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Babesia ovis is a unicellular parasite of sheep and goats transmitted by the tick Rhipicephalus bursa. B. ovis infection is widespread and can be lethal, and therefore there is need for a deeper understanding of its biology and pathogenesis. There is currently a single genome available for a clinical isolate of B. ovis, and no laboratory strains have been sequenced so far. In this study we have sequenced and assembled the genome of the Israeli laboratory strain of B. ovis using highly accurate long-read sequencing (PacBio HiFi). The resulting assembly has high contiguity, with the four largest contigs comprising 96% of the assembly and representing putative near-complete chromosomes. Annotation identified 3,549 genes, of which 3,046 (85.6%) could be functionally annotated. BUSCO analysis on the annotated genes revealed 95.5%, 98.8% and 100% completeness of the Aconoidasida, Apicomplexa, and Alveolata lineages, respectively. Comparative analysis with other annotated piroplasmida genomes reveals the vast majority of predicted genes clustered in orthogroups. The availability of a high-quality genome assembly for a tractable laboratory strain could prove impactful in unlocking more basic and applied research avenues to be pursued for this important parasite system.

Population genomics can reveal trends and drivers of biodiversity loss, but it is still unclear how best to use measures of genome variation to understand population vulnerability in insects. Here we study genome variation in three species of Anthophora bees that show contrasting population trends in northern Europe. Two species, Anthophora plagiata and Anthophora retusa , have experienced declines and recoveries of different magnitudes in the last 50 years, whereas a third species, Anthophora quadrimaculata , has relative population stability. We generate highly contiguous genome assemblies and use them to study genome variation in 136 samples of these species collected throughout Sweden. We find exceedingly low genetic variation in A. plagiata , which has experienced a severe recent bottleneck, but high genetic variation in A. retusa , despite a similar recent population trajectory. Fragmented populations of the threatened species A. plagiata appear isolated from each other, but in A. retusa, there is a lack of deep population structure among geographically separated subpopulations. We infer population size in the distant past using MSMC2 and recent past using GONE. These methods are remarkably concordant and indicate ancient fluctuations in population size dating back to the Pleistocene, with moderate expansions in the past century in all three species. These results are comparable to some other studies of endangered insects, which have experienced population declines that predate the modern era. We detect long blocks of identity-by-state in A. plagiata , indicative of severe recent inbreeding. Translocations between isolated populations of this species could have a positive effect on their resilience.

Xylanolytic enzyme systems in ascomycetous yeasts remain underexplored, despite the presence of yeasts in various xylan-rich ecological niches. In this study, we investigated the secreted xylanolytic machineries of three Blastobotrys species—B. mokoenaii, B. illinoisensis, and B. malaysiensis—by integrating genome annotation, bioinformatics, and secretome analyses of cultures grown on beechwood glucuronoxylan. Our findings demonstrate that these yeasts effectively hydrolyze xylan through the secretion of xylanases from the glycoside hydrolase (GH) family 11, which play a central role in cleaving the xylan backbone. Additionally, the yeasts produce a diverse array of other CAZymes, including members of GH families 3, 5, and 67, with putative roles in xylan degradation. We also report on the heterologous expression and functional characterization of the GH30_7 xylanase BmXyn30A from B. mokoenaii, which exhibits both glucuronoxylanase and xylobiohydrolase activities. We demonstrate additive effects between GH family 30 BmXyn30A and GH family 11 BmXyn11A during the hydrolysis of beechwood glucuronoxylan, where the enzymes exhibit complementary roles that enhance the deconstruction of this complex hemicellulose substrate. These findings broaden our understanding of the xylanolytic systems in yeasts and underscore the potential of Blastobotrys species as cell factories and natural xylanase producers. The enzymes they produce hold promise for biorefining applications, enabling efficient utilization of renewable xylan-rich plant biomass resources.

The clouded apollo (Parnassius mnemosyne) is a palearctic butterfly distributed over a large part of western Eurasia, but population declines and fragmentation have been observed in many parts of the range. The development of genomic tools can help to shed light on the genetic consequences of the decline and to make informed decisions about direct conservation actions. Here, we present a high-contiguity, chromosome-level genome assembly of a female clouded apollo butterfly and provide detailed annotations of genes and transposable elements. We find that the large genome (1.5 Gb) of the clouded apollo is extraordinarily repeat rich (73%). Despite that, the combination of sequencing techniques allowed us to assemble all chromosomes (n_c = 29) to a high degree of completeness. The annotation resulted in a relatively high number of protein-coding genes (22,854) compared with other Lepidoptera, of which a large proportion (21,635) could be assigned functions based on homology with other species. A comparative analysis indicates that overall genome structure has been largely conserved, both within the genus and compared with the ancestral lepidopteran karyotype. The high-quality genome assembly and detailed annotation presented here will constitute an important tool for forthcoming efforts aimed at understanding the genetic consequences of fragmentation and decline, as well as for assessments of genetic diversity, population structure, inbreeding, and genetic load in the clouded apollo butterfly.

