Publications by authors named "Jelmer Poelstra"
Natural host-plant resistance provides a sustainable solution to control insect outbreaks but can be limited due to insect counter-adaptation. The exact mechanisms of insect adaptation to host-plant resistance remain unclear in most systems. Some insect adaptations are controlled by epigenetic mechanisms, such as through noncoding RNA.
View Article and Find Full Text PDFRas signaling regulates many cellular processes in cancer development. While well-known Ras-related oncogenes, such as KRAS, have been extensively explored, the role of other Ras-related genes in cancer remains poorly studied. Dexamethasone-induced Ras-related protein 1 (RASD1), a member of the Ras superfamily, is widely expressed across various tissues and is involved in inhibiting cell growth and inducing apoptosis, suggesting a potential role as a tumor suppressor.
View Article and Find Full Text PDFBackground: Turkey arthritis reovirus (TARV) causes arthritic lameness in market-age turkeys. Since 2011, highly pathogenic TARV strains have caused significant economic losses in the turkey industry due to increased culling, reduced market weights, and decreased carcass quality, necessitating more effective control measures. Autogenous vaccine prevention strategies have been inefficacious partly due to a limited understanding of age-related susceptibility of turkeys to TARV.
View Article and Find Full Text PDFInsect herbivore evolution is tightly linked to changes in their host plants. Many plants have defensive traits that enable them to naturally tolerate and/or deter insect herbivory (host plant resistance; HPR). Some insects have adapted to overcome or resist these defenses (virulence).
View Article and Find Full Text PDFGene regulation by mating depends on time, diet, and body region in female Aedes aegypti.
J Insect Physiol
December 2024
Aedes aegypti is a major vector of several arboviruses that cause human mortality and morbidity. One method for controlling the spread of these viruses is to control mosquito reproduction. During mating, seminal fluid molecules and sperm are transferred and these stimuli influence female post-mating physiology and behavior.
View Article and Find Full Text PDFArticle Synopsis
- * The article proposes a comprehensive approach to accurately define species boundaries, using integrated evidence and focusing on geographic isolation, specifically applied to the mouse lemurs, a debated group of primates.
- * The study reveals that previous estimates of species diversity were inflated, mainly mistaking geographic variation for new species, and suggests that a clearer understanding of species limits can inform better conservation strategies.
Article Synopsis
- The study focuses on breeding disease-resistant soybean cultivars to combat Phytophthora root and stem rot by combining quantitative disease resistance (QDR) and gene-mediated resistance.
- Researchers conducted a time course analysis comparing gene expression in resistant soybean varieties (Conrad and M92-220) to susceptible ones (Sloan and mutants), revealing unique and shared defense pathways.
- The findings highlight 31 differentially expressed genes in resistant types that were not present in susceptible mutants, indicating potential novel QDR mechanisms and enhancing understanding of resistance networks in soybeans.
Article Synopsis
- The text discusses an emerging pathogen, identified as pv., which causes leaf spot disease in pepper plants, leading to significant economic losses in pepper production.
- A study involving strains from Ohio showed varying virulence levels on pepper seedlings, along with assessments of their growth, biofilm production, and motility, though these couldn't conclusively link to strains' virulence.
- Whole-genome sequencing revealed several virulence-related genes and antimicrobial resistance genes, but no strong correlations were established between genetic content and disease severity, suggesting the need for more research with larger sample sizes to understand the pathogen's effects on peppers.
High salt wastewater is produced in industries, including seafood and pickling processing. The salinity in such wastewaters has been shown to negatively impact biological treatment efficacy. Little is known about the changes in the microbial community structure in the mature biological 2 treatment systems, the impacts of salinity on community composition, and the shifts over time during operation.
View Article and Find Full Text PDFTransportation significantly affects the health and welfare of surplus dairy calves, largely due to the various stressors and pathogen exposures encountered during the process. Concurrently, an animal's microbiome is known to correlate with its health status, with stress-induced alterations in the microbiota potentially precipitating various diseases. This study aimed to compare the effects of transportation durations of 6, 12, or 16 h on the fecal microbiota in young surplus dairy calves.
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- Salmonellosis is a major foodborne illness in the USA, compounded by the rise of antimicrobial resistance, making treatment difficult.* -
- The study analyzed 80 Salmonella isolates from specialty crop farms in Northeast Ohio, identifying 15 serotypes and uncovering that 15% of samples contained antimicrobial resistance (AMR) genes, with 75% showing multidrug resistance.* -
- Plasmid analysis revealed diverse plasmids harboring 75% of AMR genes, highlighting specialty crop farms as a potential source for multidrug-resistant Salmonella, necessitating ongoing monitoring to safeguard human health.*
Article Synopsis
- The study highlights the growing importance of small specialty crop farms (SSCF) in the U.S. due to increased consumer interest in local produce.
- Researchers analyzed genomic diversity from bacteria isolated from dairy manure across 10 SSCFs in Northeast Ohio, identifying various sequence types and gene patterns indicating potential transmission between farms.
- Findings revealed that certain isolates carried genes that enhanced resistance to environmental stresses and antimicrobials, suggesting a complex interplay between bacteria and farm management practices over time.
Estimation of species divergence times in presence of cross-species gene flow.
Syst Biol
August 2023
Article Synopsis
- Cross-species introgression can skew estimates of when species diverged if not taken into account during phylogenomic analysis.
- Using simulations, the study demonstrated that incorporating introgression into the multispecies coalescent (MSC) framework leads to more accurate divergence time estimates.
- The results were further validated with real data from baobabs and Jaltomata species, showing that the new multispecies-coalescent-with-introgression (MSci) model can reliably handle cases of introgression while estimating divergence times.
