Population genetics of the invasive snail Myosotella

Résumé

An invasive species can have a negative impact on the biodiversity, the ecosystem and the economy. Snails in the genus Myosotellaare native to coastal Europe, but they are also invasive. That means that we find Myosotellaall over the world. One theory is that they were spread by the help of human activities in different countries. We know well that local adaptations, gene flow and selection play an important role in the colonization of invasive species. Study the biogeography and the populations genetic is therefore necessary to better understand this invasive genus. The objective of this master thesis is to study the population genetics of Myosotella all over the world. We focus on the invasive aspect of the snails Myosotella and try to better understand their origin. We studied individuals coming from 16 different location by extracting DNA, Sanger sequencing and analyzing sequence variation. Visualization with a haplotype network and a phylogenetic tree have helped determine if there is a particular genotype which is worldwide spread or not. The results show threedifferent groups which are divided into threeputative species. Other groups of Azorean samples are also present in the middle of the haplotype network which could correspond to a fourth species. We compared our results with the distribution of species, and we suggest that one of the species is M. myosotis. These snails can have been transferred from one place to another by human activity which can explain why the sequences are similar. Further analyses should be done concerning the morphology as it is different within and between species, but also concerning the local adaptations of those snails.

la date de réponse	2024
langue originale	Anglais
L'institution diplômante	Universite de Namur Université Catholique de Louvain
Superviseur	Alice Dennis (Promoteur)