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Evidence for dual pathways of Tc1/mariner domestication in Drosophila.

BACKGROUND: The domestication of transposable elements is a key source of evolutionary innovation, yet the pathways by which their functional modules are repurposed by the host remain poorly understood. The Tc1/mariner superfamily is a widespread group of DNA transposons, but the prevalence and patterns of their domestication are underexplored. RESULTS: We performed a systematic genomic screen across 43 drosophilid species using stringent criteria for molecular domestication. This analysis identified five high-confidence, evolutionarily conserved genes derived from Tc1/mariner transposases. Phylogenetic and structural analyses suggest domestication via two distinct molecular pathways: co-option of the DNA-binding module and co-option of the catalytic domain. The DNA-binding module pathway includes CG4570, the previously known genes cag and toy (the latter fused with a homeodomain), and a lineage-restricted gene in the Drosophila obscura group that exhibits signatures of recent domestication. In contrast, the catalytic domain pathway is represented solely by CG14478. Structural modeling reveals that CG14478 protein preserves a canonical DDE endonuclease fold. Co-expression network analysis suggests potential cellular roles of these genes: CG14478 is linked to RNA/chromatin-related processes, CG4570 to cell cycle/chromosome functions, cag to ciliary and nuclear functions, and toy to neuronal development. CONCLUSIONS: This study establishes a stringent framework for identifying domesticated TEs, demonstrating that Tc1/mariner elements are co-opted via two distinct pathways: retention of either catalytic or DNA-binding modules. Our findings suggest that domestication is a dynamic continuum, ranging from recent, lineage-specific events to ancient, conserved genes, and underscore how genomic conflict with TEs can drive eukaryotic evolution and regulatory complexity.

Animals

Distinct types of selection and genetic architecture shape molecular variation during the domestication of vegetable crops.

Humans select vegetable crops with desirable traits via a complex evolutionary process called domestication, generating a variety of cultivars worldwide. With advances in sequencing technologies, genomic scans for "signatures of selection" are widely used to identify target loci of selection. In the early phases of domestication, humans tended to favor similar sets of phenotypes in diverse crops, resulting in "domestication syndrome" and parallel evolution in multiple species. Subsequently, adaptation to distinct environments or different consumer preferences has diversified crop cultivars. Here, we review molecular and population genetic studies on genes affecting trait evolution during this complex process. We emphasize that, depending on interactions among different types of selection (directional selection within or divergent selection between groups), the genetic architecture of the target trait (Mendelian or polygenic), and the origin of the causal variant (new mutation or standing variation), the resulting molecular patterns of variation can be highly diverse. Situations in which the typical hard selective sweep model could be applied may be limited. Therefore, it is crucial to obtain a thorough understanding of the target species' historical, environmental, and ecological contexts.

Domestication

Molecular investigation of the progenitors, origin and domestication patterns of diploid Chinese old garden roses.