Article Synopsis
- The study examines how the gut microbiome affects cancer treatment outcomes, with little prior research on its changes during cancer progression as influenced by diet and treatment methods like surgery and chemotherapy.
- Using a mouse model, researchers analyzed microbiome diversity and composition while categorizing mice based on their diet (sucrose and omega-3 fatty acids) and treatment (saline or chemotherapy), resulting in eight distinct groups.
- Findings indicated that cancer progression, diet, and treatment significantly impacted microbial diversity, with a notable decrease in diversity correlating with overall health, suggesting that these factors collectively influence the microbiome and potentially cancer treatment outcomes.
Article Synopsis
- The Asian rock pool mosquito, an invasive species first detected outside Asia in the early 1990s, has spread to North America and Europe and poses a risk due to its role in transmitting viruses like La Crosse and West Nile.
- A study conducted in Wooster, Ohio in 2021 utilized various traps to collect adult mosquitoes, confirming the species' establishment in the region.
- Molecular analysis showed this mosquito population has genetic similarities with those from Iowa and Canada, indicating multiple introductions and raising concerns about future arbovirus outbreaks in the area.
Article Synopsis
- Microsatellites have been widely used to study genetic diversity but their high mutation rates can create uncertainty in deeper evolutionary analyses, particularly in hybridization studies.
- This study employed RADseq data to investigate interspecific hybridization in a contact zone between two mouse lemur species in Madagascar, re-evaluating earlier findings suggesting hybridization based on microsatellite data.
- Findings showed no evidence of hybrid ancestry, indicating that previous claims of hybrid individuals were likely false positives, leading to the conclusion that the two species are fully reproductively isolated and changing our understanding of how reproducible isolation occurs in primates.
Article Synopsis
- Mutations are essential for evolution, and understanding their frequency and distribution helps us learn about evolutionary processes over time.
- This study estimates the mutation rate for gray mouse lemurs and finds it to be one of the highest among mammals at 1.52 mutations per site per generation, with an unexpected low number of paternal mutations.
- The research also confirms that reported mutation rates come with uncertainty and shows consistency in mutation patterns across different primate species when comparing various analysis methods.
A vertebrate adaptive radiation is assembled from an ancient and disjunct spatiotemporal landscape.
Proc Natl Acad Sci U S A
May 2021
Article Synopsis
- The study analyzes the adaptive radiation of Caribbean pupfishes by examining genomes to understand how adaptive alleles influenced their diversification in different environments.
- It highlights the role of ancient genetic variation from various regions, which led to new combinations through strong selection for specialized feeding strategies like scale-eating and molluscivory.
- The findings support theories of adaptive radiation, showing that adaptation occurred in stages, involving both existing gene variations and a key new mutation, emphasizing how ancient alleles can create new adaptations in changing environments.
Delimitation of cryptic species is increasingly based on genetic analyses but the integration of distributional, morphological, behavioral, and ecological data offers unique complementary insights into species diversification. We surveyed communities of nocturnal mouse lemurs (Microcebus spp.) in five different sites of northeastern Madagascar, measuring a variety of morphological parameters and assessing reproductive states for 123 individuals belonging to five different lineages.
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- * Multispecies coalescent (MSC) methods can help address these problems by accounting for gene tree discordance and using mutation rates to time branch lengths accurately.
- * The choice of analysis method (MSC vs. traditional phylogenetic methods) can significantly affect time estimates, and the paper outlines the pros and cons of each approach while offering practical tips for data analysis.
Article Synopsis
- Mouse lemurs, a diverse group of tiny primates in Madagascar, have seen a rapid increase in recognized species over the last 20 years, raising concerns about the oversplitting of this group.
- In a study focusing on an area in northeastern Madagascar, researchers used genetic data to examine two pairs of mouse lemur lineages, discovering significant differences in their populations and genetic structures.
- The findings support classifying one previously undescribed lineage as a separate species, while questioning the distinction of two other recognized species, indicating rapid evolution and reproductive isolation within these primates.
Article Synopsis
- Theory suggests that small populations accumulate harmful mutations more easily, leading to higher mutation loads.
- A study involving whole-genome sequencing of 147 crows from seven species found that island species with smaller geographic ranges had significantly higher mutation loads.
- These findings support the idea that small population sizes can lead to a greater risk of extinction, particularly for island species.
Article Synopsis
- - Madagascar's biodiversity, particularly its unique dwarf lemurs, faces severe threats from deforestation and climate change, leading to the need for genetic research due to their rarity.
- - Researchers conducted a comparative genomic study, producing the first comprehensive genome-wide genetic diversity estimates for various dwarf lemur species, including generating a reference genome for the fat-tailed dwarf lemur (Cheirogaleus medius).
- - The analysis revealed strong evolutionary relationships among species, identified areas of ancient genetic mixing possibly related to hibernation, and found low genetic diversity in isolated populations, emphasizing the importance of genomic studies for conservation efforts.
Article Synopsis
- The study focuses on how genetic barriers contribute to the creation of new species, using data from over 400 genomes of hybrid carrion and hooded crows in Europe.
- Researchers found that the majority of plumage color differences were influenced by interactions between a specific gene (NDP) and a large chromosomal region with limited recombination.
- The findings suggest that a small number of powerful genetic loci can play a significant role in preventing gene flow and maintaining distinct physical characteristics in these bird species.
Genomic data has revealed complex histories of colonization and repeated gene flow previously unrecognized in some of the most celebrated examples of sympatric speciation and radiation. However, much of the evidence for secondary gene flow into these radiations comes from summary statistics calculated from sparse genomic sampling without knowledge of which specific genomic regions introgressed. This tells us little about how gene flow potentially influenced sympatric diversification.
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