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G3: Genes, Genomes, Genetics

Oxford University Press (OUP)

Preprints posted in the last 30 days, ranked by how well they match G3: Genes, Genomes, Genetics's content profile, based on 252 papers previously published here. The average preprint has a 0.20% match score for this journal, so anything above that is already an above-average fit.

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Gene model for the ortholog of tgo in Drosophila busckii

Perez, J.; Giunta, A. A.; Wittke-Thompson, J. K.

2026-07-01 genomics 10.64898/2026.06.26.734908 medRxiv
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Gene model for the ortholog of tango (tgo) in the Sep. 2015 (UC Berkeley ASM127793v1/DbusGB1) Genome Assembly (GenBank Accession: GCA_001277935.1) of Drosophila busckii. This ortholog was characterized as part of a developing dataset to study the evolution of the Insulin/insulin-like growth factor signaling pathway (IIS) across the genus Drosophila using the Genomics Education Partnership gene annotation protocol for Course-based Undergraduate Research Experiences.

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A recombinant dilp2GS-rpr donor line for adult-inducible IPC ablation across Drosophila genetic backgrounds

Chen, Y.; Bai, Y.; Zhuang, X.

2026-06-22 genetics 10.64898/2026.06.17.733056 medRxiv
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Genetic-background studies require defined perturbations that can be crossed reproducibly into many recipient backgrounds. We generated a Drosophila dilp2GS-rpr donor line for adult-inducible ablation of insulin-producing cells (IPCs), which secrete insulin-like peptides and provide a tractable model of insulin-deficient metabolic physiology. This line carries dilp2-GeneSwitch-GAL4 and UAS-reaper in cis on the same second chromosome homolog over a balancer. PCR genotyping and sequencing confirmed both transgenic elements in the candidate recombinant line. RU486 induction reduced dilp2 mRNA expression, supporting partial IPC ablation. Treatment-duration testing identified 8 days of RU486 as sufficient to increase whole-body glucose in the dilp2GS-rpr line but not in the background-matched control; food intake did not differ between RU486- and vehicle-treated flies. Across metabolic assays, whole-body glucose showed the clearest RU486- and line-dependent phenotype. This validated dilp2GS-rpr line enables testing how recipient genetic backgrounds modify inducible IPC/DILP metabolic phenotypes and provides a framework for similar linked donor-line resources.

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Gene model for the ortholog of raptor in Drosophila grimshawi

Lieser, B. C.; Lose, B.; Kiser, C. A.; Butterfield, S.; Laschober, L.; Laskowski, L. F.; Nielsen, J.; Pulford, J.; Thompson, J. S.; Rele, C. P.; Wittke-Thompson, J. K.

2026-07-11 genomics 10.64898/2026.07.07.737051 medRxiv
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Gene model for the ortholog of raptor in the D. grimshawi May 2011 (Agencourt dgri_caf1/DgriCAF1) Genome Assembly (GenBank Accession: GCA_000005155.1) of Drosophila grimshawi. This ortholog was characterized as part of a developing dataset to study the evolution of the Insulin/insulin-like growth factor signaling pathway (IIS) across the genus Drosophila using the Genomics Education Partnership gene annotation protocol for Course-based Undergraduate Research Experiences.

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Gene model for the ortholog of raptor in Drosophila erecta

Backlund, A. E.; Nielsen, J.; Pulford, J.; Cook, B.; Anderson, J.; Robert, M.; Thompson, J. S.; Rele, C. P.; Wittke-Thompson, J. K.

2026-07-14 genomics 10.64898/2026.07.09.737526 medRxiv
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Gene model for the ortholog of raptor in the May 2011 (Agencourt Dere_CAF1/DereCAF1) Genome Assembly (GenBank Accession: GCA_000005135.1) of Drosophila erecta. This ortholog was characterized as part of a developing dataset to study the evolution of the Insulin/insulin-like growth factor signaling pathway (IIS) across the genus Drosophila using the Genomics Education Partnership gene annotation protocol for Course-based Undergraduate Research Experiences.

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Comparative Analysis of Transposable Elements in Hermetia illucens

Hector Rosche-Flores, H.; Fischer, S.; Picard, C. J.