A genomic database of all Earth's eukaryotic species could contribute to many scientific discoveries; however, only a tiny fraction of species have genomic information available. In 2018, scientists across the world united under the Earth BioGenome Project (EBP), aiming to produce a database of high-quality reference genomes containing all ∼1.5 million recognized eukaryotic species. As the European node of the EBP, the European Reference Genome Atlas (ERGA) sought to implement a new decentralised, equitable and inclusive model for producing reference genomes. For this, ERGA launched a Pilot Project establishing the first distributed reference genome production infrastructure and testing it on 98 eukaryotic species from 33 European countries. Here we outline the infrastructure and explore its effectiveness for scaling high-quality reference genome production, whilst considering equity and inclusion. The outcomes and lessons learned provide a solid foundation for ERGA while offering key learnings to other transnational, national genomic resource projects and the EBP.

The red palm weevil (RPW), Rhynchophorus ferrugineus (Coleoptera: Curculionidae), is the most devastating pest of palm trees worldwide. Mitigation of the economic and biodiversity impact it causes is an international priority that could be greatly aided by a better understanding of its biology and genetics. Despite its relevance, the biology of the RPW remains poorly understood, and research on management strategies often focuses on outdated empirical methods that produce sub-optimal results. With the development of omics approaches in genetic research, new avenues for pest control are becoming increasingly feasible. For example, genetic engineering approaches become available once a species's target genes are well characterized in terms of their sequence, but also population variability, epistatic interactions, and more. In the last few years alone, there have been major advances in omics studies of the RPW. Multiple draft genomes are currently available, along with short and long-read transcriptomes, and metagenomes, which have facilitated the identification of genes of interest to the RPW scientific community. This review describes omics approaches previously applied to RPW research, highlights findings that could be impactful for pest management, and emphasizes future opportunities and challenges in this area of research.

Animal cell lines often undergo extreme genome restructuring events, including polyploidy and segmental aneuploidy that can impede de novo whole-genome assembly (WGA). In some species like Drosophila, cell lines also exhibit massive proliferation of transposable elements (TEs). To better understand the role of transposition during animal cell culture, we sequenced the genome of the tetraploid Drosophila S2R+ cell line using long-read and linked-read technologies. WGAs for S2R+ were highly fragmented and generated variable estimates of TE content across sequencing and assembly technologies. We therefore developed a novel WGA-independent bioinformatics method called TELR that identifies, locally assembles, and estimates allele frequency of TEs from long-read sequence data (https://github.com/bergmanlab/telr). Application of TELR to a ∼130x PacBio dataset for S2R+ revealed many haplotype-specific TE insertions that arose by transposition after initial cell line establishment and subsequent tetraploidization. Local assemblies from TELR also allowed phylogenetic analysis of paralogous TEs, which revealed that proliferation of TE families in vitro can be driven by single or multiple source lineages. Our work provides a model for the analysis of TEs in complex heterozygous or polyploid genomes that are recalcitrant to WGA and yields new insights into the mechanisms of genome evolution in animal cell culture.

Cultured cells are widely used in molecular biology despite poor understanding of how cell line genomes change in vitro over time. Previous work has shown that Drosophila cultured cells have a higher transposable element content than whole flies, but whether this increase in transposable element content resulted from an initial burst of transposition during cell line establishment or ongoing transposition in cell culture remains unclear. Here, we sequenced the genomes of 25 sublines of Drosophila S2 cells and show that transposable element insertions provide abundant markers for the phylogenetic reconstruction of diverse sublines in a model animal cell culture system. DNA copy number evolution across S2 sublines revealed dramatically different patterns of genome organization that support the overall evolutionary history reconstructed using transposable element insertions. Analysis of transposable element insertion site occupancy and ancestral states support a model of ongoing transposition dominated by episodic activity of a small number of retrotransposon families. Our work demonstrates that substantial genome evolution occurs during long-term Drosophila cell culture, which may impact the reproducibility of experiments that do not control for subline identity.

The 15,619 bp mitochondrial genome of Jebusaea hammerschmidtii was assembled from short reads, annotated, and compared to the genomes of other longhorn beetles (Cerambycidae). Gene content was typical of animal mitochondrial genomes and contained 13 protein-coding, 22 tRNA, and 2 rRNA genes. Gene organization was identical to that of other longhorn beetles. Phylogenetic analysis placed J. hammerschmidtii within the subfamily Cerambycinae, and strongly supported the monophyly of the Cerambycinae, Lamiinae, and Prioninae subfamilies.