Science

Despite recent climate change, many plants and animals are not yet tracking climate as predicted. We reconstruct realized climatic niches for 16 plants and 45 mammals across North America from the end of the last deglaciation to the present, calculating climate fidelity to measure temporal niche stability. Plants consistently exhibit higher climate fidelity than mammals, despite limited dispersal. During the deglaciation, which had lower human impact, some large mammals tracked warming climates as effectively as plants. Following European colonization, mammalian niches shifted markedly. Large mammals were displaced from warm, humid regions toward colder, drier areas, while some small mammals expanded into human-modified landscapes. In contrast, plant niches remained largely structured by climate, highlighting stronger anthropogenic constraints on mammalian responses to climate change thus far.

How a flexible mammalian embryo gives rise to a reproducible body plan remains unclear, partly because cell lineages cannot be followed continuously in vivo. We combined DNA Typewriter lineage recording with tetraploid complementation to reconstruct high-resolution single-cell genealogies across mouse development and built FateVec, an analysis framework that infers fate-bias dynamics and lineage-associated transcriptional programs from reconstructed phylogenies. Loss of developmental potential proved progressive and asynchronous, with multiple lineages acquiring detectable fate bias before morphological diversification at gastrulation. Within the neural crest, most cells remained multipotent over an extended window, while independent founder clades differed markedly in restriction timing. Extending lineage recording to a stem-cell-derived embryo model revealed that cells with shared transcriptional identities can arise from distinct lineage relationships. We further found embryonic-lineage contributions to extraembryonic-like states, exposing an unexplored lineage plasticity. This lineage-resolved view of embryogenesis reveals that cell identity alone predicts neither developmental ancestry nor the timing of fate restriction.

The heartbeat originates in the sinoatrial (SA) node, where spontaneously firing pacemaker myocytes interact to generate a coherent rhythm. The classical entrainment account is deterministic: the fastest cells entrain the rest, and variability is an error term that coupling suppresses. We proposed previously that the node instead exploits its own noise through stochastic resonance, with rhythm quality peaking at intermediate fluctuation amplitude, and since mapped a metabolic gradient capable of supplying it. Two-photon imaging of the voltage sensor ASAP5 in the intact mouse node resolved the subthreshold regime that tissue-scale mapping averages away. Diastolic coherence followed an inverted-U against endogenous noise amplitude in both poles, with optima 3.5-fold apart, and each pole operated near its own. {beta}-adrenergic stimulation raised noise in both poles to a common level. The inferior pole, which began below its optimum, gained coherence, while the superior pole, already at its optimum, lost interval regularity. Blocking HCN-mediated If with ivabradine lowered superior coherence without changing superior noise, and lowered inferior noise without lowering inferior coherence, dissociating the two coordinates. Thus, coherence is a surface defined by noise and coupled-clock drive. Phosphoinositide 4,5-bisphosphate (PIP2), an ATP-dependent lipid cofactor for HCN channels, increased firing rate and noise in both poles but improved coherence only in the energy-poor inferior node. Prior If block abolished that rescue. Pacemaking is therefore graded by a bioenergetic supply chain that sets the noise, not by entrainment alone. Noise, long treated as a nuisance to be averaged away, is an active ingredient of the pacemaker.

Mitochondrial DNA (mtDNA) mutations cause inherited disease, accumulate with age, and recur in tumors, yet their effects remain unresolved because existing models interrogate one engineered allele at a time. We developed mtDIVE, a random C[->]T mutagenesis platform for pooled mitochondrial forward genetics in human epithelial cells and zebrafish embryos. mtDIVE generates genotypes ranging from single substitutions to >100 mutations per molecule, impairs respiration, and causes lineage-specific developmental delay. Coupling single-cell transcriptomics with mtDNA genotyping revealed that selection on mutant genomes and their transcriptional consequences depend on metabolic state and developmental lineage. Obligate OXPHOS eliminates highly mutated cells by apoptosis, whereas glycolytic conditions promote their competitive displacement. Individual loci exert modest but non-redundant effects that predict cell state beyond aggregate mutation burden, and cancer-recurrent variants are enriched among mutations linked to reduced mitochondrial transcription. Thus, mtDIVE links mtDNA genotypes to cellular phenotypes, separating the consequences of mutation identity from mutational load.

