Genetic and phenotypic diversification in a widespread fish, the Sailfin Molly (Poecilia latipinna).

Widespread species often experience significant environmental clines over the area they naturally occupy. We investigated a widespread livebearing fish, the Sailfin molly (Poecilia latipinna) combining genetic, life-history, and environmental data, asking how structured populations are. Sailfin mollies can be found in coastal freshwater and brackish habitats from roughly Tampico, Veracruz in Mexico to Wilmington, North Carolina, in the USA. In addition, they are found inland on the Florida peninsula. Using microsatellite DNA, we genotyped 168 individuals from 18 populations covering most of the natural range of the Sailfin molly. We further determined standard life-history parameters for both males and females for these populations. Finally, we measured biotic and abiotic parameters in the field. We found six distinct genetic clusters based on microsatellite data, with very strong indication of isolation by distance. However, we also found significant numbers of migrants between adjacent populations. Despite genetic structuring we did not find evidence of cryptic speciation. The genetic clusters and the migration patterns do not match paleodrainages. Life histories vary between populations but not in a way that is easy to interpret. We suggest a role of humans in migration in the sailfin molly, for example in the form of a ship channel that connects southern Texas with Louisiana which might be a conduit for fish migration.

Combined use of ecotoxicity tools and physicochemical analysis for evaluating potential toxicity of treated natural rubber processing effluents and receiving waters.

Potential toxicity of treated effluents of selected natural rubber processing industries was evaluated by integrating physicochemical analysis with Daphnia magna and Poecilia reticulata bioassays as ecotoxicity tools. Further, the efficacy of the constructed wetland treatments practiced by the industries for reducing the ecotoxicity of the final effluents reaching the receiving water course was assessed. Even after passing through the constructed wetlands, some of the measured physicochemical parameters of the final effluents did not comply with the stipulated rubber processing effluent regulatory limits. Acute toxicity data of treated effluents demonstrated greater susceptibility of D. magna compared to P. reticulata. Erythrocytic abnormality tests with P. reticulata revealed that rubber industry effluents contained cytogenotoxic contaminations which had not been completely eliminated by the treatment processes. Wetland treatment technique was not effective in reducing the cytogenotoxic effects of final effluents reaching the receiving water course. The use of ecotoxicity tools for optimization of rubber industry effluent treatment processes would help to reduce potential toxic/cytogenotoxic effects of effluent receiving waterbodies considering sustainable development goals focusing on ecosystem safety.

Behavioral responses of a clonal fish to perceived predation risk.

Predation threat is a major driver of behavior in many prey species. Animals can recognize their relative risk of predation based on cues in the environment, including visual and/or chemical cues released by a predator or from its prey. When threat of predation is high, prey often respond by altering their behavior to reduce their probability of detection and/or capture. Here, we test how a clonal fish, the Amazon molly (Poecilia formosa), behaviorally responds to predation cues. We measured aggressive and social behaviors both under 'risk', where chemical cues from predatory fish and injured conspecifics were present, and control contexts (no risk cues present). We predicted that mollies would exhibit reduced aggression towards a simulated intruder and increased sociability under risk contexts as aggression might increase their visibility to a predator and shoaling should decrease their chance of capture through the dilution effect. As predicted, we found that Amazon mollies spent more time with a conspecific when risk cues were present, however they did not reduce their aggression. This highlights the general result of the 'safety in numbers' behavioral response that many small shoaling species exhibit, including these clonal fish, which suggests that mollies may view this response as a more effective anti-predator response compared to limiting their detectability by reducing aggressive conspecific interactions.

Nascent transcription reveals regulatory changes in extremophile fishes inhabiting hydrogen sulfide-rich environments.

Regulating transcription allows organisms to respond to their environment, both within a single generation (plasticity) and across generations (adaptation). We examined transcriptional differences in gill tissues of fishes in the Poecilia mexicana species complex (family Poeciliidae), which have colonized toxic springs rich in hydrogen sulfide (H2S) in southern Mexico. There are gene expression differences between sulfidic and non-sulfidic populations, yet regulatory mechanisms mediating this gene expression variation remain poorly studied. We combined capped-small RNA sequencing (csRNA-seq), which captures actively transcribed (i.e. nascent) transcripts, and messenger RNA sequencing (mRNA-seq) to examine how variation in transcription, enhancer activity, and associated transcription factor binding sites may facilitate adaptation to extreme environments. csRNA-seq revealed thousands of differentially initiated transcripts between sulfidic and non-sulfidic populations, many of which are involved in H2S detoxification and response. Analyses of transcription factor binding sites in promoter and putative enhancer csRNA-seq peaks identified a suite of transcription factors likely involved in regulating H2S-specific shifts in gene expression, including several key transcription factors known to respond to hypoxia. Our findings uncover a complex interplay of regulatory processes that reflect the divergence of extremophile populations of P. mexicana from their non-sulfidic ancestors and suggest shared responses among evolutionarily independent lineages.