BACKGROUND AND AIMS: Chinese old garden roses are major contributors to the genetic development of modern roses. The RoKSN gene is associated with continuous flowering in roses and is proposed to have originated from Chinese wild roses. However, the wild roses that are implicated in the breeding of Chinese old garden roses and the origin of the RoKSN locus remain unidentified. We collected 25 of the most renowned and classic diploid Chinese old garden roses along with all related wild roses from East Asia. These roses were analysed with the aim of identifying the wild species that contributed to the genetic composition of Chinese old garden roses. In addition, we aimed to infer the geographical origin of the RoKSN gene and to develop a schematic overview of hybrid domestication of Chinese old garden roses. METHODS: We compared the haplotypes of internal transcribed spacers (nrITS), six nuclear single-copy genes and three chloroplast genes between Chinese old garden roses and wild roses. Additionally, we assessed genetic organization using 21 expressed sequence tag-simple sequence repeats to identify potential donor species that contributed to the emergence of these cultivars. Primers were designed for RoKSN to allow comparison of the gene across the entire distribution range of Rosa sect. Chinenses. KEY RESULTS: Our findings confirmed that the majority of rose cultivars are descendants of early hybridization events. Rosa chinensis var. spontanea, R. odorata var. gigantea and R. multiflora var. cathayensis were the primary donors for the 25 cultivar roses. Chinese old garden roses were categorized into four groups. Ten cultivars were hybrids between R. chinensis var. spontanea and R. multiflora var. cathayensis, thereby forming the 'Old Blush' group. Five cultivars were hybrids between 'Old Blush' and the R. kwangtungensis species complex, thereby forming the 'Slater's crimson' group. Six cultivars were hybrids between 'Old Blush' and R. odorata var. gigantea, thereby forming the 'Tea Rose' group, and three cultivars were hybrids that evolved from more than three donors. Moreover, we observed relatively close genetic proximity among Chinese old garden roses with an identical RoKSN-copia gene that is responsible for continuous flowering, which indicates a single origin for this retrotransposon-containing allele. Additionally, we determined that the haplotypes of the RoKSN-copia gene predominantly occurred in the Sichuan Basin region. In contrast, R. chinensis cultivated in the Ya'an region showed no markers of hybridization and displayed a genetic composition that was close to that of the wild species R. chinensis var. spontanea. This cultivar may represent the earliest mutated individual that bears the RoKSN-copia gene and may have served as a bridge from wild species to continuous-flowering old rose cultivars. CONCLUSIONS: The study provides crucial evidence that elucidates the origin of cultivated roses and lays the groundwork for further analysis of the breeding history of Chinese old garden roses using genomic data.

Domestication

The evolution of plants and animals under domestication: the contribution of studies at the molecular level.

Protein molecules are essential catalysts in life processes and also form much of the substance of living material. Their three dimensional structures determine their biological function. Their biosynthesis is primarily determined by arrays of nucleic acid macromolecules (DNA and RNA), and the amino acid sequences that constitute their long spatially organized peptide-chain molecules reflect at one remove this DNA coding system, and thus record a step-by-step history of some of the viable genetic events (natural or man-controlled) that have created the organism and the breed. Amino acid sequences can be used to trace the progress of controlled breeding in two ways: by extrapolation back from living breeds, and by analysis of ancient protein material. Of the latter, bone or tendon or skin collagens and hair keratins are the most perfectly preserved as molecular structures through 20,000 years and indeed much longer. Amino acid sequences are expensive to determine (collagen has 1052 amino acid residues), and the potential of this palaeobiological information has been as yet little exploited. The first approach has, however, been more explored, in both plants and animals. Several protein systems must be studied in conjunction to reveal the phylogenetic threads in any one breed. As the three dimensional quaternary structure of protein molecules becomes more appreciated in relation to biological function, and as new techniques and procedures are developed, amino acid sequence data can become more informative in our ultimate understanding of early selective breeding.

Amino Acid Sequence

First molecular detection and partial ORF1 characterization of psittacine beak and feather disease virus (PBFDV) in domesticated parrots of Northern Vietnam.

Psittacine beak and feather disease virus (PBFDV), currently classified within the species Circovirus parrot, is an infectious agent in avian species, particularly psittacine birds. PBFDV is the causative agent of psittacine beak and feather disease (PBFD), leading to feather loss, deformed beaks and nails, immunosuppression, and high mortality. However, there is limited information on PBFDV in Vietnam, particularly in domesticated parrots. This study aims to detect and molecularly characterize PBFDV in psittacine birds in Northern Vietnam. Among the 193 psittacine birds tested by conventional PCR, 48 were PBFDV-positive, corresponding to a positivity rate of 24.87%. Based on partial ORF1 characterization, phylogenetic tree analysis of the ten PBFDV sequences showed that genotype I, which exhibits genetic diversity, is circulating in Vietnam. This study highlights the importance of genomic characterization of PBFDV in domesticated exotic psittacine birds in Vietnam. Together with the recent cases of PBFD in domestic parrots, further surveillance is needed to elucidate the host specificity, transmission, and pathophysiology of PBFDV.