Hematophagy has arisen independently many times across Metazoa, and recurrent anticoagulant protein families in blood-feeders are often read as convergent recruitment - the Kunitz/BPTI domain a paradigm case, with the leech an oft-cited low-Kunitz exception. We re-examine this at the gene level and ask whether a confirmatory cross-phylum test of this blood-feeding/anticoagulant association is feasible with public genomes. Applying an auditable gene-level protocol (one longest-isoform representative per gene; conservation-checked protein to gene mapping) to eight metazoan lineages, we find no consistent, universal elevation of whole-genome gene-level Kunitz-repertoire size in these blood-feeders (blood-feeder median 18 genes vs non-blood-feeder median 39; a descriptive comparison of non-independent taxa, not a formal test). Protein-entry counts inflate gene-level Kunitz counts by up to ~4.6x (mosquito 23 to 5), and neither this inflation nor proteome-wide isoform density (1.0-2.7x) tracks diet, so protein-entry comparisons are an unreliable basis for repertoire claims. Separately, deterministic bookkeeping under a fixed topology and a no-reversal rule counts 12 independent blood-feeding origins (11 if the ancestral lamprey is treated as parasitic with two losses); a non-exhaustive screen of annotated public genomes yielded only one candidate blood/non-blood pair (bedbug), and, under the pre-registered simulation scenario, only a cross-origin heterogeneity endpoint is attainable within a realistic origin ceiling, and only under strong heterogeneity (among-origin SD >= 3-4). An exploratory, feasibility-grade secretome-composition estimate did not meet the pre-registered criterion. We offer a gene-level, annotation-aware re-analysis, a caution about isoform/annotation bias in cross-phylum comparisons, and an account of what current data can and cannot support.

Around 6700 BP (years before present), Neolithic Europe saw the emergence of megalithic monuments in northern France, followed by a rapid spread to the rest of the continent1. However, whether this was driven by the transmission of ideas (cultural diffusion) or the movement of people remains debated. To test whether this spread coincided with population movements, we reconstructed the population history of the European Neolithic ([~]6500-4800 BP) by analysing genomic data from 2963 ancient individuals, including 46 unpublished genomes from megalithic and related contexts. To assess the alternative scenario whereby megaliths spread through contact networks, as expected under cultural diffusion, we integrated archaeological evidence with radiocarbon chronologies to reconstruct past trading networks. We identify northern France, where megaliths first emerged, as a zone of genetic admixture and cultural influence from the two major early Neolithic divisions: the Cardial of the Western Mediterranean and the Linear Pottery traditions of central Europe. From this admixed population, we uncover several migrations associated with the formation of the Funnel Beaker Culture in north-central Europe and the neolithisation of Scandinavia and the British Isles. We find that megaliths were spread exclusively within regions impacted by Cardial-related genetic ancestry, but only in the British Isles and Ireland did their emergence coincide with the time of the migration. The temporal delay between the migrations and the spread of megaliths elsewhere reveals that neither population movements nor cultural diffusion alone fully explains the geospatial distribution of the megalithic tradition. Rather, megaliths diffused across different Neolithic groups whose long-distance trade networks formed in the wake of earlier population movements. Our findings highlight the need to move beyond simplistic interpretations that present migrations or cultural diffusion as isolated events bringing technological and cultural innovations.

Madagascar's extinct hippopotamuses were a distinctive component of the island's recently lost megafauna, yet their origins, diversification history, and taxonomy have remained unresolved. Here, we recover the first ancient mitochondrial genomes from Malagasy hippopotamuses, obtaining phylogenetic data from 37 subfossil specimens across seven localities and all three named species, and integrate these data with morphology and total-evidence phylogenetic analyses. The 35 endemic specimens form a single clade most closely related to Hippopotamus amphibius, supporting a single colonization of Madagascar. Within this radiation, five deeply divergent and geographically structured mitochondrial lineages diversified across most regions of Madagascar during the Pleistocene. Tip-dating estimates a remarkably young crown age of ~1.41 Ma, following divergence from mainland Hippopotamus at ~3.24 Ma. These lineages do not map cleanly onto traditional taxonomy: material assigned to H. lemerleispans several divergent clades, while H. laloumena and H. madagascariensis are nested within this broader diversity. Morphology supports some lineage assignments but also points to previously unrecognized diversity, while ancestral-state reconstruction supports early body-size reduction followed by a secondary increase in H. laloumena. Malagasy hippopotamuses therefore represent an exceptionally recent radiation of large-bodied island mammals (and the youngest in Madagascar), showing that Madagascar continued to generate endemic mammalian diversity well into the Pleistocene. Their late-Holocene extinction erased the product of more than a million years of rapid insular diversification, the drivers of which remain enigmatic.