2026-07-11 genomics 10.64898/2026.07.10.737754 medRxiv
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BackgroundThe black soldier fly (Hermetia illucens) is an emerging model for bioconversion and industrial rearing. Its genome is highly repetitive, yet the contribution of transposable elements (TEs) to population divergence and demographic processes. The sampled populations represent a gradient of demographic histories, including wild and near-wild North American populations, and domesticated European strains with shared industrial origins. Difference in TE composition may influence genome structure, regulatory variation, and evolutionary responses to captive environments. ResultsA comparative analysis of the repetitive landscape was done for four H. illucens genomes, one of which is a wild-caught specimen. Total repeat content was high across all assemblies (67.6% to 70.8%) and dominated by LINE elements. Class-level TE diversity was nearly identical among genomes, but multiple DNA transposon families showed distinct lineage-specific differences. Large families including Maverick and Academ were generally depleted relative to the wild sample. Divergence profiles revealed patterns consistent with recent turnover in several families. Family level turnover, rather than class level change, accounted for the most difference among the genomes. TE-associated structural variants (TESVs) were also not uniformly distributed. Most chromosomes showed mid-chromosome enrichment, and a pronounced TESV peak on chromosome 5 overlapped a histone rich region containing many unclassified repeats. Use of a repeat library derived from multiple genomes increased the number of detected TESVs and improved classification within complex regions, demonstrating that multi-genome libraries enhance annotation accuracy compared to single reference-based models. ConclusionsMultiple DNA transposon families show evidence of recent or lineage-specific amplification in H. illucens, suggesting that TE amplification contributes to genome variation during demography-associated TE turnover. The multi-genome-based library improved TE detection and classification, providing a proof of concept that even a small lineage-inclusive repeat library enhances annotation accuracy and capture TE diversity missed by single-reference approaches. Together, these findings demonstrate that TE family turnover plays a significant role in shaping genome architecture and adaptation in this species.

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A chromosome-level genome assembly of the Eurasian great grey owl, Strix nebulosa lapponica (Thunberg 1798)

Strand, M. A.; Steindal, I. A. F.; Ragnhildstveit, E.; Solheim, R.; Torresen, O. K.; Skage, M.; Ferrari, G.; Tooming-Klunderud, A.; Jakobsen, K. S.

2026-07-02 genomics 10.64898/2026.06.29.735218 medRxiv
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We present a chromosome-level genome assembly of a female great grey owl (Strix nebulosa lapponica). The assembly comprises two pseudo-haplotypes of 1554 Mb and 1242 Mb, with 83.2% and 91.4% scaffolded into 40 autosomal chromosomes, in addition to the W and Z sex chromosomes both placed in hap1. Assembly completeness is high (BUSCO 99.2% and 94.8%), with 18,493 and 17,279 annotated protein-coding genes for hap1 and hap2, respectively. This genome establishes a reference for investigating genetic variation and chromosome evolution in great grey owls. Compared with the previous S. nebulosa assembly, this assembly includes both sex chromosomes, separates regions that were previously collapsed, and resolves 82 chromosomes total. While larger chromosomes show broadly conserved synteny across owl assemblies, the recovery of additional conserved microchromosome-associated genes suggests that ONT reads improved resolution of the smallest chromosomes relative to HiFi-based assemblies.

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Knock-in = knock-out: differential fitness effects of cardinal mutations in Anopheles stephensi

Larrosa-Godall, M.; Shackleford, L.; Leftwich, P. T.; Gonzalez, E.; Ang, J. X.; Edwards, M.; Nevard, K.; Luk, J. C. Y.; Mckee, M.; Noad, R.; Anderson, M.; Alphey, L.

2026-07-09 genetics 10.64898/2026.07.07.737011 medRxiv
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The kynurenine pathway metabolizes tryptophan into 3-hydroxykynurenine (3-HK), a precursor for ommochrome eye pigments synthesized via the cardinal (cd) gene in mosquitoes. While cd disruption was presumed neutral, we observed fitness costs in Anopheles stephensi knock-in but not knock-out cd mutants. Here we investigated this anomaly further by assessing survival, fecundity, and midgut integrity across multiple cd mutant lines. Heterozygous knock-in lines, expressing a fluorescent marker and guide RNA for CRISPR/Cas9, exhibited reduced survival post-blood feeding, larva-to-adult survival deficits, and midgut barrier dysfunction, whereas knock-outs showed no such costs. Oral supplementation with xanthurenic acid partially rescued knock-in mortality, implicating oxidative stress linked to 3-HK metabolism. Expression analyses suggest transgene insertion effects, rather than cd disruption, underlie these fitness costs. These findings highlight the importance of evaluating insertional effects in gene drive target selection and support cd as a viable target for genetic control strategies in An. stephensi.

