Biology subjects

Chan, Y. F.

Publications and source records attributed to Chan, Y. F..

At least 19 recordsLinked to original sources

bioRxiv2026

Experimental evolution unveils a role for structural variants and sex-specificity in the genetic architecture of lifespan

Insights into the genetic basis of lifespan evolution can link evolutionary theory with an understanding of health, disease and adaptation. We leverage the power of >200 generations of experimental evolution in a seed beetle to unveil the genomic architecture of lifespan evolution. Replicated populations evolved under regimes favoring either a short or long life, resulting in a near doubling of lifespan. Whole genome re-sequencing revealed that short- and long-lived lines were strongly differentiated (global FST = 0.41) and more than 700 genes showed consistent signs of divergent selection. Remarkably, short- and long-lived lines were consistently divergent in a large number of regions harboring copy-number variants (CNVs), involving >600 genes. The evolution of a long life involved many distinct biological processes, such as DNA fidelity, mitotic integrity, reproduction, metabolism, immunity and stress response. A pedigree-based genome scan for quantitative trait loci (QTLs) uncovered several QTLs with large effects on lifespan, but the genetic basis of a long life was dominated by a very large number of regions with medium and small effects. The genome-wide spatial association with QTL effects was, if anything, stronger for CNVs than for sequence variants. The genetic effects of QTLs on lifespan were positively correlated overall between the sexes, but four regions showed pronounced sex-differences. Our results show that structural variants play a significant role in the evolution of an extended lifespan and the highly polygenic genomic architecture is to some extent sex-specific, consistent with differences in physiology and life history tradeoffs between the sexes.

evolutionary biology↗

bioRxiv2026

BLink-seq delivers population-scale haplotypes without long reads: a scalable framework for non-model genomics

Information about segregating haplotypes and structural variation (SV) can be extremely rich for a variety of applications in population genomics but remains largely inaccessible for many non-model species. Of the available methods, linked-read sequencing is especially promising for its low cost and scalability, but its adoption remains limited. One existing linked-read method is Haplotagging, which barcodes sequencing reads to reconstruct long molecules that encode haplotype information, with the potential to generate phased whole-genome data and detect structural variants. In this study, we present BLink-seq, a novel Haplotagging method that is compatible with standard short-read next-generation sequencing platforms, is locally reproducible with low-cost reagents, and is scalable for high-throughput sample processing. We optimized library preparation parameters, explored their relationship to linked-read library metrics, and validated phasing performance and structural variant detection in two evolutionary extremes: an experimental Drosophila melanogaster cross of inbred lines carrying known inversions, and four Atlantic silverside (Menidia menidia) parent-offspring trios sourced from highly outbred, wild-caught populations. We then applied our protocol to a cohort of 376 silversides to demonstrate its scalability and potential for SV detection and genotype imputation. Using BLink-seq, we generated chromosome-scale phased blocks and identified known inversions in both validation datasets. We discovered previously uncharacterized structural complexity within a known adaptive inversion on silverside chromosome 11, demonstrating that linked-read data can refine our understanding of SV architecture beyond what short reads alone can resolve. Finally, we provide a user guide for researchers interested in using BLink-seq.

genomics↗

bioRxiv2026

Inbreeding depression is greater in benign than in stressful environments

The potential for environmental change to compound the detrimental effects of inbreeding depression in small and isolated populations is a significant concern in conservation biology. Previous evidence syntheses suggested that environmental stress exacerbates inbreeding depression, but were based on limited data. Here, we comprehensively test the relationship between inbreeding depression and environmental stress in natural populations using Bayesian mixed-effects meta-analysis on a large, high-quality data set of 2127 inbreeding depression effect sizes from animals and plants. Our results show that inbreeding depression is significantly higher in benign than in stressful environments. Analyses of both inbreeding depression and stress-induced changes in genetic load supported a unimodal (humped) relationship between the costs of inbreeding and stress intensity, with a peak at intermediate stress. At the highest levels of stress there was, on average, a significantly greater inbreeding load in benign than in stressful environments. We suggest that the lower cost of inbreeding associated with extreme stress results from constraints on the expression of inbreeding depression as fitness and phenotypes decline towards zero. Our findings help to resolve long-standing uncertainty around how inbreeding and environmental change interact, revealing that inbreeding responses vary non-linearly with environmental stress intensity, but showing that stress does not generally amplify inbreeding depression. As such, they will inform both the management of populations of conservation concern and predictions of species responses to global environmental change.