Animals

Molecular shifts in limb identity underlie development of feathered feet in two domestic avian species.

Birds display remarkable diversity in the distribution and morphology of scales and feathers on their feet, yet the genetic and developmental mechanisms governing this diversity remain unknown. Domestic pigeons have striking variation in foot feathering within a single species, providing a tractable model to investigate the molecular basis of skin appendage differences. We found that feathered feet in pigeons result from a partial transformation from hindlimb to forelimb identity mediated by cis-regulatory changes in the genes encoding the hindlimb-specific transcription factor Pitx1 and forelimb-specific transcription factor Tbx5. We also found that ectopic expression of Tbx5 is associated with foot feathers in chickens, suggesting similar molecular pathways underlie phenotypic convergence between these two species. These results show how changes in expression of regional patterning genes can generate localized changes in organ fate and morphology, and provide viable molecular mechanisms for diversity in hindlimb scale and feather distribution.

Animals

Mycoplasma and Bartonella in cats from the tropical tourist Gili Islands, Indonesia.

Bartonella spp. and haemotropic Mycoplasma spp. are important vector-borne bacteria of veterinary and zoonotic relevance, yet information on their circulation in Indonesian island ecosystems remains limited. We investigated their occurrence and molecular diversity in 117 domestic and free-roaming cats from the Gili Islands, Indonesia, using full-length 16S rRNA nanopore metagenomics followed by targeted PCR, sequencing, phylogenetic analysis and multilocus sequence typing (MLST). Bartonella DNA was detected in 18/117 (15.4%) cats and haemotropic Mycoplasma DNA in 40/117 (34.2%). Sequence analysis identified Bartonella henselae as the predominant species together with Bartonella clarridgeiae. MLST of B. henselae revealed three sequence types (ST1, ST16 and ST42), with ST1, a lineage reported in both feline and human isolates, predominating. Comparison with the PubMLST database showed significant geographical differences in the distribution of ST1 and ST42, supporting regional variation in the circulation of B. henselae lineages. Haemoplasma characterization identified Candidatus Mycoplasma haemominutum, Mycoplasma haemofelis, Candidatus Mycoplasma turicensis and a Mycoplasma feliminutum-like organism, comprising ten distinct sequence variants. Haemoplasma positivity was significantly associated with age, with adults showing higher positivity than younger animals (P < 0.001), whereas Bartonella infection was not associated with age, sex or island of origin. The detection of zoonotically relevant B. henselae lineages and the genetic diversity of feline haemoplasmas provide evidence of the circulation of vector-borne bacteria among cats in this tropical island ecosystem. These findings provide the first molecular epidemiological baseline for this region and contribute to understanding the circulation and genetic diversity of feline vector-borne pathogens in Southeast Asia.

Animals

Cucurbitacins in Plant-Insect Interactions: Biosynthesis, Regulation, Ecological Functions, and Prospects for Crop Protection.