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Gene model for the ortholog of DENR in Drosophila eugracilis

Lawson, M. E.; Sanow, K. A.; Martinand, I.; Fratian, M.; Matura, M.; Rele, C. P.; Reed, L. K.; Thompson, J. S.; O'Rourke, K. S.

2026-06-26 genomics 10.64898/2026.06.23.734050 medRxiv
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Gene model for the ortholog of Density regulated protein (DENR) in the Apr. 2013 (BCM-HGSC/Deug_2.0) (DeugGB2) Genome Assembly (GenBank Accession: GCA_000236325.2) of D. eugracilis. This ortholog was characterized as part of a developing dataset to study the evolution of the Insulin/insulin-like growth factor signaling pathway (IIS) across the genus Drosophila using the Genomics Education Partnership gene annotation protocol for Course-based Undergraduate Research Experiences.

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Paralogs of the <em>Candida albicans TLO</em> gene family form interconnected functional networks with incomplete redundancy

Simonton, E.; Cangelosi, N.; Zhou, M.; Hendricks, P. S.; Woodruff, A. L.; Anderson, M. Z.

2026-07-02 genetics 10.64898/2026.06.29.735307 medRxiv
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Gene duplication typically fails to confer a selective advantage to an organism, prompting their removal from a population. In the rare instance that duplication either does not incur a fitness cost or it enhances fitness, gene families can form through repeating the duplication process. While the function of gene duplicates has been studied in detail, little work has explored how repeated duplication impacts paralog redundancy and may restrict the emergence of new paralogs or novel function. Here, we constructed a panel of single deletion mutants for each of the 14 members of the <em>Candida albicans</em> telomere-associated (<em>TLO</em>) gene family to test the redundancy in molecular and biological function among paralogs from a lineage-specific expansion. Tlo proteins function as interchangeable subunits of the Mediator transcriptional regulatory complex and have the potential to alter gene expression and an array of cellular responses. Redundancy was the most common outcome, being observed for approximately 80% of the phenotypic assays in strains lacking single <em>TLO </em>genes. However, mutants for all 14 paralogs displayed non-redundant functions in phenotypes ranging from carbon utilization to <em>in vivo</em> virulence. Analysis of gene expression in single <em>TLO </em>mutants found similar trends in redundancy, and loss of single <em>TLO</em>s disproportionately affected genes involved in filamentation, adhesion, redox reactions, and transporter activity at the cell surface. Importantly, sequence divergence between paralogs positively correlated with the frequency of altered phenotypes in single <em>TLO </em>mutants, indicating the acquisition of non-redundant function with increased evolutionary distance. Double mutants lacking two <em>TLO</em> genes produced both positive and negative synergistic phenotypes, suggesting that crosstalk or coordinated regulation is common among paralogs. Together, this study demonstrates that recently emergent paralogs acquire non-redundant functions despite often retaining redundancy with other gene family members to form a highly interconnected functional network.

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The impact of P-Element-induced hybrid dysgenesis on the male germline in Drosophila simulans

Griffin, J. S.; Harney, E.; Capes, C.; Connell, R.; Betancourt, A. J.; Romero-Soriano, V.

2026-07-01 genetics 10.64898/2026.06.28.735054 medRxiv
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The P-element, a DNA transposon, has independently invaded two Drosophila species, accompanied by rapid evolution of suppression. In the germline, suppression is mediated primarily by maternally expressed piRNAs, a class of regulatory small RNAs associated with PIWI proteins. The offspring of females that lack P-element-specific piRNAs and males that contain P-elements suffer a syndrome of deleterious phenotypes, including sterility, genome rearrangements, gonadal atrophy, and mutations, while the offspring of the reciprocal cross are normal. These effects, collectively termed hybrid dysgenesis, have been investigated primarily in female D. melanogaster. Here, we study hybrid dysgenesis in male D. simulans. Using an attached-X chromosome stock, we generated genetically identical F1 males that differed only in maternal suppression of the P-element. Using targeted sequencing of P-element breakpoints, we show that P-element transposition is elevated in dysgenic males and confirm a preference for insertion near origins of replication. Using transcriptomics, we show that dysgenic males have elevated P-element expression and reduced splicing suppression, with patterns of gene expression suggesting the loss of mature sperm cells. Fertility assays show higher rates of male sterility but otherwise modest effects on fertility. In conjunction with the transcriptomic data, small RNA sequencing confirms that the piRNA pathway functions in testes. Our results suggest that the P-element may spread more readily through males than females, as transposition rates are similar while fertility defects are less severe in males.