evolutionary biology↗

bioRxiv2026

Independent major-effect loci and limited trait associations characterise warning colour variation across sexes and life stages in the wood tiger moth (Arctia plantaginis)

Variation in warning colouration is common, despite strong positive frequency-dependent selection favouring the most common morph, and may arise from spatially or temporally variable selection or associations with other traits. We investigated the maintenance of warning colour variation in the wood tiger moth, Arctia plantaginis, which shows sexual dimorphism in colouration: two distinct male morphs controlled by a single locus, and continuous variation in female hindwing colour and larval warning signal size. Using whole-genome sequencing of 657 individuals from a laboratory stock derived from a wild polymorphic population, we examined the genetic basis of multiple life-history traits, chemical defence, pheromones, and male activity. We specifically tested for associations with male colour and aimed to identify the genetic basis of female and larval colour variation. We detected separate major-effect loci for female colour and larval signal size, which were different from the male colour locus. Hindwing melanism was the only trait associated with male colour, mapping to a nearby major-effect locus and showing a link to reduced activity at higher temperatures. Female colour was phenotypically correlated with pheromone amount. However, apart from melanism, none of the other traits measured showed an association with any of the loci controlling warning colours and we found no evidence that male colour is part of a supergene or complex co-adapted phenotype. Instead, our results indicate largely independent genetic architectures for warning colours suggesting that variable selection rather than genetic associations may contribute to the maintenance of colour polymorphisms in this species.

evolutionary biology↗

bioRxiv2026

Haplotype tagging sheds light on speciation between two divergent cryptic species of the brown algae Ectocarpus

Understanding how genome-wide divergence translates to barriers to gene flow is a central question in speciation research, particularly in marine environments where interconnected habitats frequently accommodate cryptic diversity. Using linked-read whole-genome data from the brown alga Ectocarpus, we investigated genome-wide reproductive isolation between two cryptic brown algal species E. siliculosus and E. crouaniorum across replicated hybrid zones in Europe and Chile. We first uncover deep genetic structure within E. crouaniorum, revealing a more intricate species complex than previously recognized. Despite this complexity, we found parallel patterns of asymmetric introgression that emerged independently in Europe and Chile, where we detected both, F1 and low-level introgressed individuals. However, the specific lineage pairs involved in hybridization depended on local demographic history. Demographic modeling further indicated that reproductive isolation strengthens gradually with divergence time and differs markedly between geographic regions, with ongoing asymmetric gene flow even between lineage pairs where hybrids were not detected in the field. In all cases, the genomic landscape of hybridization is consistent with a polygenic, genome-wide barrier to gene flow rather than a few large-effect regions. Our results show that cryptic speciation in brown algae is driven by repeatable, regionally parallel architectures of genome-wide reproductive isolation which is shaped by ecological and demographic context.

evolutionary biology↗

bioRxiv2026

G-quadruplexes regulate chromatin accessibility and gene expression in Bloom Syndrome

Bloom Syndrome (BS) is a recessive genetic disorder characterized by hyper-recombination and genome instability. It is caused by mutations in BLM, which encodes a conserved RecQ helicase that unwinds various aberrant DNA structures. One such structure is DNA G-quadruplexes (G4s), which have versatile regulatory potential in chromatin organization and gene expression. However, whether G4 profiles are altered in BS and how G4s contribute to disease-associated molecular changes remain unclear. Here, we profiled chromatin accessibility and gene expression using ATAC-seq and RNA-seq and mapped endogenous G4 by ChIP-seq in wild type (WT) and BS cell lines. We observed that in BS cell lines, differential G4 formation positively correlated with both differential chromatin accessibility and gene expression. To test the direct involvement of G4s in the molecular phenotypes in BS, we applied pyridostatin, a G4-stabilizing molecule, in WT cells and showed that G4 stabilization partially recapitulated BS-associated molecular phenotypes. Additionally, we found that regions with increased chromatin accessibility in BS individuals in a family were also enriched for G4-forming sequences. Together, our data substantiate a regulatory role for G4s in Bloom syndrome and support a molecular model in which unresolved G4s in BLM- /- cells enhance chromatin accessibility, thereby promoting gene expression. These findings reveal an expanded regulatory function of BLM mediated through G4 structures and previously underappreciated role of G4s in the molecular etiology of BS.

