Contrasting patterns of single nucleotide polymorphisms and structural variations across multiple invasions

Abstract

Adaptive divergence is a fundamental process that shapes genetic diversity within and across species. Structural variants (SVs) are large-scale genetic differences (insertion, deletions, and rearrangements) within a species or population. SVs can cause important functional differences in the individuals phenotype. Characterising SVs across invasive species will help fill knowledge gaps regarding how patterns of genetic diversity and genetic architecture shape rapid adaptation in response to new selection regimes. In this project we seek to understand patterns in genetic diversity within the globally invasive European starling, Sturnus vulgaris. We use whole genome sequencing of eight native United Kingdom (UK), eight invasive North America (NA), and 33 invasive Australian (AU) starlings to examine patterns in genome-wide SNPs and SVs between populations and within Australia. The findings of our research demonstrate that even within recently diverged lineages or populations, there may be high amounts of structural variation. Further, patterns of genetic diversity estimated from SVs do not necessarily reflect relative patterns from SNP data, either when considering patterns of diversity along the length of the organisms chromosomes (owing to enrichment of SVs in sub telomeric repeat regions), or interpopulation diversity patterns (possibly a result of altered selection regimes or introduction history). Finally, we find that levels of balancing selection within the native range differ across SNP and SV of different classes and outlier classifications. Overall, our results demonstrate that the processes that shape allelic diversity within populations is complex and supports the need for further investigation of SVs across a range of taxa to better understand correlations between oft well studied SNP diversity and that of SVs.