Jumping genes to order marsupial evolutionary jumps

2010/11/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Eboluzioa
• Genetika
• Zoologia

The origin of the marsupials is in South America and migrated to Australia in a single migration

They use very special genes, known as portraits, to explain the evolution and distribution of marsupials at the Münster University in Germany. The group of marsupials consists of more than 300 species, including kangaroos, tsarigueas and the devil of Tasmania, which live mainly in America and Australia.

The genetic and fossil data collected so far do not yield converging results on the evolution of these animals. DNA suggests that a South American ancestor arrived in Australia when the continents were still united, and from there each group evolved separately. As for fossils, however, there seem to have been more setbacks.

To somehow clarify this confusion, the biologists of the University of Münster looked at some pieces of DNA that until then had not studied, that is, in the retoposons. They are small fragments of DNA that are released from DNA, copied and inserted into some other position of the genome. In addition, the usual thing is that when going from one to another there are stable sequences and there are no mutations.

Therefore, they are considered reliable sources of information to know the evolution of the species: if the two species have a retroposón in a certain place of the genome, they will probably have more kinship with each other than with one that does not have that retroposón. And if a certain species does not have a retroposon than the vast majority of others, it may be a pre-existing species or an ancient species.

The study found that all marsupial species share 10 portraits. Therefore, they have confirmed that all come from the same ancestor. In addition, they have come to the conclusion that those in South America are in the oldest branches of the phylogenetic tree, since they are the least retroposones have. Finally, retrotrophies have suggested that Australian and American Marsupials have progressed separately, meaning that as they evolve they have not had much contact with each other. Taking all the data together, the researchers point out that there was a single migration from America to Australia, from which all existing species emerged.