genomics↗

bioRxiv2025

Rapid and repeated evolution of myosin copy number in threespine stickleback

Copy number variants at genomic loci evolve at a high rate, are linked to many different diseases, and play a role in adaptive evolution in humans and other organisms. Here we show that stickleback fish from freshwater environments have rapidly and repeatedly evolved an expanded number of copies of a gene family involved in muscle development, Myosin Heavy Chain 3 Cluster C (MYH3C), compared to marine populations. Differences in copy number between marine and freshwater fish are maintained even in the presence of gene flow, suggesting that MYH3C changes represent adaptive divergence between ecotypes. Copy number expansion occurs by tandem duplication of MYH3C coding and regulatory regions on the stickleback sex chromosome. We identify a muscle regulatory enhancer within the expanded MYH3C region and show that elevated copy number is associated with developmental and tissue-specific increases in corresponding mRNA expression levels in skeletal muscle. Common MYH3C clusters include 3-, 4-, 5-, and 6-copy variants that likely evolved through a combination of microhomology-mediated break repair and non-allelic homologous recombination. Our results provide a new example of copy number changes in a wild species and identify CNVs as potential "hotspots" of repeated adaptive evolution.

evolutionary biology↗

bioRxiv2025

The collision of two genomes threatens global food security

Human activity alters selection pressures and redistributes biodiversity, creating opportunities for hybridization when dilerent species come into secondary contact. It is now well-established that ancient hybridization plays an important role in adaptive radiation 1, but its role in recent anthropogenic adaptation remains unclear. We investigated this in a study of hybridizing native and invasive Helicoverpa moths in Brazil, which are among the most economically damaging crop pests globally. Native H. zea has recently evolved Bt resistance and is better adapted to maize as a host plant, while invasive H. armigera is resistant to pyrethroid pesticides and is better adapted to soybean. Using a decade-long time series of 975 genomes from both species, we demonstrate rapid, bidirectional adaptive introgression of structural variants that cause resistance to two distinct pesticides. In one direction, a pyrethroid resistance gene from H. armigera (CYP337B3) is now almost fixed in native H. zea. In the other direction, ~30% of recently-sampled invasive H. armigera carry a H. zea-derived trypsin repeat cluster. Using controlled crosses, we show that this trypsin repeat cluster confers resistance to Bt (Cry1Ac) soy in the H. armigera genomic background. Thus, hybridization has combined H. armigera adaptation to soy with H. zea Cry1Ac resistance to facilitate exploitation of Brazilian Bt soy monoculture -- a vast anthropogenic habitat exceeding the area of Germany. Our results show that the combinatorial mechanisms that produce biodiversity can also drive rapid anthropogenic adaptation on ecological timescales, with consequences for global food security.

evolutionary biology↗

bioRxiv2025

Genealogical analysis of replicate flower colour hybrid zones in Antirrhinum

A major goal of speciation research is identifying loci that underpin barriers to gene flow. Population genomics takes a bottom-up approach, scanning the genome for molecular signatures of processes that drive or maintain divergence. However, interpreting the genomic landscape of speciation is complicated, because genome scans conflate multiple processes, most of which are not informative about gene flow. However, studying replicated population contrasts, including multiple incidences of secondary contact, can strengthen inferences. In this paper, we use linked-read sequencing (haplotagging), FST scans, and genealogical methods to characterise the genomic landscape associated with replicate hybrid zone formation. We studied two flower colour varieties of the common snapdragon, Antirrhinum majus subspecies majus, that form secondary hybrid zones in multiple independent valleys in the Pyrenees. Consistent with past work, we found very low differentiation at one well-studied zone (Planoles). However, at a second zone (Avallenet), we found stronger differentiation and greater heterogeneity, which we argue is due to differences in the amount of introgression following secondary contact. Topology weighting of genealogical trees identified loci where haplotype diversity was associated with the two snapdragon varieties. Two of the strongest associations were at previously identified flower colour loci: Flavia, that affects yellow pigmentation, and Rosea/Eluta, two linked loci that affect magenta pigmentation. Preliminary analysis of coalescence times provides additional evidence for selective sweeps at these loci and barriers to gene flow. Our study highlights the impact of demographic history on the differentiation landscape, emphasizing the need to distinguish between historical divergence and recent introgression.

evolutionary biology↗

bioRxiv2025

Population Genomics of Giant Mice from the Faroe Islands: Hybridization, Colonization, and a Novel Challenge to Identifying Genomic Targets of Selection

