Biology subjects

Sherwin, W. B.

Publications and source records attributed to Sherwin, W. B..

4 recordsLinked to original sources

bioRxiv2022

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

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.

evolutionary biology↗

bioRxiv2021

Using historical museum samples to examine divergent and parallel evolution in the invasive starling

1.During the Anthropocene, Earth has experienced unprecedented habitat loss, native species decline, and global climate change. Concurrently, greater globalisation is facilitating species movement, increasing the likelihood of alien species establishment and propagation. There is a great need to understand what influences a species ability to persist or perish within a new or changing environment. Examining genes that may be associated with a species invasion success or persistence informs invasive species management, assists with native species preservation, and sheds light on important evolutionary mechanisms that occur in novel environments. This approach can be aided by coupling spatial and temporal investigations of evolutionary processes. Here we use the common starling, Sturnus vulgaris, to identify parallel and divergent evolutionary change between contemporary native and invasive range samples and their common ancestral population. To do this, we use reduced-representation sequencing of native samples collected recently in north-western Europe and invasive samples from Australia, together with museum specimens sampled in the UK during the mid-19th Century. We found evidence of parallel selection on both continents, possibly resulting from common global selective forces such as exposure to pollutants (e.g. TCDD) and food carbohydrate content. We also identified divergent selection in these populations, which might be related to adaptive changes in response to the novel environment encountered in the introduced Australian range. Interestingly, signatures of selection are equally as common within both invasive and native range contemporary samples. Our results demonstrate the value of including historical samples in genetic studies of invasion and highlight the ongoing and occasionally parallel role of adaptation in both native and invasive ranges.

evolutionary biology↗

bioRxiv2021

Concurrent invasions by European starlings (Sturnus vulgaris) suggest selection on shared genomic regions even after genetic bottlenecks

A species success during the invasion of new areas hinges on an interplay between demographic processes and the outcome of localized selection. Invasive European Starlings (Sturnus vulgaris) established populations in Australia and North America in the 19th century. Here, we compare whole-genome sequences among native and independently introduced European Starling populations from three continents to determine how demographic processes interact with rapid adaptive evolution to generate similar genetic patterns in these recent and replicated invasions. Our results confirm that a post-bottleneck expansion may in fact support local adaptation. We find that specific genomic regions have differentiated even on this short evolutionary timescale, and suggest that selection best explains differentiation in at least two of these regions. This infamous and highly mobile invader adapted to novel selection (e.g., extrinsic factors), perhaps in part due to the demographic boom intrinsic to many invasions.

evolutionary biology↗

bioRxiv2021

Transcript- and annotation-guided genome assembly of the European starling

The European starling, Sturnus vulgaris, is an ecologically significant, globally invasive avian species that is also suffering from a major decline in its native range. Here, we present the genome assembly and long-read transcriptome of an Australian-sourced European starling (S. vulgaris vAU), and a second North American genome (S. vulgaris vNA), as complementary reference genomes for population genetic and evolutionary characterisation. S. vulgaris vAU combined 10x Genomics linked-reads, low-coverage Nanopore sequencing, and PacBio Iso-Seq full-length transcript scaffolding to generate a 1050 Mb assembly on 1,628 scaffolds (72.5 Mb scaffold N50). Species-specific transcript mapping and gene annotation revealed high structural and functional completeness (94.6% BUSCO completeness). Further scaffolding against the high-quality zebra finch (Taeniopygia guttata) genome assigned 98.6% of the assembly to 32 putative nuclear chromosome scaffolds. Rapid, recent advances in sequencing technologies and bioinformatics software have highlighted the need for evidence-based assessment of assembly decisions on a case-by-case basis. Using S. vulgaris vAU, we demonstrate how the multifunctional use of PacBio Iso-Seq transcript data and complementary homology-based annotation of sequential assembly steps (assessed using a new tool, SAAGA) can be used to assess, inform, and validate assembly workflow decisions. We also highlight some counter-intuitive behaviour in traditional BUSCO metrics, and present BO_SCPLOWUSCOMPC_SCPLOW, a complementary tool for assembly comparison designed to be robust to differences in assembly size and base-calling quality. Finally, we present a second starling assembly, S. vulgaris vNA, to facilitate comparative analysis and global genomic research on this ecologically important species.

genomics↗