Cucurbitacins are highly oxygenated tetracyclic triterpenoids characterized by intense bitterness, substantial structural diversity, and important consequences for plant-herbivore interactions. Although best known from Cucurbitaceae, cucurbitacins and related cucurbitane-type metabolites also occur in phylogenetically distant herbaceous and woody plants. Genetic and biochemical studies have validated several core biosynthetic steps, including cucurbitadienol formation by oxidosqualene cyclases and subsequent modification by cytochrome P450 monooxygenases, acyltransferases, and glycosyltransferases. Tissue-preferential basic helix-loop-helix transcription factors constitute the best-characterized regulatory layer, whereas the evidence supporting accessory regulators, transporters, and environmental responses varies from functional validation to transcriptomic or genomic prediction. From the plant perspective, cucurbitacins deter feeding or impair performance in many generalist and non-adapted herbivores. By contrast, their use as host-recognition cues and feeding stimulants by specialist diabroticite beetles reflects evolved herbivore adaptations involving perception, tolerance, metabolism, or sequestration rather than a second defensive function of the plant trait. Herbivore-induced cucurbitacin accumulation has been demonstrated in particular systems, although its regulatory mechanisms and ecological generality remain unresolved. Unlike previous reviews centered primarily on cucurbitacin chemistry, pharmacological activity, or individual biosynthetic pathways, this review integrates evidence-graded pathway reconstruction and molecular regulation with taxonomic distribution, insect adaptation, domestication, and agroecological consequences. Mechanistically, this review traces how scaffold formation, oxidative tailoring, conjugation, tissue-specific regulation, and transport give rise to contrasting ecological outcomes through herbivore-specific perception, tolerance, metabolism, and sequestration. We conclude that uniformly increasing or eliminating cucurbitacins is unlikely to provide broadly effective crop resistance because either direction may favor a different herbivore group. Future priorities include functional validation of candidate genes, spatially resolved metabolite analysis, comparative investigation of non-cucurbit lineages, and field evaluation involving generalist and specialist herbivores, crop quality, and non-target organisms. These advances will support context-specific fruit-quality improvement, behavioral pest control, and integrated pest management strategies rather than cucurbitacin manipulation as a stand-alone resistance approach.

agroecology

Detection of Rickettsia species with seroreactivity to Rickettsia tillamookensis and Rickettsia rickettsii subsp. californica in domestic dogs in Northern California.

Rickettsia species phylotype G022 (G022) and Rickettsia tillamookensis both maintain a low infection prevalence in Ixodes pacificus ticks and share a close phylogenetic history with pathogenic Rickettsia species. The transmission mechanisms and pathogenic potential of I. pacificus-borne Rickettsia are poorly understood. The low prevalence of G022 and R. tillamookensis suggests that vertebrate species are utilized for maintenance, though identification of vertebrate amplifier and reservoir hosts utilized by Rickettsia is limited. To evaluate the molecular occurrence of G022 and R. tillamookensis and the sentinel utility of domestic dogs, a molecular survey was conducted. Buffy coat and blood plasma samples from 175 domestic dogs collected from Humboldt and Sonoma counties in northern California were screened for rickettsial DNA and anti-rickettsial antibodies, respectively. Dogs were screened for antibodies against Rickettsia spp. and tested for seroreactivity against R. tillamookensis, Rickettsia rickettsii subsp. californica, and Rickettsia rhipicephali. Because G022 has not yet been isolated, this Rickettsia species was omitted from the serological survey. Of the 175 dogs tested, three (1.71%; 95% CI: 0.58%-4.90%) were seropositive for Rickettsia spp. by indirect immunofluorescence antibody assay (IFA); two dogs (1.14%; 95% CI: 0.31%-4.10%) demonstrated seroreactivity by enzyme-linked immunosorbent assay (ELISA), suggesting previous exposure to Rickettsia spp. Among dogs from Sonoma County, 2.88% (3/104; 95% CI: 1.0%-8.14%) of plasma samples were seropositive for Rickettsia spp. by IFA, and 1.92% (2/104; 95% CI: 0.53%-6.74%) demonstrated seroreactivity by ELISA, while all the dogs from Humboldt County were seronegative for both methods. Although the ELISA results were not considered species-specific, two plasma samples demonstrated the greatest seroreactivity against R. tillamookensis and R. rickettsii subsp. californica, respectively, suggesting previous exposure to Rickettsia spp. with epitope similarity to R. tillamookensis and R. rickettsii subsp. californica, respectively. No DNA was detected for G022 or R. tillamookensis by quantitative real-time PCR, with a limit of detection of approximately 3.6 target copies per reaction for G022 and 1 genomic copy per 2&#xa0;&#x3bc;l of template DNA per reaction for R. tillamookensis.

Animals

From wild to domestic: Single-cell transcriptomic perspectives on hippocampal regulation and evolution.