Populations that colonize islands provide unique insights into demography, adaptation, and the spread of invasive species. House mice on the Faroe Islands evolved exceptionally large bodies after colonization, generating interest from biologists since Darwin. To reconstruct the evolutionary history of these mice, we sequenced genomes of population samples from three Faroe Islands (Sandoy, Nolsoy, and Mykines) and Norway as a mainland comparison. Mice from the Faroe Islands are hybrids between the subspecies Mus musculus domesticus and M. m. musculus, with ancestry alternating along the genome. Analyses based on the site frequency spectrum of single nucleotide polymorphisms and the ancestral recombination graph (ARG) indicate that mice arrived on the Faroe Islands on a timescale consistent with transport by Norwegian Vikings, with colonization of Sandoy likely preceding colonization of Nolsoy. Substantial reductions in nucleotide diversity and effective population size associated with colonization suggest that mice on the Faroe Islands evolved large body size during periods of heightened genetic drift. Genomic scans for positive selection uncover windows with unusual site frequency spectra, but this pattern is mostly generated by clusters of singletons in individual mice. Variants showing evidence of selection in both Nolsoy and Sandoy based on the ARG are enriched for genes with neurological functions. Our findings reveal a dynamic evolutionary history for the enigmatic mice from Faroe Island and emphasize the challenges that accompany population genomic inferences in island populations. Significance StatementPopulations that colonize islands are expected to have unusual histories compared to their mainland counterparts. Using population genomic data, we conclude that giant mice living on the Faroe Islands originated from hybrids, invaded the islands on a timescale consistent with transport by Vikings, and persisted despite drastic reductions in population size. We also uncover a novel challenge to scanning genomes for genes involved in adaptation.

evolutionary biology↗

bioRxiv2024

The fourspine stickleback (Apeltes quadracus) has an XY sex chromosome system with polymorphic inversions on both X and Y chromosomes

Teleost fish are well-known for possessing a diversity of sex chromosomes and for undergoing frequent turnovers of these sex chromosomes. However, previous studies have mainly focused on variation between species, while comparatively little attention has been given to sex chromosome polymorphisms within species, which may capture early stages of sex chromosome changes. To better understand the evolution of sex chromosomes, we used the fourspine stickleback (Apeltes quadracus) as a model organism. Previously, it was believed that females of this species possessed a ZW heteromorphic sex chromosome system. However, genetic crosses and our whole-genome sequencing of wild populations revealed that A. quadracus has an XY sex chromosome on chromosome 23. This chromosome has not previously been identified as a sex chromosome in other stickleback species, indicating a recent sex chromosome turnover. We also identified two genes - rxfp2a and zar1l - as novel candidate sex determination genes. Notably, we observed inversions on both the X and Y chromosomes in different populations, resulting in distinctive patterns of differentiation between the X and Y chromosomes across populations. We propose that the inversion on the X chromosome may have been favored by sexually antagonistic selection. The new sex chromosome and intraspecies inversion polymorphisms observed in A. quadracus provide an excellent system for studying the evolution of sex chromosomes and their turnovers. Author SummaryAs compared to mammals and birds, teleost fish exhibit a very high level of diversity in their sex chromosomes, even among closely related species. Thus far, little attention has been paid to variation within species, although it offers a valuable opportunity to advance our understanding of the mechanisms underlying the formation and turnover of sex chromosomes. Through a quantitative trait locus (QTL) cross and sequencing diverse populations, we determined that instead of the previously reported ZW system, A. quadracus has an XY sex determination system on chromosome 23. Within the sex determining region, we identified rxfp2a and zar1l as putative sex determining genes. Notably, we also observed polymorphic inversions present on both the X and Y chromosomes that differ among populations. Based on our findings, we hypothesize that the X-linked inversions are favored by selection that differs between males and females. These observations represent a rare situation in which sex chromosomes are still polymorphic for sex-linked inversions, which offers important insights into the early stages of sex chromosome evolution.

evolutionary biology↗

bioRxiv2024

Emergence and host range expansion of an epidemic lineage of Ralstonia solanacearum

