Biologists seeking to determine why body gets rid of DNA

Identifying the molecular genetic mechanisms of hybridogenesis will help understand the logic behind evolution

Russian biologists, together with their colleagues from Japan, seek to determine which mechanisms trigger the elimination of the genome during the hybridization of closely related species. In other words, they are trying to understand why at some point a body recognizes the DNA of one of the parents as foreign and gets rid of it. The scientists have received a grant by the Russian Foundation for Basic Research to conduct the study.

‘Foreign genes can enter the body in different ways. For example, they can be brought in by viruses. There is nothing dangerous in this, because in the course of evolution a system has been developed, that recognizes these fragments and either marks them as “unreadable” or deletes them. This process of selective destruction is what we call the elimination of the genome — a mechanism common to all organisms,’ the project supervisor Vladimir Vershinin, Professor of the Department of Biodiversity and Bioecology of the UrFU Institute of Natural Sciences and Mathematics, explains. ‘Sometimes foreign fragments bring new biochemical capabilities that the body lacked. If the gene that was brought in works better, it can replace the native one. This is a natural process, which is then checked by selection through many years and generations.’

The scientists try to determine the trigger mechanism of genome elimination in frogs. The pool frogs of the Nizhny Novgorod region became subject to the experiments. Their genome is often eliminated during gametogenesis of hybrids.

Hybridogenesis in frogs was discovered in 1968, but the mechanism and cause of elimination has not yet been established.

‘All data in domestic publications on this issue were obtained in the course of the research of green frogs from the Kharkiv region. However, in the populations of this region polyploid forms are found among hybrids, which makes the task more interesting, but also complicates it,’ the biologist says. ‘Our population system is more convenient as a model, because it is simpler. There are no polyploid forms – triploids and tetraploids. However, despite the simplicity, the mechanism of genome elimination is universal, since it is crucial for the survival and reproduction of all species.’

The plans of the researchers also included the study of Japanese brown frogs, but eventually this idea was dropped.


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