Biology subjects

Sperling, F. A. H.

Publications and source records attributed to Sperling, F. A. H..

4 recordsLinked to original sources

bioRxiv2024

Whole-genome evaluation of genetic rescue: the case of a curiously isolated and endangered butterfly

Genetic rescue, or the translocation of individuals among populations to augment gene flow, can help ameliorate inbreeding depression and loss of adaptive potential in small and isolated populations. Genetic rescue is currently under consideration for an endangered butterfly in Canada, the half-moon hairstreak (Satyrium semiluna). A small, unique population persists in Waterton Lakes National Park, Alberta, isolated from other populations by >350km. However, whether genetic rescue would actually be helpful has not been evaluated. Here, we generate the first chromosome-level genome assembly and whole-genome resequence data for the species. We find that the Alberta populations genetic diversity is extremely low and very divergent from the nearest populations in British Columbia and Montana. Runs of homozygosity suggest this is due to a long history of inbreeding, and coalescent analyses show that the population has been small and isolated, yet stable for up to 40k years. When a population maintains its viability despite inbreeding and low genetic diversity, it has likely undergone purging of deleterious recessive alleles and could be threatened by their reintroduction via genetic rescue. Ecological niche modelling indicates that the Alberta population also exhibits environmental associations that are atypical of the species. Together, these results suggest that population crosses are likely to result in outbreeding depression. We infer that, in this case, genetic rescue has a relatively unique potential to be harmful rather than helpful at present. However, due to reduced adaptive potential, the Alberta may still benefit from future genetic rescue as climate conditions change. Proactive experimental population crosses should be completed to assess reproductive compatibility and offspring fitness.

ecology↗

bioRxiv2024

In-Flights of Outbreak Populations of Mountain Pine Beetle Alter the Local Genetic Structure of Established Populations a Decade After Range Expansion

Mountain pine beetles began to appear at epidemic levels in Alberta, Canada, in 2006, following six years of extensive outbreaks in neighboring British Columbia. We assessed the effect of genetic MPB in-flights from the peak of the outbreak on the genetic structure of established populations of MPB and the change over time in novel regions colonized by these inflights. We used five locations sampled during the peak of the outbreak (2005/2007) and re-sampled in 2016. We performed a ddRADseq protocol to generate a SNP dataset via single-end Illumina sequencing. We detected a northern and southern genetic cluster in both sampling sets (2005/2007 and 2016) and a demographic shift in cluster assignment after [~]10 generations from south to north in two of the sites in the path of the northern outbreak. Fst values were significantly different between most sites in the same years and between the same sites at different years, with some exceptions for northern sites established by inflights. Overall, sites in the spreading path of the MPB outbreak have taken on the genetic structure of the contiguous northern outbreak except for an isolated site in Golden, BC, and in Mount Robson Provincial Park where populations are admixed between north and south. Our results suggest that range expansion during insect outbreaks can alter the genetic structure of established populations and lead to interbreeding between populations.

genomics↗

bioRxiv2023

Toward transparent taxonomy: an interactive web-tool for evaluating competing taxonomic arrangements

1. Informative and consistent taxonomy above the species level is essential to communication about evolution, biodiversity, and conservation, and yet the practice of taxonomy is considered opaque and subjective by non-taxonomist scientists and the public alike. While various proposals have tried to make the basis for ranking and inclusiveness of taxa more transparent and objective, widespread adoption of these ideas has lagged. 2. Here, we present TaxonomR, an interactive online decision-support tool to evaluate alternative taxonomic classifications. This tool implements an approach that quantifies the criteria commonly used in taxonomic treatments and allows the user to interactively manipulate weightings for different criteria to compare scores for taxonomic groupings under those weights. 3. We use the butterfly taxon Argynnis to demonstrate how different weightings applied to common taxonomic criteria result in fundamentally different genus-level classifications that are predominantly used in different continents and geographic regions. These differences are objectively compared and quantified using TaxonomR to evaluate the kinds of criteria that have been emphasized in earlier classifications, and the nature of the support for current alternative taxonomic arrangements. 4. The main role of TaxonomR is to make taxonomic decisions transparent via an explicit prioritization scheme. TaxonomR is not a prescriptive application. Rather, it aims to be a tool for facilitating our understanding of alternative taxonomic classifications that can, in turn, potentially support global harmony in biodiversity assessments through evidence-based discussion and community-wide resolution of historically entrenched taxonomic tensions.

evolutionary biology↗

bioRxiv2017

Testing the role of the Red Queen and Court Jester as drivers of the macroevolution of Apollo butterflies

In macroevolution, the Red Queen (RQ) model posits that biodiversity dynamics depend mainly on species-intrinsic biotic factors such as interactions among species or life-history traits, while the Court Jester (CJ) model states that extrinsic environmental abiotic factors have a stronger role. Until recently, a lack of relevant methodological approaches has prevented the unraveling of contributions from these two types of factors to the evolutionary history of a lineage. Here we take advantage of the rapid development of new macroevolution models that tie diversification rates to changes in paleoenvironmental (extrinsic) and/or biotic (intrinsic) factors. We inferred a robust and fully-sampled species-level phylogeny, as well as divergence times and ancestral geographic ranges, and related these to the radiation of Apollo butterflies (Parnassiinae) using both extant (molecular) and extinct (fossil/morphological) evidence. We tested whether their diversification dynamics are better explained by a RQ or CJ hypothesis, by assessing whether speciation and extinction were mediated by diversity-dependence (niche filling) and clade-dependent host-plant association (RQ) or by large-scale continuous changes in extrinsic factors such as climate or geology (CJ). For the RQ hypothesis, we found significant differences in speciation rates associated with different host-plants but detected no sign of diversity-dependence. For CJ, the role of Himalayan-Tibetan building was substantial for biogeography but not a driver of high speciation, while positive dependence between warm climate and speciation/extinction was supported by continuously varying maximum-likelihood models. We find that rather than a single factor, the joint effect of multiple factors (biogeography, species traits, environmental drivers, and mass extinction) is responsible for current diversity patterns, and that the same factor might act differently across clades, emphasizing the notion of opportunity. This study confirms the importance of the confluence of several factors rather than single explanations in modeling diversification within lineages.

evolutionary biology↗