A novel neurotropic microsporidium from the swamp guppy Micropoecilia picta from Grenada, West Indies.

A novel microsporidium was observed in wild swamp guppies Micropoecilia picta from Levera Pond within Levera National Park Grenada, West Indies. Initial observations indicated similarity with Pseudoloma neurophilia, an important pathogen in zebrafish Danio rerio. P. neurophilia exhibit broad host specifity, including members of the family Poecillidae, and both parasites infect the central nervous system. However, spore morphology and molecular phylogeny based on rDNA showed that the swamp guppy microsporidium (SGM) is distinct from P. neurophilia and related microsporidia (Microsporidium cerebralis and M. luceopercae). Spores of the SGM were smaller than others in the clade (3.6 µm long). Differences were also noted in histology; the SGM formed large aggregates of spores within neural tissues along with a high incidence of numerous smaller aggregates and single spores within the surface tissue along the ventricular spaces that extended submeninx, whereas P. neurophilia and M. cerebralis infect deep into the neuropile and cause associated lesions. Analysis of small subunit ribosomal DNA sequences showed that the SGM was <93% similar to these related microsporidia. Nevertheless, one of 2 commonly used PCR tests for P. neurophilia cross reacted with tissues infected with SGM. These data suggest that there could be other related microsporidia capable of infecting zebrafish and other laboratory fishes that are not being detected by these highly specific assays. Consequently, exclusive use of these PCR tests may not accurately diagnose other related microsporidia infecting animals in laboratory and ornamental fish facilities.

Sub-acute exposure of male guppies (Poecilia reticulata) to environmentally relevant concentrations of PFOA and GenX induces significant changes in the testis transcriptome and reproductive traits.

Poly- and perfluoroalkyl substances (PFAS) are frequently detected in the environment and are linked to adverse reproductive health outcomes in humans. Although legacy PFAS have been phased out due to their toxicity, alternative PFAS are increasingly used despite the fact that information on their toxic effects on reproductive traits is particularly scarce. Here, we exposed male guppies (Poecilia reticulata) for a short period (21 days) to an environmentally realistic concentration (1 ppb) of PFOA, a legacy PFAS, and its replacement compound, GenX, to assess their impact on reproductive traits and gene expression. Exposure to PFAS did not impair survival but instead caused sublethal effects. Overall, PFAS exposure caused changes in male sexual behaviour and had detrimental effects on sperm motility. Sublethal variations were also seen at the transcriptional level, with the modulation of genes involved in immune regulation, spermatogenesis, and oxidative stress. We also observed bioaccumulation of PFAS, which was higher for PFOA than for GenX. Our results offer a comprehensive comparison of these two PFAS and shed light on the toxicity of a newly emerging alternative to legacy PFAS. It is therefore evident that even at low concentrations and with short exposure, PFAS can have subtle yet significant effects on behaviour, fertility, and immunity. These findings underscore the potential ramifications of pollution under natural conditions and their impact on fish populations.

Multiple environmental stressors affect predation pressure in a tropical freshwater system.

Environmental change can alter predator-prey dynamics. However, studying predators in the context of co-occurring environmental stressors remains rare, especially under field conditions. Using in situ filming, we examined how multiple stressors, including temperature and turbidity, impact the distribution and behaviour of wild fish predators of Trinidadian guppies (Poecilia reticulata). The measured environmental variables accounted for 17.6% of variance in predator species composition. While predator species differed in their associations with environmental variables, the overall prevalence of predators was greatest in slow flowing, deeper, warmer and less turbid habitats. Moreover, these warmer and less turbid habitats were associated with earlier visits to the prey stimulus by predators, and more frequent predator visits and attacks. Our findings highlight the need to consider ecological complexity, such as co-occurring stressors, to better understand how environmental change affects predator-prey interactions.

