Genetic Population Structure and Allele Surfing During Range Expansion in Dynamic Habitats

Abstract

Expanding populations may loss genetic diversity because sequential founder events throughout a wave of demographic expansion may cause "allele surfing", as the alleles of founder individuals may propagate rapidly through space. The spatial components of allele surfing have been studied by geneticists, but have never been investigate on dynamic and shifting habitats. Here we used an individual-basedmodel (IBM) to study how interactions between different habitat restoration scenarios and biological characteristics (dispersal capacity) affect the spatial patterns of the genetic structure of a population during demographic expansion. We found that both habitat dynamics and dispersal capacity, as well as their interaction, were the drivers of emergent pattern of genetic diversity and allele surfing. Specifically, allele surfing is more common when a species with low dispersal capacity colonizes a large geographic area with slow restoration (low carrying capacity). Despite this, we showed that allele surfing can be reduced, or even avoided, by dispersal management through suitable habitat restoration. Thus, investigating how colonization generates a spatial variation in genetic diversity, and which parameters control the emergent genetic pattern, are essential steps to planning assisted gene flow, which is fundamental for an effective planning of habitat restoration.

Genetic and endosymbiotic diversity of Greek populations of Philaenus spumarius, Philaenus signatus and Neophilaenus campestris, vectors of Xylella fastidiosa

“…In a rapidly growing population, the genetic variation will generally be accumulated and maintained and eventually will be beneficial for species' success 43 . Due to the increased efficacy of selection in cleansing deleterious mutations and fixing advantageous ones, expanding populations often present faster evolution and increased population size 44,45 . When P. spumarius populations were grouped according to their geographical origin into North, Central and South Greece, the indices slightly changed since the groups of South and North Greece were less and more variable, respectively, than that of Central Greece.…”

Spatial genetic structure of European wild boar, with inferences on late-Pleistocene and Holocene demographic history

“…3) showed an ordination that is atypical for a postglacial expansion. Due to allele surfing (Braga et al 2019) and the consequential genetic drift, a PCoA on expanding populations typically opposes individuals of recolonized areas, not refugial areas (Franois et al 2010). The fact that our PCoA found the largest genetic differences among southern populations, rather than northern ones, shows that the signature of the LGM has become relatively weak in the autosomal genome.…”

Wolbachia-driven selective sweep in a range expanding insect species

“…These patterns are often due to the action of drift during rapid demographic spatial expansion and colonization [ 2 , 3 ]. Under these conditions, certain alleles and genotypes have been shown to spread in the newly colonized regions due to allele surfing [ 4 ], or due to selection for local adaptation in novel environments at the range limits [ 1 , 5 – 8 ]. Hidden processes and players may however confound these patterns, and challenge our full understanding of the evolutionary histories and genetic diversity of source and edge populations.…”