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Driver-independent lexAop-tdTomato.nls reporter signal in the adult Drosophila proventriculus

Zhou, X.; Zhang, T.; Kim, W. J.

2026-07-11 genetics 10.64898/2026.07.07.737111 medRxiv
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Reporters are widely used in Drosophila genetics to visualize gene expression and cell lineages. However, uncharacterized limitations in specific reporter lines can lead to data misinterpretation. Here, we identify a consistent, driver-independent tdTomato signal in the adult proventriculus from the widely used lexAop-tdTomato.nls reporter line. This signal was observed across multiple lexA driver combinations and was directly detectable in lexAop-tdTomato.nls responder-alone adult proventriculi lacking any lexA driver and without antibody staining. In contrast, no comparable native red fluorescence was detected in larval proventriculi under the same no-antibody imaging condition. Mouse and rabbit anti-RFP immunostaining further supported the presence of proventriculus-associated tdTomato/RFP antigen in adult responder-alone animals. In larval responder-alone proventriculi, antibody-amplified staining was antibody-source-dependent: a detectable signal was observed only with rabbit anti-RFP, whereas mouse and rat anti-RFP produced no reliable detectable signal under the same staining condition. A driver-matched comparison using lexAop-RFP.nls did not reproduce the proventricular signal, arguing against detectable ectopic activity of the tested lexA driver in this tissue. However, because lexAop-tdTomato.nls and lexAop-RFP.nls differ in reporter/transgene architecture and possibly genomic insertion context, the underlying cause cannot be assigned specifically to the lexAop sequence. Our findings highlight the necessity of including driver-negative and no-antibody controls when using this reporter line in adult Drosophila proventriculus and gut studies.

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Novel Drosophila cis-regulatory elements can be uncovered by footprinting transcription factor binding sites in ATAC-seq data

Mei, C.; Ness, J.; Nakai, K.; Wunderlich, Z.

2026-06-25 genomics 10.64898/2026.06.22.733832 medRxiv
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Developmental processes depend on carefully coordinated gene expression. Expression is modulated by the binding of transcription factors (TFs) to cis-regulatory elements (CREs), like enhancers and promoters. Many computational and experimental approaches have been developed to find CREs, particularly enhancers, in the genome, each with strengths and caveats. Given the increasing availability of ATAC-seq data and methods to find TF binding therein, we hypothesized that we could use TF footprinting tools to find clusters of TF binding events within accessible chromatin that may act as CREs. Using Drosophila anterior-posterior patterning network as a test bed, we used a digital genomic footprinting tool (DGT), TOBIAS, on previously published early embryo ATAC-seq data to characterize the TF footprint landscape of 16 TFs essential for embryonic patterning. Even in this system, with its extensive enhancer annotation, most footprinted TF binding sites lie outside of known enhancers, with intergenic and intronic regions hosting the highest TF footprint count, albeit at low density. To find potential novel enhancers, we identified high-density TF footprint clusters that are highly conserved and overlap with active enhancer histone mark signals. Five high confidence candidates were selected for reporter assay validation and all five were found to drive spatially patterned expression in the embryo. This study shows that even in a highly characterized system, the analysis of footprinted TF binding sites in ATAC-seq data can uncover new regulatory regions and suggests this approach may be helpful in using existing ATAC-seq data to find novel CREs. ARTICLE SUMMARYGiven the increasing availability of ATAC-seq datasets, workflows to exploit the data to uncover new cis-regulatory elements (CREs), including enhancers, are valuable. Using early anterior-posterior patterning in the Drosophila embryo as a test case, we find that previously published transcription factor footprinting tools and ATAC-seq data can be analyzed to yield new candidate CREs. Experimental validation confirms the activity of selected candidate CREs, suggesting that existing data can be analyzed to find novel regulatory elements.

