesis of "synzoospores" by A.A.
According to Zachvatkin, multicellular organisms evolved from protozoa, which, like Tunicaraptor, formed colonies during a complex life cycle.