How domestication shapes brain evolution remains an open question. In this study, we integrated single-nucleus RNA sequencing (snRNA-seq), population genomics, and machine learning to investigate the hippocampal evolution under domestication. Across-species comparisons revealed that hippocampal cell type profiles are largely conserved across vertebrate species, while supporting the presence of adult hippocampal neurogenesis in birds. We further found that domestication and selective breeding likely influence the cellular composition and molecular regulation of the hippocampus. Our findings provide cellular evidence supporting the hypothesis that domestication affects adult hippocampal neurogenesis. Additionally, we showed that genes associated with neural progenitor cells (NPC) states and cell-marker programs are enriched for signatures of selection. Many of these genes function as regulators of neurogenesis and pathways mediating stress and fear reduction. Specifically, we identified selection at the FKBP5 promoter that may influence its expression in the NPC lineage, potentially contributing to stress-response regulation during domestication. Collectively, these results suggest that domestication is associated with hippocampal remodeling as part of an adaptive response to human-managed environments. This study provides a cellular and genetic perspective on how domestication reshapes the brain and offers a basis for further investigation into the mechanisms of neural evolution within the context of microevolution.

Animals

Evolution of maize recombination landscape during domestication.

Despite the plethora of knowledge about the benefits of meiotic recombination and numerous theoretical studies examining how recombination rates evolve, there is a general lack of empirical support and consensus across species. To fill this knowledge gap, we characterized the evolution of recombination landscape in maize during its domestication from teosinte and related the observed changes to established theoretical frameworks. Through examining recombination in experimental populations of maize and teosinte and the population genomics approach of identifying historical recombination events using ancestral recombination graph inference to generate saturated maize and teosinte recombination maps, we found that during domestication, maize experienced a 12% increase in its genome-wide recombination rate. Furthermore, maize evolved higher recombination rates on the long arms of chromosomes in regions closer to centromeres, where recombination is generally very low. The repatterning of crossover events came from changes in global crossover positioning rather than alterations in cis-acting chromatin factors. Consequently, we found evidence of selection acting on trans-acting recombination modifiers affecting crossover interference and controlling the interference-dependent class I crossover pathway. We show that CO repatterning was likely beneficial for maize fitness, as significant recombination rate increases were predominantly in gene-rich regions, which harbor domestication-related variation. This work suggests genomic and mechanistic processes leading to the evolution of meiotic recombination landscape in response to directional selection pressure and provides evidence for the evolutionary advantage of recombination.

Zea mays

Selection of GhTT2-A07 promoter enhances fiber quality in improved cotton varieties.

Modern cultivated cotton fibers are predominantly white with enhanced quality compared to their wild ancestors. However, the molecular mechanisms and evolutionary drivers linking fiber color to quality remain least focused. In this study, we identified FQC1 (Fiber Quality and Color 1), a major quantitative trait locus (QTL) on chromosome A07 that concurrently regulates both fiber quality and pigmentation. Through map-based cloning, we revealed that Gossypium hirsutum TRANSPARENT TESTA2-A07 (GhTT2-A07), an R2R3-MYB transcription factor, resides within this locus. GhTT2-A07 modulates fiber development by directly activating genes in the general phenylpropanoid pathway, thereby promoting the metabolic flux toward downstream secondary metabolites. Variations in the GhTT2-A07 promoter led to its reduced expression in modern white cotton cultivars. This down-regulation suppresses the accumulation of S/G/H-type lignin monomers and proanthocyanidins, resulting in altered secondary cell wall composition and ultimately enhancing the quality of mature white fibers. Population genetic analyses further indicate that the white-fiber allele GhTT2-A07W has been fixed in modern breeding genotypes, underscoring the impact of artificial selection during cotton domestication. Overall, our study elucidates the biochemical and molecular mechanisms underlying fiber quality and pigmentation in cotton, clarifies the selection criteria for high-quality white fibers in modern cultivars, and provides a theoretical basis for future targeted genetic improvement of cotton fibers.

Alleles

Domestication as gene-culture coevolution.