The evolutionary processes underlying disease outbreaks remain unknown for most bacterial plant pathogens. We sequenced an outbreak of lethal wilt disease in Martinique caused by two distantly related lineages in the Ralstonia solanacearum species complex. One lineage (R. solanacearum IIB-4NPB) exhibited the broadest host range ever documented for a single lineage in the field, while the other (R. pseudosolanacearum I-18) expanded in parallel but retained specialisation on solanaceaous hosts. Phylogenomic analysis of 407 outbreak isolates shows both lineages independently disseminated from mainland populations into Martinique. We resolved fine-scale geographic patterns of genomic diversity and identified spatial hotspots of interspecies mobile element exchange, resulting in the identification of a new family of Ralstonia integrative conjugative elements (ICEs) associated with the outbreak. ICE accessory gene integration sites display striking functional specialization and differentiation despite variable gene content: each site acquires only metabolism-associated or defence-related genes, respectively. This work provides insight into the origin and genomic changes associated with an outbreak of plant disease, and highlights the role of mobile elements in driving pathogen emergence.

microbiology↗

bioRxiv2024

Genetic determinants of distinct CD8+ α/β-TCR repertoires in the genus Mus

The adaptive immune systems efficacy relies on the diversity of T cell receptors and the ability to distinguish between self and foreign antigens. Analysis of the paired heterodimeric {beta}-TCR chains of individual T cells requires single-cell resolution, but existing single-cell approaches offer limited coverage of the vast TCR repertoire diversity. Here we introduce CITR-seq, a novel, instrument-free, high-throughput method for single-cell TCR sequencing with >88% {beta}-TCR pairing precision. We analyzed the TCR repertoires of CD8+ T cells originated from 32 inbred mice using CITR-seq, comprising four evolutionary divergent sister species and their F1 hybrids. Overall, we identified more than 5 million confidently paired TCRs. We found that V(D)J gene usage patterns are highly specific to the genotype and that V{beta}-gene usage is strongly impacted by thymic selection. Using F1 hybrids, we show that differences in gene segment usage across species are likely caused by cis-acting factors prior to thymic selection, which imposed strong allelic biases. At the greatest divergence, this led to increased rates of TCR depletion through rejection of particular V{beta}-genes. TCR repertoire overlap analysis across all mice revealed that sharing of identical paired CDR3 amino acid motifs is four times more frequent than predicted by random pairing of TCR and TCR{beta} chains, with significantly increased sharing rates among related individuals. Collectively, we show that beyond the stochastic nature of TCR repertoire generation, genetic factors contribute significantly to the shape of an individuals repertoire.

genomics↗

bioRxiv2024

Distinct evolution at TCRα and TCRβ loci in the genus Mus

T cells recognize an immense spectrum of pathogens to initiate immune responses by means of a large repertoire of T cell receptors (TCRs) that arise from somatic rearrangements of variable, diversity and joining gene segments at the TCR loci. These gene segments have emerged from a limited number of ancestral genes through a series of gene duplication events, resulting in a greatly variable number of such genes across different species. Apart from the complete V(D)J gene annotations in the human and mouse reference assemblies, little is known about the structure of TCR loci in other species. Here, we performed a comprehensive comparison of the TCR and TCR{beta} gene segment clusters in mice and three of its closely related sister species. We show that the TCR variable gene cluster is frequently rearranged, leading to deletions and sequence inversions in this region. The resulting complexity of TCR loci severely complicates the assembly of these loci and the annotation of gene segments. By jointly utilizing genomic and transcriptomic data, we show that in Mus musculus castaneus the variable gene cluster at the locus has undergone a recent major locus contraction, leading to the loss of 74 variable gene segments. Additionally, we validated the expression of functional variable genes, including atypical ones with inverted orientation relative to other such segments. Disentangling the fine-scale structure of TCR loci in different species can provide valuable insights in the evolution and diversity of TCR repertoires.

genomics↗

bioRxiv2024

Introgression dynamics of sex-linked chromosomal inversions shape the Malawi cichlid adaptive radiation

Chromosomal inversions contribute to adaptive speciation by linking co-adapted alleles. Querying 1,375 genomes of the species-rich Malawi cichlid fish radiation, we discovered five large inversions segregating in the benthic subradiation that each suppress recombination over more than half a chromosome. Two inversions were transferred from deepwater pelagic Diplotaxodon via admixture, while the others established early in the deep benthic clade. Introgression of haplotypes from lineages inside and outside the Malawi radiation coincided with bursts of species diversification. Inversions show evidence for transient sex linkage and a striking excess of protein changing substitutions points towards selection on neuro-sensory, physiological and reproductive genes. We conclude that repeated interplay between depth adaptation and sex-specific selection on large inversions has been central to the evolution of this iconic system.

evolutionary biology↗

bioRxiv2024

Diversifying selection and adaptive introgression of carotenoid-processing genes underlie the evolution of bill color in the long-tailed finch