Plants explore soil environments through their roots, which branch repeatedly to access water and soil-borne nutrients. In many plants, root branches are generated by repeated developmental programs and molecular analyses have not identified markers that distinguish primary from later root branches. Consequently, efforts to engineer plant roots for improved water or nutrient acquisition are limited to changes that affect the entire root system. Here, we developed synthetic genetic circuits to count repeating root development cues and enable differential gene expression in successive root branches of the model plant Arabidopsis thaliana. The circuits use a root primordium-specific promoter to express large serine recombinases, which irreversibly invert segments of DNA each time a new lateral root is initiated. This converts repeating rounds of root formation into distinct, heritable DNA states. Because root branch specification and outgrowth occur over a ~2 day period, we tested circuit designs for their ability to count long-duration input pulses and developed an architecture that produces distinct fluorescence outputs in primary, secondary, and tertiary roots. By linking repeated developmental cues to distinct genetic outputs, synthetic genetic circuits that count enable root system engineering at the resolution of individual branches and offer a general strategy for dissecting developmental processes that rely on repeated signals.

Creating highly active enzymes for arbitrary reactions is a transformative goal for the molecular sciences (1). Traditional protein engineering (2,3) is constrained by a reliance on existing natural starting points, which are often challenging to discover. De novo design offers the potential to overcome this by creating enzymes from first principles (4), but has yet to achieve practically relevant catalytic properties. Here we present AlphaProtein Novo (AP Novo), a machine-learning pipeline that demonstrates, for the first time, that de novo enzyme design can outperform natural sequence mining in addressing challenging chemistry. We used AP Novo to design new-to-nature nitrene transferases to synthesise the pharmacophore piperidine with unprecedented product selectivity, and to create enzymes that degrade the environmental toxin DEHP under conditions that denature natural enzymes. We also obtained state-of-the-art catalytic efficiencies on two well-studied model reactions, and through iterative design and analysis found that key enablers of success were mechanism-inspired metrics based on AlphaFold 3 predictions and sequence-ensemble-based scoring of designed backbones. Our results show that de novo design has become a powerful complement to natural enzyme diversity for discovering catalysts for a range of applications.

Centromeres evolved at the root of eukaryotes to segregate chromosomes during cell division. Despite their ancient origin, centromeric DNA sequences evolve rapidly and adopt diverse architectures, including point centromeres, satellite arrays, transposon clusters, and holocentrics. To analyse centromere evolution at a broad scale, we characterised architectures across 325 diverse Darwin Tree of Life genome assemblies. Centromere architecture is evolutionarily labile, and similar configurations arise independently across divergent lineages. In plants and animals, we modelled centromere evolution as a recurrent cycle, in which satellite- and transposon-based architectures interconvert, with independent origins of holocentricity. We curated >23 million satellite repeats comprising 263 families from 165 species. Despite sequence divergence between satellite families, higher order repeats are prevalent, indicating constraint on repeat architecture rather than primary sequence. Satellite arrays are heavily invaded by diverse transposon families, consistent with convergent adaptation to the centromeric niche. In 89 species, transposons themselves constitute the primary centromere structure. We observed centrophilic transposons forming tandem arrays, suggesting mechanisms for satellite regeneration. Our sample includes five independent origins of holocentricity in plants and animals, which vary in association with periodic satellite arrays. We propose that genetic instability, centrophilic transposition, and transmission distortion promote recurrent centromere architectural interconversions during evolution.

Ayahuasca, used religiously for centuries by Amazonian Indigenous peoples and increasingly studied for its therapeutic potential, owes its psychoactivity to two plants: Psychotria viridis supplies N,N-dimethyltryptamine (DMT), whereas Banisteriopsis caapi supplies beta-carbolines that render DMT orally active. Here we show that the two plants have distinct genome histories: P. viridis is hexaploid (2n = 6x = 66), consistent with autopolyploidy, and B. caapi is diploid (2n = 2x = 20). CENH3-bound regions of both species are nonetheless enriched in CRM-type Ty3/Gypsy retrotransposons, with additional LINE elements and CRM-derived satellites in B. caapi. In P. viridis, a single multifunctional methyltransferase catalyzes both N-methylations of tryptamine to DMT. In B. caapi, beta-carboline biosynthesis combines dedicated enzymes with an acetaldehyde-dependent Pictet-Spengler cyclization that can proceed non-enzymatically, followed by enantioselective oxidation to harmaline. These resources link the ethnobotanical history of ayahuasca to its molecular basis, providing genomes of both source plants, the genetic structure of traditionally recognized cultivated varieties, and the enzymes behind the alkaloids long combined in this decoction.