Human preferences can shape the genetic evolution of other species via conservation practices, public health actions, and domestication. While the dynamics of domestication have been explored in depth through empirical and theoretical analyses, few studies have analyzed models for the coevolution of human cultural preferences with the genetics of a domesticate population. Humans shape the fitness landscape of domesticate populations both intentionally and unconsciously, by selecting for desirable traits and modifying environments; in turn, changes in domesticate phenotypes can affect the cultural preferences in the domesticator population. We present a model for the dynamics of domestication which includes interactions between genetic evolution, cultural transmission, and selective pressures. The model includes forms of selection due to culturally transmitted domesticator preferences that can affect the dynamics of domesticate genetic variants, which then affect the dynamics of domesticators. Equilibria with simultaneous genetic and cultural polymorphisms may exist, and may occur under apparent heterozygote disadvantage in the domesticate. Stable quasiperiodic cycles in both domesticates and domesticators are also possible.

Humans

Near-complete reference genome assembly of Hoya carnosa.

Hoya R. Br. is the largest genus in the tribe Marsdenieae (Apocynaceae), comprising 350-450 species. Hoya species are popular in horticulture for their distinctive floral traits and fragrances, primarily sourced from domestication and mutation breeding. However, the lack of molecular analysis for floral morphological traits has limited their cultivation and application. In this study, we assembled a near-complete reference genome for H. carnosa, the model species of the genus, using PacBio HiFi reads and Hi-C method. The genome size was approximately 465.7&#x2009;Mb with a contig N50 of 39.3&#x2009;Mb. 99.7% of the sequences were anchored to 11 pseudochromosomes, and the assembly achieved a BUSCO score of 98.5%. We predicted 24,309 protein-coding genes, of which 90.2% (21,927) were functionally annotated. This high-quality genome provides a valuable reference for the research of evolution, conservation and molecular breeding in Hoya.

Genome, Plant

Domesticated Argania spinosa in Eastern Morocco: HPLC-DAD/GC-MS Chemical Profiling, Antioxidant and Antidiabetic Activities, and Network Pharmacology-Guided Molecular Docking.

The argan tree (Argania spinosa) is an endemic Moroccan species known for its primary product, argan oil, which possesses exceptional nutritional and medicinal properties. The current study aimed to evaluate and compare the antidiabetic and antioxidant activities of argan oil obtained from the introduced and native argan tree in eastern Morocco, to analyze its chemical composition using HPLC-DAD and GC-MS, and to investigate the molecular mechanisms behind the obtained pharmacological activities through an in silico pharmacological networking and molecular docking study. The results revealed that argan oil from all three regions of Morocco (Oujda, Agadir, and Chouihya) is rich in oleic and linoleic acids as major constituents, along with the presence of significant tocopherols. Regarding the antioxidant assays, including DPPH radical scavenging and iron-reducing power tests, argan oil from Oujda exhibited the highest activity, with the lowest IC50 values of 15.25 &#xb1; 0.022 mg/mL and 28.5 &#xb1; 1.7 mg/mL, respectively. Concerning the antidiabetic activity, we found that oil from Chaouihya showed the strongest &#x3b1;-amylase inhibition, while Oujda oil had the highest antiglycation activity, indicating that even introduced argan trees retain potent bioactivity. The results of the in silico investigation suggested that tocopherols may contribute to the antioxidant and antidiabetic potential of argan oil, showing predicted antioxidant activity (Pa = 0.843-0.967) and favorable binding affinities toward iNOS (&#x394;G = -9.3 kcal mol-1) and &#x3b1;-glucosidase (&#x394;G = -8.2 kcal mol-1). The identified fatty acids also showed predicted insulin-promoting activity (Pa = 0.59-0.75) and moderate enzyme-binding potential. Pharmacological network analysis identified 51 shared genes associated with antioxidant, antidiabetic, and argan-related targets, with enrichment of the AGE-RAGE signaling pathway. These computational findings provide possible molecular associations that may help explain the observed biological activities, although they remain predictive and require experimental validation. Overall, the in silico analysis suggests that tocopherols could be among the contributors to the multi-target profile of Argania spinosa oil, while fatty acids may provide complementary effects related to glycemic regulation.