Hepatic transcriptome, transcriptional effects and antioxidant responses in Poecilia vivipara exposed to sanitary sewage.

Aquatic environments are subject to threats from multiple human activities, particularly through the release of untreated sanitary sewage into the coastal environments. These effluents contain a large group of natural or synthetic compounds referred to as emerging contaminants. Monitoring the types and quantities of toxic substances in the environment, especially complex mixtures, is an exhausting and challenging task. Integrative effect-based tools, such as biomarkers, are recommended for environmental quality monitoring programs. In this study, fish Poecilia vivipara were exposed for 24 and 96 h to raw untreated sewage diluted 33 % (v/v) in order to identify hepatic genes to be used as molecular biomarkers. Through a de novo hepatic transcriptome assembly, using Illumina MiSeq, 54,285 sequences were assembled creating a reference transcriptome for this guppy species. Transcripts involved in biotransformation systems, antioxidant defenses, ABC transporters, nuclear and xenobiotic receptors were identified and evaluated by qPCR. Sanitary sewage induced transcriptional changes in AhR, PXR, CYP2K1, CYP3A30, NQO1, UGT1A1, GSTa3, GSTmu, ST1C1, SOD, ABCC1 and SOX9 genes from liver of fish, particularly after 96 h of exposure. Changes in hepatic enzyme activities were also observed. The enzymes showed differences in fish exposed to both periods, while in the gills there was a prevalence of significant results after 96 h. The observed differences were associated to gender and/or to sewage exposure. The obtained results support the use of P. vivipara as sentinel and model organism for ecotoxicological studies and evidence the importance of understanding the differential responses associated to gender.

Associating with kin selects for disease resistance and against tolerance.

Behavioural and physiological resistance are key to slowing epidemic spread. We explore the evolutionary and epidemic consequences of their different costs for the evolution of tolerance that trades off with resistance. Behavioural resistance affects social cohesion, with associated group-level costs, while the cost of physiological resistance accrues only to the individual. Further, resistance, and the associated reduction in transmission, benefit susceptible hosts directly, whereas infected hosts only benefit indirectly, by reducing transmission to kin. We therefore model the coevolution of transmission-reducing resistance expressed in susceptible hosts with resistance expressed in infected hosts, as a function of kin association, and analyse the effect on population-level outcomes. Using parameter values for guppies, Poecilia reticulata, and their gyrodactylid parasites, we find that: (1) either susceptible or infected hosts should invest heavily in resistance, but not both; (2) kin association drives investment in physiological resistance more strongly than in behavioural resistance; and (3) even weak levels of kin association can favour altruistic infected hosts that invest heavily in resistance (versus selfish tolerance), eliminating parasites. Overall, our finding that weak kin association affects the coevolution of infected and susceptible investment in both behavioural and physiological resistance suggests that kin selection may affect disease dynamics across systems.

Evolutionary Rate Shifts in Coding and Regulatory Regions Underpin Repeated Adaptation to Sulfidic Streams in Poeciliid Fishes.

Adaptation to extreme environments often involves the evolution of dramatic physiological changes. To better understand how organisms evolve these complex phenotypic changes, the repeatability and predictability of evolution, and possible constraints on adapting to an extreme environment, it is important to understand how adaptive variation has evolved. Poeciliid fishes represent a particularly fruitful study system for investigations of adaptation to extreme environments due to their repeated colonization of toxic hydrogen sulfide-rich springs across multiple species within the clade. Previous investigations have highlighted changes in the physiology and gene expression in specific species that are thought to facilitate adaptation to hydrogen sulfide-rich springs. However, the presence of adaptive nucleotide variation in coding and regulatory regions and the degree to which convergent evolution has shaped the genomic regions underpinning sulfide tolerance across taxa are unknown. By sampling across seven independent lineages in which nonsulfidic lineages have colonized and adapted to sulfide springs, we reveal signatures of shared evolutionary rate shifts across the genome. We found evidence of genes, promoters, and putative enhancer regions associated with both increased and decreased convergent evolutionary rate shifts in hydrogen sulfide-adapted lineages. Our analysis highlights convergent evolutionary rate shifts in sulfidic lineages associated with the modulation of endogenous hydrogen sulfide production and hydrogen sulfide detoxification. We also found that regions with shifted evolutionary rates in sulfide spring fishes more often exhibited convergent shifts in either the coding region or the regulatory sequence of a given gene, rather than both.