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Integrated pangenome and population genomics reveal selection on standing genetic variation driving fiber flax-linseed divergence

You, F. M.; Zheng, C.; Edwards, T.; Li, P.; Rashid, K. Y.; Duguid, S. D.; Booker, H.; Cloutier, S.

2026-07-14 genomics 10.64898/2026.07.09.737549 medRxiv
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Flax (Linum usitatissimum L.) has been domesticated for dual end uses as linseed and fiber flax, yet the genomic basis of morphotype divergence remains unclear. Here, we constructed a morphotype-resolved pangenome by integrating three newly generated near telomere-to-telomere genome assemblies with 14 previously published ones. Despite substantial variation in assembly size, driven primarily by DNA transposons, gene content was highly conserved, with little evidence for significant morphotype-specific gene presence-absence variation. Population genomic analyses of 407 accessions revealed that fiber flax had reduced nucleotide diversity, extended linkage disequilibrium, and a more compact population structure relative to linseed, consistent with stronger selection and a narrower genetic base. Genome-wide differentiation was heterogeneous and concentrated in discrete regions. Integration of FST, nucleotide diversity ratios, Tajimas D, and genome-wide association signals identified morphotype-enriched genomic blocks distributed across the genome. Many candidate regions are primarily supported by directional shifts in nucleotide diversity rather than extreme differentiation, indicating selection on standing genetic variation. Genome-wide association analyses identified 1,712 unique quantitative trait nucleotides (QTNs), with predominantly small effect sizes and strong enrichment in gene-proximal regions, consistent with a polygenic architecture. Overall, fiber flax traits tend to be controlled by fewer loci with moderate-to-large effects, whereas linseed traits exhibit a more diffuse genetic architecture. Patterns of Tajimas D further support non-classical selection dynamics, with predominantly positive values in linseed and localized negative values in fiber flax, consistent with selection on standing genetic variation. Together, our results suggest that flax morphotype divergence is driven primarily by selection on pre-existing allelic variation within a conserved gene repertoire. This study provides a comprehensive framework linking genome structure, population genomics, and trait architecture, and highlights the importance of standing genetic variation as a key resource for flax breeding and improvement.

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Female genetic variation controlling timing of mating plug ejection in Drosophila melanogaster

Carlisle, J. A.; Craig, R. M. J.; Matera-Vatnick, M.; Villanuenva, B. M.; Andrus, A. R.; Cosgrove, E. J.; Chen, D. S.; Clark, A. G.; Wolfner, M. F.

2026-07-01 genetics 10.64898/2026.06.27.734984 medRxiv
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In multiply-mating species, male-female postcopulatory, prezygotic interactions can influence reproductive outcomes. In Drosophila melanogaster, females can bias sperm storage and usage and thereby influence paternity outcomes. One mechanism by which females may regulate paternity contributions from specific males is through modulation of mating plug ejection timing. The D. melanogaster mating plug is composed of seminal fluid proteins, and some female-derived proteins, that coagulate in the female reproductive tract during mating. The mating plug facilitates sperm storage; thus, timing of female mating plug ejection is associated with sperm storage and relative paternity contributions in cases of multiple mating. However, whether there is natural genetic variation among females that shapes mating plug ejection timing, and genes or phenomena that might mediate it are unknown. We examined mating plug ejection in females from 69 lines of the Drosophila Genetic Reference Panel and observed dramatic differences in median plug ejection timing ranging from less than 1 to over 6 hours. We used this variation to perform a genome-wide association study to identify gene candidates associated with this phenotype. Many gene candidates are expressed in the brain and/or function in neurodevelopment. The candidate pool was also enriched for genes expressed in the ovary and functioning in oogenesis, indicating a link between female reproductive physiology and mating plug ejection. Consistent with this interpretation, females without a germline delay mating plug ejection. Our results demonstrate that female mating plug ejection is a physiologically integrated reproductive trait with a genetic basis that can be shaped by selection. Article SummaryThe D. melanogaster mating plug is composed of seminal fluid proteins and some female-derived proteins that coagulate in the female reproductive tract during mating. The mating plug facilitates sperm storage; thus, timing of female mating plug ejection is associated with sperm storage and relative paternity contributions in cases of multiple mating. Using the DGRP, we observed heritable genetic variation in female timing of mating plug ejection and through a GWAS find associated gene candidates. Gene candidates are enriched for neurodevelopment function and oogenesis function. We experimentally validate the connection between female mating plug ejection and the ovary.