Sapotaceae

Molecular breeding of tomato: Advances and challenges.

The modern cultivated tomato (Solanum lycopersicum) was domesticated from Solanum pimpinellifolium native to the Andes Mountains of South America through a "two-step domestication" process. It was introduced to Europe in the 16th century and later widely cultivated worldwide. Since the late 19th century, breeders, guided by modern genetics, breeding science, and statistical theory, have improved tomatoes into an important fruit and vegetable crop that serves both fresh consumption and processing needs, satisfying diverse consumer demands. Over the past three decades, advancements in modern crop molecular breeding technologies, represented by molecular marker technology, genome sequencing, and genome editing, have significantly transformed tomato breeding paradigms. This article reviews the research progress in the field of tomato molecular breeding, encompassing genome sequencing of germplasm resources, the identification of functional genes for agronomic traits, and the development of key molecular breeding technologies. Based on these advancements, we also discuss the major challenges and perspectives in this field.

Solanum lycopersicum

Animal breeding and disease.

Single-locus disorders in domesticated animals were among the first Mendelian traits to be documented after the rediscovery of Mendelism, and to be included in early linkage maps. The use of linkage maps and (increasingly) comparative genomics has been central to the identification of the causative gene for single-locus disorders of considerable practical importance. The 'score-card' in domestic animals is now more than 100 disorders for which the molecular lesion has been identified and hence for which a DNA test is available. Because of the limited lifespan of any such test, a cost-effective and hence popular means of protecting the intellectual property inherent in a DNA test is not to publish the discovery. While understandable, this practice creates a disconcerting precedent. For multifactorial disorders that are scored on an all-or-none basis or into many classes, the effectiveness of control schemes could be greatly enhanced by selection on estimated breeding values for liability. Genetic variation for resistance to pathogens and parasites is ubiquitous. Selection for resistance can therefore be successful. Because of the technical and welfare challenges inherent in the requirement to expose animals to pathogens or parasites in order to be able to select for resistance, there is a very active search for DNA markers for resistance. The first practical fruits of this research were seen in 2002, with the launch of a national scrapie control programme in the UK.

Animal Diseases

Graph-based pan-genome reveals structural and functional diversity across oil palm domestication gradients.

BACKGROUND: Oil palm (Elaeis guineensis Jacq.), the world's most land-efficient oil crop, underpins global vegetable oil supply yet faces mounting constraints from limited expansion, climate stress, and disease pressure. These challenges highlight the urgent need for genomic resources that capture species-wide diversity to support sustainable improvement. While recent reference assemblies have advanced trait discovery, single linear genomes fail to represent the full spectrum of structural and gene-content variation, limiting resolution of agronomic alleles. RESULTS: Here, we constructed a graph-based pan-genome from 30 diverse oil palm assemblies representing wild, semi-domesticated, and commercial accessions. We characterized structural variants, gene presence-absence variation, and copy-number gains, with focusing on functional stratification and resistance gene dynamics. The graph-based pan-genome revealed extensive structural and gene-content variation, including a large conserved core, complemented by shell and unique fractions enriched or biased toward regulatory, stress-responsive, and defense-related functions. Structural variation and duplication-derived copy-number gains contributed substantially to gene-content diversity, with semi-domesticated accessions exhibiting the greatest variability. Resistance gene repertoires showed contrasting patterns: receptor-like kinases remained comparatively stable, whereas the CNL subclass of NLR genes contributed disproportionately to shell-genome variation and duplication-associated turnover. CONCLUSIONS: This graph-based pan-genome provides a curated multi-assembly reference and comparative framework for oil palm genomics. By capturing structural variants, gene-content variations, copy-number gains, and resistance gene dynamics across domestication gradients, it establishes a foundation for future pan-GWAS analysis, functional genomics, and molecular breeding strategies aimed at improving resilience and productivity in this globally important crop.

Arecaceae