Infection of guppies (Poecilia reticulata) with the Asian fish tapeworm Schyzocotyle acheilognathi in an urban stream in Brazil.

Schyzocotyle acheilognathi is a fish tapeworm native to Asia but has been reported as an alien species on practically all other continents. Its invasive potential is due to its low host specificity and high adaptability to different environments, and its spread to new areas can result in economic and ecological impacts. Studies reporting this species in South America are still scarce, indicating the need to monitor its dispersion to new areas. Herein, tapeworms found in guppies, Poecilia reticulata, from an urban stream located in Belo Horizonte, Minas Gerais, Brazil, in April 2021 were subjected to morphological and molecular characterization. As a result, 5/13 (38.5%) of the P. reticulata specimens evaluated were infected with intestinal tapeworms. It was verified a mean intensity of infection of 7.8 (1-25) and a mean abundance of infection of 3 (0-25). The morphology of the cestodes obtained was compatible with that of S. acheilognathi. Moreover, genetic analysis based on cytochrome c oxidase subunit 1 gene (Cox-1) revealed 97.89-99.77% similarity to isolates of this species from different localities. The possibility that S. acheilognathi is expanding to new regions of South America is discussed.

Evolutionary divergence of plasticity in brain morphology between ecologically divergent habitats of Trinidadian guppies.

Phenotypic plasticity is critical for organismal performance and can evolve in response to natural selection. Brain morphology is often developmentally plastic, affecting animal performance in a variety of contexts. However, the degree to which the plasticity of brain morphology evolves has rarely been explored. Here, we use Trinidadian guppies (Poecilia reticulata), which are known for their repeated adaptation to high-predation (HP) and low-predation (LP) environments, to examine the evolution and plasticity of brain morphology. We exposed second-generation offspring of individuals from HP and LP sites to 2 different treatments: predation cues and conspecific social environment. Results show that LP guppies had greater plasticity in brain morphology compared to their ancestral HP population, suggesting that plasticity can evolve in response to environmentally divergent habitats. We also show sexual dimorphism in the plasticity of brain morphology, highlighting the importance of considering sex-specific variation in adaptive diversification. Overall, these results may suggest the evolution of brain morphology plasticity as an important mechanism that allows for ecological diversification and adaptation to divergent habitats.

Transversotrema hafniensis n. sp. infection in Poecilia reticulata by cercariae released from Melanoides tuberculata in Denmark.

BACKGROUND: Exotic and ornamental fish are highly popular companion animals resulting in a significant transcontinental trade of fish, invertebrates and aquatic plants. A major issue is the diseases associated with these organisms, as they have a major impact on health of the fish in both public and private household aquaria. A secondary issue is the trade with these products, which potentially may expand the distribution area and spread a range of diseases to new habitats. RESULTS: We here describe how Poecilia reticulata (guppy), produced in a private household aquarium, were invaded by cercariae of an exotic trematode released by imported Melanoides tuberculata snails. The fish presented with severe clinical signs (tremor, flashing, scraping of body against objects). A standard parasitological examination and morphometric identification showed scale pocket infections with a digenean trematode species within the genus Transversotrema. Molecular identification by PCR, sequencing and phylogenetic analyses of a 2646 bp sequence encoding ribosomal RNA (partial 18 S, ITS1, 5.8 S, ITS2, partial 28 S) was performed. The 1107 bp sequence of mitochondrial DNA (cox1) showed that the parasite differed from previously described Transversotrema species in M. tuberculata. Morphometrics of adult and larval specimens of this isolate also differed from previously described freshwater species within the genus. The new species was described and is named after Copenhagen, for its geographic origin. CONCLUSIONS: The genus Transversotrema comprises a range of species, adapted to a microhabitat in scalepockets of teleosts. A combination of morphological and molecular characterization techniques has been shown to provide a good differentiation between species. The fish were not purchased from a pet shop but produced in the home aquarium. This indicated that an infection pressure existed in the aquarium, where the source of infection was found to be exotic intermediate host snails M. tuberculata, which originally were imported and purchased from a pet shop. The potential spread of fish diseases associated with trade of fish and snails to new geographic regions, where climate conditions are favourable, is discussed.

Disentangling genetic, plastic and social learning drivers of sex-specific foraging behaviour in Trinidadian guppies (Poecilia reticulata).

