Mus domesticus

Aeolian house mouse: an extraordinary evolutionary model, the result of a thousand-year-old friendship with humans

The study of Sapienza University identifies in the small animal's genetic inheritance the key to understand the complex mechanisms linked to the appearance of new species. The results, published on Molecular Biology and Evolution, represent a powerful instrument to comprehend the intricate mechanisms that lead to the formation of new species

According to the Chinese calendar, 2020 is the year of the rat, and Molecular Biology and Evolution journal wanted to celebrate this event by giving particular scientific attention to the studies about the evolutionary genetics of mice and rats.
Among these studies, the journal selected and published the work of the research group coordinated by Riccardo Castiglia of the Department of Biology and Biotechnologies "Charles Darwin" of Sapienza University about the evolution of Mus domesticus, the house mouse, in the Aeolian archipelago in Southern Italy (Sicily).

The research, through "Next Generation Sequencing", NGS, analysed the extraordinary chromosome diversity of the house mouse population inhabiting the archipelago, from a new point of view. The genetic peculiarity of this animal is the result of a thousand-year-old cohabitation with human populations, which has had a crucial role in its evolutionary process

The origin of the house mouse dates back to the Neolithic Age, in the Middle East, where it was a commensal of man who, at that time, was starting to live in permanent settlements. From the Middle East, together with its travelling companion, it moved and reached the central Mediterranean area around 3000 years ago, during the Iron Age. At the time, the Aeolian Islands represented a crossroads for merchant ships, one of the primary trade routes for obsidian, the precious volcanic black glass.

"These islands – says Emanuela Solano, author of the study – are an incredible source of genetic variability and represent a real paradise for evolutionary biologists. Thanks to our collaboration with the University of Konstanz, for the first time, we could combine the analysis of chromosomal evolution in the Mus domesticus, which has been our area of expertise for many years, with a genome-wide approach, based on the investigation of the whole genome."

The researchers observed how Mus domesticus undergone, over time and in many of the areas it has "colonised" several chromosomal mutations (called Robertsonian translocation), from which originated the so-called chromosomal races, that is numerous populations with a variable number of chromosomes. In this particular case, the researchers highlighted how such chromosomal diversity emerged within the archipelago, and it is not the result of multiple colonisations from the surrounding areas, as the scientific community used to believe in the past.

Moreover, it has been proved how complex hybridization mechanisms had, in fact, "reshuffled" the chromosomal races present on the islands to reach new chromosome combinations.


"The mouse – says Solano – thanks to the presence of chromosomal races, becomes a model for all those studies aimed at understanding the mechanisms linked to the origin of a new species (speciation) and the role of chromosomal mutations in a hybrid's fertility."

"The resolution of this complex chromosomal evolutionary model – concludes Riccardo Castiglia – proved that the house mouse has great "evolutionary capabilities" and the wild populations may be the source of surprising discoveries on evolution. It represents a powerful instrument to comprehend the intricate mechanisms that lead to the formation of new species and a proxy for studying our planet's biodiversity."

 

References:

Reconstructing the evolutionary history of chromosomal races on islands: a genome-wide analysis of natural house mouse populations - Paolo Franchini, Andreas F Kautt, Alexander Nater, Gloria Antonini, Riccardo Castiglia, Axel Meyer, Emanuela Solano - Molecular Biology and Evolution https://doi.org/10.1093/molbev/msaa118

 

Further Information

Riccardo Castiglia
Department of Biology and Biotechnologies "Charles Darwin"
riccardo.castiglia@uniroma1.it

Emanuela Solano
Department of Biology and Biotechnologies "Charles Darwin"
emanuela.solano@uniroma1.it

 

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Friday, 29 May 2020

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