| 1. |
|
|
| 2. |
- Dort, Hanna, 1995-, et al.
(author)
-
Removing specialized detoxification mechanisms reveals generalized responses in a host plant feeding specialist
-
Other publication (other academic/artistic)abstract
- Coevolutionary innovations are thought to be a large driver of insect and plant biodiversity. Several such innovations have arisen from gene duplication events and subsequent divergence between gene copies, including many adaptations that allow insects to overcome defensive host plant chemistry. However, the role adaptive gene duplicates play in a wider transcriptional framework is still poorly understood. Here, we use short-term feeding assays and CRISPR-Cas9 modified lines of cabbage white (Pieris brassicae) caterpillars to explore how non-functionalization of different members of a family of specialized detoxification genes affects the larval transcriptome at large. We find that the transcriptional response to host plant changes is strongest when all genes in the detoxification family are functional, suggesting that the gene family is part of a larger regulatory response to host plant defences. Further, among individuals lacking specialized detoxification genes, we find that certain general detoxification genes are uniquely upregulated in response to stressful host plant switches. Our results shed light on the importance of transcriptional plasticity in plant-insect interactions and lead to new hypotheses about the initial colonization of mustards by early pierid butterflies.
|
|
| 3. |
|
|
| 4. |
- Fuchs, Laura Iris Regina, et al.
(author)
-
A draft genome of the neritid snail Theodoxus fluviatilis
- 2023
-
In: G3. - 2160-1836.
-
Journal article (peer-reviewed)abstract
- The neritid snail Theodoxus fluviatilis is found across habitats differing in salinity, from shallow waters along the coast of the Baltic Sea to lakes throughout Europe. Living close to the water surface makes this species vulnerable to changes in salinity in their natural habitat, and the lack of a free-swimming larval stage limits this species’ dispersal. Together, these factors have resulted in a patchy distribution of quite isolated populations differing in their salinity tolerances. In preparation for investigating the mechanisms underlying the physiological differences in osmoregulation between populations that cannot be explained solely by phenotypic plasticity, we present here an annotated draft genome assembly for T. fluviatilis, generated using PacBio long reads, Illumina short reads, and transcriptomic data. While the total assembly size (1045 kb) is similar to those of related species, it remains highly fragmented (N scaffolds = 35,695; N50 = 74 kb) though moderately high in complete gene content (BUSCO single copy complete: 74.3%, duplicate: 2.6%, fragmented: 10.6%, missing: 12.5% using metazoa n = 954). Nevertheless, we were able to generate gene annotations of 21,220 protein-coding genes (BUSCO single copy complete: 65.1%, duplicate: 16.7%, fragmented: 9.1%, missing: 9.1% using metazoa n = 954). Not only will this genome facilitate comparative evolutionary studies across Gastropoda, as this is the first genome assembly for the basal snail family Neritidae, it will also greatly facilitate the study of salinity tolerance in this species. Additionally, we discuss the challenges of working with a species where high molecular weight DNA isolation is very difficult.
|
|
| 5. |
|
|
| 6. |
- Roberts, Kevin, 1989-, et al.
(author)
-
A time course analysis through diapause reveals dynamic temporal patterns of microRNAs associated with endocrine regulation in the butterfly Pieris napi
- 2024
-
In: Molecular Ecology. - 0962-1083 .- 1365-294X.
-
Journal article (peer-reviewed)abstract
- Organisms inhabiting highly seasonal environments must cope with a wide range of environmentally induced challenges. Many seasonal challenges require extensive physiological modification to survive. In winter, to survive extreme cold and limited resources, insects commonly enter diapause, which is an endogenously derived dormant state associated with minimized cellular processes and low energetic expenditure. Due to the high degree of complexity involved in diapause, substantial cellular regulation is required, of which our understanding primarily derives from the transcriptome via messenger RNA expression dynamics. Here we aim to advance our understanding of diapause by investigating microRNA (miRNA) expression in diapausing and direct developing pupae of the butterfly Pieris napi. We identified coordinated patterns of miRNA expression throughout diapause in both head and abdomen tissues of pupae, and via miRNA target identification, found several expression patterns to be enriched for relevant diapause-related physiological processes. We also identified two candidate miRNAs, miR-14-5p and miR-2a-3p, that are likely involved in diapause progression through their activity in the ecdysone pathway, a critical regulator of diapause termination. miR-14-5p targets phantom, a gene in the ecdysone synthesis pathway, and is upregulated early in diapause. miR-2a-3p has been found to be expressed in response to ecdysone, and is upregulated during diapause termination. Together, the expression patterns of these two miRNAs match our current understanding of the timing of hormonal regulation of diapause in P. napi and provide interesting candidates to further explore the mechanistic role of microRNAs in diapause regulation.
|
|
| 7. |
- Steward, Rachel A., et al.
(author)
-
Genetic constraints in genes exhibiting splicing plasticity in facultative diapause
- 2024
-
In: Heredity. - 0018-067X .- 1365-2540. ; 132, s. 142-155
-
Journal article (peer-reviewed)abstract
- Phenotypic plasticity is produced and maintained by processes regulating the transcriptome. While differential gene expression is among the most important of these processes, relatively little is known about other sources of transcriptional variation. Previous work suggests that alternative splicing plays an extensive and functionally unique role in transcriptional plasticity, though plastically spliced genes may be more constrained than the remainder of expressed genes. In this study, we explore the relationship between expression and splicing plasticity, along with the genetic diversity in those genes, in an ecologically consequential polyphenism: facultative diapause. Using 96 samples spread over two tissues and 10 timepoints, we compare the extent of differential splicing and expression between diapausing and direct developing pupae of the butterfly Pieris napi. Splicing differs strongly between diapausing and direct developing trajectories but alters a smaller and functionally unique set of genes compared to differential expression. We further test the hypothesis that among these expressed loci, plastically spliced genes are likely to experience the strongest purifying selection to maintain seasonally plastic phenotypes. Genes with unique transcriptional changes through diapause consistently had the lowest nucleotide diversity, and this effect was consistently stronger among genes that were differentially spliced compared to those with just differential expression through diapause. Further, the strength of negative selection was higher in the population expressing diapause every generation. Our results suggest that maintenance of the molecular mechanisms involved in diapause progression, including post-transcriptional modifications, are highly conserved and likely to experience genetic constraints, especially in northern populations of P. napi.
|
|
| 8. |
- Tunström, Kalle, 1991-, et al.
(author)
-
Evidence for a single, ancient origin of a genus-wide alternative life history strategy
- 2023
-
In: Science Advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 9:12
-
Journal article (peer-reviewed)abstract
- Understanding the evolutionary origins and factors maintaining alternative life history strategies (ALHS) within species is a major goal of evolutionary research. While alternative alleles causing discrete ALHS are expected to purge or fix over time, one-third of the ~90 species of Colias butterflies are polymorphic for a female-limited ALHS called Alba. Whether Alba arose once, evolved in parallel, or has been exchanged among taxa is currently unknown. Using comparative genome-wide association study (GWAS) and population genomic analyses, we placed the genetic basis of Alba in time-calibrated phylogenomic framework, revealing that Alba evolved once near the base of the genus and has been subsequently maintained via introgression and balancing selection. CRISPR-Cas9 mutagenesis was then used to verify a putative cis-regulatory region of Alba, which we identified using phylogenetic foot printing. We hypothesize that this cis-regulatory region acts as a modular enhancer for the induction of the Alba ALHS, which has likely facilitated its long evolutionary persistence.
|
|