Evolutionary biologists have long been interested in parsing out the roles of genetics, plasticity and their interaction on adaptive trait divergence. Since males and females often have different ecological and reproductive roles, separating how their traits are shaped by interactions between their genes and environment is necessary and important. Here, we disentangle the sex-specific effects of genetic divergence, developmental plasticity, social learning and contextual plasticity on foraging behaviour in Trinidadian guppies (Poecilia reticulata) adapted to high- or low-predation habitats. We reared second-generation siblings from both predation regimes with or without predator chemical cues, and with adult conspecifics from either high- or low-predation habitats. We then quantified their foraging behaviour in water with and without predator chemical cues. We found that high-predation guppies forage more efficiently than low-predation guppies, but this behavioural difference is context-dependent and shaped by different mechanisms in males and females. Higher foraging efficiency in high-predation females is largely genetically determined, and to a smaller extent socially learned from conspecifics. However, in high-predation males, higher foraging efficiency is plastically induced by predator cues during development. Our study demonstrates sex-specific differences in genetic versus plastic responses in foraging behaviour, a trait of significance in organismal fitness and ecosystem dynamics.

Diagnosis, isolation and description of a novel amnoonvirus recovered from diseased fancy guppies, Poecilia reticulata.

The guppy, Poecilia reticulata, is one of the most common cultured ornamental fish species, and a popular pet fish highly desired by hobbyists worldwide due to its availability of many brilliantly coloured fish of many varieties. The susceptibility of guppies to diseases presents a remarkable concern for both breeders and hobbyists. In this study, we report the emergence of disease in fancy guppies caused by a previously uncharacterized virus in the USA. This virus was isolated from moribund guppies in two separate outbreaks in California and Alabama, from December 2021 to June 2023. The infected guppies presented with acute morbidity and mortality shortly after shipping, displaying nonspecific clinical signs and gross changes including lethargy, anorexia, swimming at the water surface, gill pallor, mild to moderate coelomic distension and occasional skin lesions including protruding scales, skin ulcers and hyperaemia. Histological changes in affected fish were mild and nonspecific; however, liver and testes from moribund fish were positive for Tilapia lake virus (TiLV), the single described member in the family Amnoonviridae, using immunohistochemistry and in situ hybridization, although the latter was weak. A virus was successfully recovered following tissue inoculation on epithelioma papulosum cyprini and snakehead fish cell lines. Whole genome sequencing and phylogenetic analyses revealed nucleotide and amino acid homologies from 78.3%-91.2%, and 78.2%-97.7%, respectively, when comparing the guppy virus genomes to TiLV isolates. Based on the criteria outlined herein, we propose the classification of this new virus, fancy tailed guppy virus (FTGV), as a member of the family Amnoonviridae, with the name Tilapinevirus poikilos (from the Greek 'poikilos', meaning of many colours; various sorts, akin to 'poecilia').

Insights into adaptive behavioural plasticity from the guppy model system.

Behavioural plasticity allows organisms to respond to environmental challenges on short time scales. But what are the ecological and evolutionary processes that underlie behavioural plasticity? The answer to this question is complex and requires experimental dissection of the physiological, neural and molecular mechanisms contributing to behavioural plasticity as well as an understanding of the ecological and evolutionary contexts under which behavioural plasticity is adaptive. Here, we discuss key insights that research with Trinidadian guppies has provided on the underpinnings of adaptive behavioural plasticity. First, we present evidence that guppies exhibit contextual, developmental and transgenerational behavioural plasticity. Next, we review work on behavioural plasticity in guppies spanning three ecological contexts (predation, parasitism and turbidity) and three underlying mechanisms (endocrinological, neurobiological and genetic). Finally, we provide three outstanding questions that could leverage guppies further as a study system and give suggestions for how this research could be done. Research on behavioural plasticity in guppies has provided, and will continue to provide, a valuable opportunity to improve understanding of the ecological and evolutionary causes and consequences of behavioural plasticity.

Aesthetic preference for artificially selected color variant affects mate choice copying behavior in female Poecilia latipinna.