Carotenoid pigmentation produces the yellow and red coloration of birds and other vertebrates, but our understanding of the genetic architecture of carotenoid ornamentation is largely limited to studies of novel color variants observed in captively bred populations. The complexity of carotenoid-based color evolution in nature remains poorly characterized. Here, we examine the long-tailed finch Poephila acuticauda, an Australian songbird with two hybridizing subspecies that differ in bill coloration: yellow in western subspecies acuticauda and red in eastern subspecies hecki. We characterize the carotenoid composition of each subspecies and find that yellow bills can be explained by the loss of C(4)-oxidation, thus blocking yellow dietary pigments from being metabolized to red. Combining linked-read genomic sequencing and reflectance spectrophotometry measurements of bill color collected from wild-sampled finches and laboratory crosses, we identify four loci that together explain 53% of variance in this trait. The two loci of largest effect contain the genes CYP2J19, an essential enzyme for the ketolation via C(4)-oxidation of dietary carotenoids, and TTC39B, an enhancer of ketocarotenoid production. Evolutionary genealogy reconstruction indicates that the red-billed phenotype is ancestral and yellow alleles at both CYP2J19 and TTC39B arose and fixed in acuticauda approximately 100 kya. Yellow alleles then introgressed into hecki less than 5 kya. Across all four loci, acuticauda derived variants show evidence of selective sweeps, implying that yellow bill coloration has been favored by natural selection. Our study suggests that the frequent adaptive evolutionary transitions between red and yellow ornamentation in nature can have a simple genetic basis. SignificanceWe studied variation in carotenoid ornamentation of an Australian songbird with two hybridizing subspecies that differ in bill color: one yellow and the other red. We identified a single metabolic process, C(4)-oxidation, underlying the distinct carotenoid composition of these two bill colors. Genetic association mapping revealed four major effect loci that explained most of the observed variation the trait, including the oxidative ketolation enzyme CYP2J19 and the carotenoid ketolation enhancer gene TTC39B. Evolutionary reconstruction indicates that yellow alleles are derived, ancient (~100 kya), and under positive selection. This has driven their recent (<5 kya) adaptive introgression across the hybrid zone. These findings have important implications for understanding the role of natural selection in phenotypic evolution in natural systems.

evolutionary biology↗

bioRxiv2024

Copy number normalization distinguishes differential signals driven by copy number differences in ATAC-seq and ChIP-seq

A common objective across ATAC-seq and ChIP-seq analyses is to identify differential signals across contrasted conditions. However, in differential analyses, the impact of copy number variation is often overlooked. Here, we demonstrated copy number differences among samples could drive, if not dominate, differential signals. To address this, we propose a pipeline featuring copy number normalization. By comparing the averaged signal per gene copy, it effectively segregates differential signals driven by copy number differences from other factors. Further applying it to Down syndrome, we unveiled distinct dosage-dependent and -independent changes on chromosome 21. Thus, we recommend normalization as a general approach.

genomics↗

bioRxiv2024

Flexible and high-throughput simultaneous profiling of gene expression and chromatin accessibility in single cells

Gene regulation underpins development and is an intricate biological process involving transcription, typically at promoters within accessible chromatin. To understand cell-type specific regulatory networks, the ability to capture both transcription and chromatin accessibility simultaneously is crucial. However, joint measurements are technically challenging and current methodologies still face adoption challenges. Here, we present easySHARE-seq, an improvement on SHARE-seq, for the simultaneous measurement of ATAC- and RNA-seq in single cells. We address several limitations of the previous method by improving the barcode and streamlining the protocol. As a result, easySHARE-seq libraries have a usable sequence of up to 300bp (+200bp increase), making it suitable for e.g. investigation of allele-specific signals or variant discovery. Furthermore, easySHARE-seq libraries do not require a dedicated sequencing run thus saving costs. We applied easySHARE-seq to murine liver nuclei and recovered 19,664 nuclei with joint chromatin and expression profiles. By benchmarking against other combinatorial indexing-based techniques, we showed we can recover over 1.5 fold more transcripts per cell while retaining high scalability and low cost. To showcase our method, we identified cell types, exploited the multiomic measurements to link cis-regulatory elements to their target genes and investigated liver-specific micro-scale changes. We conclude that easySHARE-seq improves upon previous methods and can produce high-quality multiomic datasets. We expect it to be applicable to a wide range of study designs.

genomics↗