A tale of an invader: Reconstructing the genomic history of invasive
topmouth gudgeon (Pseudorasbora parva) populations.
Invasive species are significant contributors to global changes and
constitute a severe threat to biodiversity. Yet invasions offer an
incredible framework to understand how small and low-diverse introduced
populations adapt to novel environmental conditions and succeed in
colonizing large areas. However, due to the insufficient data on the
origin of the first introduced propagule and the first stage of
invasion, reconstructing a species’ invasion history is challenging.
Here, we applied genetic clustering methods and explicit admixture tests
combined with ABC models and Machine Learning algorithms to describe the
phylogeography of native and invasive populations and infer the most
probable demographic invasion scenarios of Pseudorasbora parva, a highly
invasive freshwater fish and the healthy carrier of a novel lethal
fungi-like pathogen (Sphaerothecum destruens), which is responsible for
the decline of several fish species in Europe. We found that the current
genetic structuring of the native P. parva range has been shaped by
waves of gene flow originating from southern and northern Chinese
populations. Furthermore, our results strongly suggest that the invasive
genetic diversity is the outcome of past recurrent global invasion
pathways of admixed native populations. Our study also illustrates how
the combination of admixture tests, ABC, Machine Learning can be used to
detect high-resolution demographic signatures and reconstruct an
integrative biological invasion history.