Transposable elements are a major source of gene-regulatory functions. Yet this contribution is understood largely from ancient insertions already fixed in the genome: the successes, seen long after the fact. The polymorphic phase before fixation or loss remains poorly resolved because such alleles could be scored only as present or absent. We resolved segregating transposable-element alleles as sequences, epigenetic states, and transcript components using 231 haplotype-resolved human pangenomes with matched long-read multi-omics. Their origins extend beyond recent transposition; their regulatory consequences depend on methylation and transcript context and are often missed by gene-level analyses; they provide mechanisms at trait-associated loci, while selection favors element presence and absence alike. Regulatory innovation before fixation is therefore not one-way accumulation, but a mixture of gain, remodeling, and loss.

Africa hosts remarkable biodiversity across diverse biomes, yet its evolutionary history at continental-scale remains poorly understood. We integrate a time-calibrated phylogeny covering 93% of African vascular plant genera with continental-scale distribution data to jointly evaluate phylogenetic diversity (PD), endemism, and diversification rates (DR). We reveal a pronounced decoupling between DR and accumulated evolutionary history across Africa. Mountain, arid, and semi-arid areas emerge as centers of neo-endemism and elevated diversification, whereas lowland and humid regions, particularly the Guineo-Congolian zone, are dominated by older lineages with low recent diversification. Several DR hotspots do not overlap with Global Biodiversity Hotspots, indicating a mismatch between rapid diversification and accumulated evolutionary history. High net diversification and speciation rates during the last 15 million years were likely driven by cooling, aridification, and mountain uplift that created new ecological gradients and isolation barriers. These abiotic changes, interacting with lineage-specific traits, shaped African modern flora and highlight conservation gaps, especially in arid regions

Light-cycle time-restricted feeding disrupts daily cardiovascular and thermoregulatory rhythms, but the molecular effects of light-cycle time-restricted feeding on the heart have been measured only at the level of total gene expression. We used Oxford Nanopore long-read RNA sequencing to resolve the full-length ventricular transcriptome from male and female mice under ad libitum feeding or light-cycle time-restricted feeding across the 24-hour cycle. Greater than 20% of cardiac transcripts represent unannotated variants of known genes absent from the current GENCODE reference annotation. Light-cycle time-restricted feeding reorganizes transcript usage across hundreds of genes, including genes encoding splicing regulators, largely without changing total gene expression. The genes affected are sex-specific, with fewer than 2% of changes shared at the gene, transcript, and transcript-usage levels. We show that transcript-level regulation is a previously underrecognized component of the cardiac response to altered feeding behavior, undetected by conventional short-read approaches.

A hallmark of chromosomal inversions is that they suppress recombination between haplotypes, allowing inversion haplotypes to persist as single co-inherited units. To determine the extent to which inversions nevertheless permit genetic exchange, we investigated a common 979-kb inversion polymorphism at the human 17q21.31 locus. This locus exhibits deep divergence between the reference (H1) and inverted (H2) haplotypes, extensive segmental duplications (SDs) flanking the inversion, and association with neurodegenerative diseases, developmental disorders, and fertility-related phenotypes. Using single-cell sperm genome sequencing data, we directly measured recombination rates between H1 and H2 haplotypes and found near-complete suppression of single-crossover events between the haplotypes. The rare single crossovers that did occur were mediated by non-allelic homologous recombination between shared H1 and H2 SDs, generating novel duplication architectures. In contrast, two-switch events consistent with gene conversion or double crossovers, spanning 17-150 kb, occurred throughout the inversion at rates exceeding genome-wide estimates for events of comparable size. Consistent with recurring genetic exchange, we identified 99 distinct H1-H2 recombinant haplotypes segregating in All of Us genomes, including 26 with combinations of H1 and H2 SDs. These recombinant haplotypes facilitated dissection of the inversion's effects on fertility-related phenotypes; using a large parent-embryo dataset, we found that H2 additively increases female crossover rates across chromosomes and that KANSL1 duplications do not explain this effect. Finally, ancestral recombination graphs dated H1-H2 gene flux (the exchange of genetic material between alternative arrangements) to approximately 100-500 thousand years ago, revealing that H1 and H2 haplotypes have co-segregated for at least half a million years. Together, these results demonstrate that inversions can be permeable barriers to recombination, with ongoing gene flux influencing the diversity and evolution of inversion polymorphisms.