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Drosophila beanbag (beba) encodes a novel insect receptor tyrosine kinase associated with reproductive niche organisation

Mele, S.; Bright, S.; Kerton, E.; Johnson, T. K.

2026-07-10 genetics 10.64898/2026.07.06.736846 medRxiv
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Receptor tyrosine kinases (RTKs) are cell surface proteins that govern many critical cell fate decisions and their dysregulation is a major cause of diseases such as cancer. Much of what we know about how these proteins work in cells and tissues comes from model organisms such as the fruit fly Drosophila. Here, we identify and characterise a previously unstudied Drosophila receptor tyrosine kinase encoded by CG3277, which we name beanbag (beba). Ectopic beba expression activated Akt and ERK phosphorylation and produced gain-of-function phenotypes resembling those caused by other Drosophila RTKs. Using a MiMIC-derived T2A-GAL4 allele, we show that Drosophila beba is expressed in digestive, nervous and reproductive systems, in locations suggestive of potential roles in endoreplication and/or stem cell niche support. Animals transheterozygous for beba loss-of-function alleles were viable, developed at a normal rate, and showed no detectable change in enterocyte DNA content under standard conditions. However, beba loss-of-function females had fewer ovarioles, consistent with a role in the ovarian terminal filament, and males had increased testis hub cell number and hub volume, suggesting beba may regulate somatic niche architecture in the Drosophila gonad. Phylogenetic analysis places Beba within a Ret/Tor-related RTK radiation and supports the existence of a distinct Beba family in insects. Together, our data define Beba as a lineage-restricted Drosophila RTK with specialised roles in reproductive niche organisation.

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Repair outcomes after germline homing endonuclease cleavage in Anopheles gambiae inform the design of synthetic gene drives

Naujoks, D.; Nolan, T.

2026-06-23 genetics 10.64898/2026.06.23.733901 medRxiv
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Homing endonuclease genes spread by cleaving homologous chromosomes that lack the endonuclease cassette, after which repair from the endonuclease-containing chromosome converts the cut allele into a copy of the drive allele. This mechanism has provided a conceptual foundation for synthetic gene drive systems, including CRISPR-based drives, that represent promising strategies for the genetic control of insect pests. However gene drive performance depends critically on the repair pathways available in the germline of the target organism. Here, we report a set of transgenic assays originally developed as part of an attempt to establish gene targeting in the malaria mosquito Anopheles gambiae using an in vivo-generated linear targeting molecule. Although the intended FLP-mediated excision step was not achieved in the mosquito germline, analysis of the component strains revealed efficient germline activity of the rare-cutting homing endonuclease I-SceI and a striking bias towards homology-based repair of I-SceI-induced double-strand breaks. Across reporter and donor configurations, cleavage outcomes were dominated by single-strand annealing, microhomology-mediated repair, synthesis-dependent strand annealing and gene conversion-like events, with comparatively limited evidence for classical non-homologous end joining. In reciprocal crosses designed to distinguish gene conversion from gamete loss, I-SceI cleavage also produced inheritance distortion consistent with both conversion of the cleaved allele and reduced recovery of gametes carrying extensively damaged donor alleles. These findings indicate that the An. gambiae germline can strongly favour homology-dependent repair following homing endonuclease cleavage and that cleavage can also generate meiotic drive-like distortion through selective loss of damaged gametes. The results have direct relevance for the design and interpretation of homing endonuclease and CRISPR-based gene drives in malaria mosquitoes, where the balance between homology-directed repair, end joining and gamete viability will determine drive efficiency, resistance formation and transmission bias. Author summaryGene drives depend on a simple but demanding principle: a nuclease cuts one chromosome, and the cell repairs the break using the homologous chromosome as a template, copying the drive element in the process. Before CRISPR, this type of system was explored using naturally occurring homing endonucleases such as I-SceI. We attempted to develop a gene targeting system in Anopheles gambiae based on the Rong and Golic strategy, in which FLP recombinase would excise a donor molecule and I-SceI would linearise it to stimulate recombination. The full knockout technology did not work because FLP-mediated excision was not detected in the mosquito germline. However, the component tests revealed something more broadly important: I-SceI-induced breaks were repaired predominantly through homology-based pathways rather than simple end joining. We also observed inheritance distortion consistent with both gene conversion and loss of damaged gametes. These results help explain why homing-based systems can work in mosquitoes, while also highlighting why repair pathway choice and gamete viability need to be measured directly in any new drive configuration.