Three experiments were conducted examining whether an artificially selected "gold" color variant in female "models" affects mate choice copying behavior in sailfin mollies (Poecilia latipinna). Experiment I consisted of a pair of female preference assays, first assessing preference for male body size, followed by a mate choice copying assay that paired a model female with the smaller, non-preferred male from the initial preference test. Female subjects were divided into three groups that used either a wildtype female model, an artificially selected "gold" variant (cultivated within the aquarium fish trade) model, or control wherein no model was presented. Results showed females consistently copied the model's choice, switching preferences from the larger to smaller male when paired with a model regardless of color. In the second experiment wildtype females were presented with a pair of size-matched dummy males both of which paired with model females (one gold and the other wild type). Subjects consistently preferred the male previously paired with the gold- over the male with the wildtype-model, suggesting pre-existing sensory/perceptual biases may have affected their mate choice copying behavior. Previous studies have offered evidence for the spread of novel traits in males via sensory exploitation. However, these results indicate such biases may influence courtship behavior in circumstances where the novel trait is expressed in females as well. For the third experiment, wildtype females were presented with a choice between gold vs wildtype dummy males, the results of which revealing significant preferences for gold. In a follow-up assay pairing a wild type model with the non-preferred wildtype male, females maintained their preference for gold males despite the conflicting social driver of mate choice copying. These data offer evidence for the existence of a perceptual/cognitive bias in the context of mate choice copying, favoring the gold phenotype and/or novelty in general.

New xenophyophores (Foraminifera, Monothalamea) from the eastern Clarion-Clipperton Zone (equatorial Pacific).

Xenophyophores are large, agglutinated foraminifera that dominate the benthic megafauna in some parts of the deep sea. Here, we describe an assemblage of largely fragmentary specimens from the Clarion-Clipperton Zone (CCZ), an area of the eastern abyssal Pacific hosting large, commercially significant deposits of polymetallic nodules. We recognised 18 morphospecies of which eight yielded DNA sequences. These include two new genera and three new species, Claraclippia seminuda gen. & sp. nov., Stereodiktyoma mollis gen. & sp. nov., and Aschemonella tani sp. nov., three that are assigned to known species, Abyssalia foliformis, Aschemonella monilis and Shinkaiya contorta, and two assigned to open nomenclature forms Abyssalia aff. foliformis and Stannophyllum aff. granularium. An additional ten forms are represented only by morphology. The following seven are placed in known genera, species and open-nomenclature forms: Aschemonella? sp., Homogammina sp., Psammina multiloculata, P. aff. multiloculata, P. aff. limbata form 1 sensu Gooday et al., 2018, P. aff. limbata form 2 sensu Gooday et al., 2018, and Stannophyllum spp. The other three could not be identified to genus level. This new collection brings the total of described and undescribed species and morphotypes from the CCZ to 27 and 70, respectively, reinforcing the already high diversity of xenophyophores known from this part of the Pacific.

Antiparasitic efficacy of flavonoids identified from Psoralea corylifolia against Tetrahymena piriformis in guppy (Poecilia reticulate).

Tetrahymena piriformis belongs to the ciliated protists (ciliates), causing severe economic losses in aquaculture. Chemical drugs currently used usually have toxic side effects, and there is no specific drug against Tetrahymena. Therefore, it is an urgent need to identify new antiparasitic lead compounds. In the present study, the in vitro parasiticidal activity of ethyl acetate (EtOAc) extracts and water extracts from 22 selected traditional Chinese medicines (TCMs) were evaluated against T. piriformis. The EtOAc extract of P. corylifolia turned out to be the most active with the minimum parasiticidal concentration of 100 mg/L within 3 h. Thus, it was separated into 12 fractions by the first-dimensional (D1) normal phase liquid chromatography (NPLC), meanwhile combining with in vitro antiparasitic tests for activity tracking. Subsequently, 8 flavonoids were identified in the active fractions by the second-dimensional (D2) reverse phase liquid chromatography (RPLC) tandem high-resolution mass spectrometry. According to the results, 5 flavonoids were selected for in vitro antiparasitic test, of which isobavachalcone showed the minimum parasiticidal concentration of 3.125 mg/L in 2 h. Bathing treatment of infected guppies with isobavachalcone could significantly reduce the burden of T. piriformis, obtaining a 24-h median effective concentration (24-h EC50) value of 1.916 mg/L. And the concentration of isobavachalcone causing guppies to die within 24 h is 39 times than that of 24-h EC50. The results demonstrated that isobavachalcone has the potential to be developed into a novel commercial fish drug against T. piriformis.

2023 ASHG Scientific Achievement Award: Molly Przeworski.

This article is based on the address given by the author at the 2023 meeting of The American Society of Human Genetics (ASHG) in Washington, D.C. The video of the original address can be found at the ASHG website.