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Population Genetics of Native Red Mulberry at Its Northwestern Boundary Suggests Postglacial Founder Effects

Schreier, S. J.; Nepal, M. P.

2026-07-14 evolutionary biology 10.64898/2026.07.11.737963 medRxiv
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Morus rubra is native to the eastern United States, with its range extending into the Upper Midwest and southern Ontario, Canada. Its present distribution suggests that past glacial events in North America may have influenced the genetic structure of populations at the species northwestern range boundary. This study assessed genetic variation among six M. rubra populations believed to have experienced postglacial colonization using published nuclear microsatellite markers and sequences from the chloroplast trnL-trnF region. Five nuclear microsatellite markers previously developed for M. alba were successfully transferred to M. rubra, while the chloroplast trnL-trnF region provided an additional marker for evaluating chlorotype diversity. Nuclear microsatellite diversity was higher in southern unglaciated populations than in northern glaciated populations, a pattern consistent with the observed distribution of chlorotype diversity. Together, these results support ancient founder effects associated with leading-edge expansion following glacial recession and suggest that postglacial colonization contributed to the present-day genetic structure of M. rubra at its northwestern range boundary. Because M. rubra hybridizes with the naturalized invasive M. alba, reduced genetic diversity in marginal populations may increase their vulnerability to genetic swamping. The markers characterized in this study provide useful tools for population genetic research in Morus, and the findings have important implications for the conservation and management of marginal and threatened M. rubra populations in the Upper Midwest.

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Dichloroacetate improves animal survival, growth, neuromuscular activity, mitochondrial stress and physiology, and elevated lactate in C. elegans pdha-1 and dld-1 RNAi models of pyruvate dehydrogenase complex deficiency (PDCD)

Remes, C.; Mathew, N. D.; Miranda, V.; Haroon, S.; O'Hara, T.; Anderson, V. E.; Lavorato, M.; Keith, K.; Xiao, R.; Nakamaru-Ogiso, E.; Falk, M. J.

2026-07-10 cell biology 10.64898/2026.07.08.737008 medRxiv
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Pyruvate dehydrogenase complex (PDHc) deficiency (PDCD) is a primary mitochondrial disorder characterized by neurodevelopmental disability, altered intermediary metabolism and early mortality. Dichloroacetate (DCA), a pyruvate analogue, is a well-described PDHc activator that remains under clinical investigation for treatment of PDCD. Here, we studied the in vivo efficacy of a 5-point log concentration range of DCA on animal health and metabolism in C. elegans with feeding RNA interference (RNAi) expression knockdown of either PDHA-1 or DLD-1 homologues at graded degrees to model variable disease severity. These worm models recapitulate phenotypic features of PDCD observed in human patients, including reduced survival, delayed growth, locomotor impairment, and elevated lactate and/or pyruvate tissue levels. DCA treatment appeared well-tolerated, with no gross morphologic toxicity seen at doses up to 25 mM. Significantly improved health, survival, tissue lactate levels, and mitochondrial physiology were observed at 25 mM in pdha-1(RNAi) knockdown animals. DCA treatment in dld-1(RNAi) C. elegans models (undiluted, 1:20 dilution, and 1:100 dilution) showed significant therapeutic benefits on survival, neuromuscular function and metabolic phenotypes primarily in the moderate (1:20) and/or mild (1:100) dld-1(RNAi) deficiency strains, but not in full-dose dld-1(RNAi). Importantly, linear growth, neuromuscular activity, and mitochondrial physiology were significantly improved with DCA treatment even in the most severe dld-1(RNAi) undiluted model. Overall, preclinical modeling provides objective evidence of DCA therapeutic efficacy in C. elegans expression knockdown strains for two well-conserved homologues of PDHA1 and DLD that represent distinct genetic etiologies of PDHc deficiency, with demonstrated beneficial effects on survival, healthspan, tissue lactate, and mitochondrial physiology. These data further confirm that DCA's therapeutic effect correlates with PDHc disease phenotype severity in dld-1(RNAi) animals.

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PhaseWY: A pipeline for haplotype phasing, sex chromosome identification and extraction of sex-limited sequences

Ellerstrand, S. J.; Churcher, A. M. J.; Kutschera, V. E.; Hansson, B.

2026-06-22 bioinformatics 10.64898/2026.06.17.732863 medRxiv
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Sex chromosomes are central to many ecological and evolutionary processes. Evidence has accumulated that sex chromosome systems vary extensively in age, turnover and transitions, motivating renewed efforts to study the diversity of sex chromosome systems across the tree of life. However, successful genomic detection of sex chromosomes depends on several factors, including the size and divergence time, background genetic diversity, and the number of sequenced females and males. In addition, technical challenges associated with sequencing and analysing the sex-limited Y/W chromosome remain. Here, we present PhaseWY, an automated Snakemake pipeline that uses whole-genome sequencing data from multiple female and male individuals to identify sex-chromosomal regions and extract the corresponding Y/W sequences. PhaseWY (i) detects sex differences in alignment depth, (ii) applies read-based and statistical haplotype phasing, (iii) identifies sex-linked regions using haplotype clustering, and (iv) subsets autosomal, X/Z- and Y/W-linked variants for downstream analyses. We applied PhaseWY to simulated data to benchmark factors influencing sex-linkage detection and successful extraction of Y/W-linked variants. To demonstrate its practical utility, we further applied PhaseWY to the neo-sex chromosome system in Alauda larks (Alaudidae) and performed a range of downstream analyses demonstrating the scope of applications of the PhaseWY output. We conclude that PhaseWY provides an easy-to-use and reproducible tool for population-genomic analyses in non-model organisms, with particular importance for advancing our understanding of sex-chromosome evolution.

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Comparison of localGEBV and Optimal Haplotype Stacking Fitness Functions using a Novel R Package: HapSelect

Shaffer, W.; Papin, V.; Carter, Z.; Brunner, S. M.; Tong, J.; Villiers, K.; Robinson, H.; Voss-Fels, K.; Hayes, B. J.; Hickey, L.; Dinglasan, E.

2026-07-13 genetics 10.64898/2026.07.08.737160 medRxiv
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Haplotype-based breeding strategies have emerged as promising approaches to maximize long-term genetic gain by identifying complementary parental combinations while maintaining genetic diversity. However, these methods typically require phased genotypes and more intensive workflow pipelines and skillsets. We developed a novel local genomic estimated breeding value (localGEBV) fitness function with similar intent to the optimal haplotype stacking (OHS) framework fitness function and implemented both in the novel R package, HapSelect. Our aim was to evaluate whether phased haplotypes provide additional benefit over the more easily available dosage-based unphased genotypes in highly inbred crops. A subset of bread wheat nested association mapping (NAM) population comprising 444 lines genotyped with 6,054 DArT-Seq markers was analysed. Marker effects were estimated using rrBLUP, localGEBV and haplotype effects were calculated across linkage disequilibrium-defined haploblocks, and genetic algorithms (GA) were used to identify optimal sets of 30 founders using either a localGEBV derived fitness function with unphased, dosage inputs or the OHS fitness function with phased inputs. Selected parental sets were compared with conventional truncation selection (TS) through 150 generations of forward simulation. The OHS fitness function achieved a marginally greater optimized ultimate GEBV than the localGEBV fitness function during GA optimization, with only 18 of the 30 selected founders overlapped between the two methods. Despite these differences, forward simulations demonstrated nearly identical long-term genetic gain for localGEBV and OHS-selected founders, with both approaches outperforming conventional truncation selection by maintaining greater genetic diversity and delaying the genetic plateau. The minimal difference between localGEBV and OHS is likely attributable to the high homozygosity of the population, where localGEBV and haplotype effects are nearly confounded. These results demonstrate that dosage-based localGEBV provides a practical alternative to phased haplotype approaches for parent selection in inbred crops, substantially simplifying genomic workflows while maintaining long-term breeding performance. Future work should evaluate these methods in more diverse inbred populations and outbred species, where great haplotypic diversity may increase the advantage of true haplotype-based optimizations.