With a sub-3-micrometer cell and a 27-Mbp diploid genome, the small but mighty Picochlorum celeri doubles within three hours and exceeds 30 g m-2 d-1 outdoors with CO2 supplied. In climate-simulating photobioreactors, productivity declined from 39 g m-2 d-1 under 2.25% CO2 to near zero in air and resumed within hours of CO2 restoration with photosystem II photochemistry largely retained. We profiled the transcriptome, proteome, phosphoproteome, ubiquitinome, acetylome, metabolome and lipidome, including the first site-resolved green-algal ubiquitinome. In air, the Rubisco large subunit tripled to 7.6% of protein while its two small-subunit isoforms, 70% identical, exchanged near-reciprocally, a novel CO2-dependent switch that we propose retunes Rubisco to low CO2. Photorespiratory enzymes increased in abundance whereas proteins involved in external nitrogen assimilation decreased, consistent with increased reliance on internal nitrogen recycling as carbon fixation became limiting. Transcript and protein responses were nearly uncoupled, with cytosolic ribosomal proteins declining despite increased transcripts and plastid ribosomal proteins spared. Phosphorylation was extensively remodeled, as were the lysine modifications ubiquitination, acetylation and CO2-dependent carbamylation, where a CO2-competition assay identified 86 bicarbonate-protected lysines, including RbcL K252. CO2 limitation therefore imposes a reversible growth arrest that reduces cytosolic translational investment while preserving photosynthetic capacity for rapid recovery.

Ordinal scoring of plant disease severity by human raters compresses variation in lesion color, size, and number. Inter-rater variability further complicates comparisons and integrated analyses across environments. We developed a low-cost portable imaging chamber to rapidly image large numbers of leaves under standardized lighting, orientation, and backdrops in the field and employed this system to image more than 11,000 leaves across three states. Embeddings from vision encoders predicted human-assigned disease severity scores. No significant GWAS hits were identified using human-assigned or vegetation-index-based disease severity scores, but GWAS using embeddings identified twelve genomic hotspots controlling leaf appearance. Nine were linked to variation in disease symptom severity. Five hotspots corresponded to previously characterized sorghum genes: all three hotspots not linked to disease and two of the nine that were. Roughly one-third of tested embedding--hotspot associations replicated across at least two states, and twenty replicated across all three. eQTL, PheWAS, and large-effect variant analyses identified single candidate genes with plausible mechanistic links to disease symptom severity for six of the seven hotspots not mapping to characterized genes. These results demonstrate the power of combining scalable, standardized leaf imaging with pretrained image encoders to capture genetically controlled variation in diverse disease symptoms that human ordinal scoring misses.

Aerial roots of certain maize (Zea mays) and sorghum (Sorghum bicolor) genotypes secrete a carbohydrate-rich mucilage that sustains nitrogen-fixing bacteria, and the underground roots of most plants secrete mucilage at their tips. In both settings, border cells released from the root cap produce this mucilage, yet the genes controlling their formation remain largely unknown. We sequenced the RNA of about 23,000 nuclei from mucilage-secreting roots of maize, sorghum, and Medicago truncatula, sampled before and after secretion. Each species yielded 10 to 15 clusters, which we annotated with published markers and with new markers that we validated by in situ hybridization in the two cereals and by promoter-reporter fusions in M. truncatula. We then inferred modular and cell type-specific gene regulatory networks. Transcriptional programs diverged across the three species except in the quiescent center and the meristem, and in the clusters containing border cells, where a shared set of regulators emerged. Silencing three of five candidate regulators reduced border cell number, while silencing a partially overlapping set of three regulators reduced root diameter in M. truncatula. Silencing the C2H2 zinc finger protein MtrunA17_Chr1g0148421 also reduced border cell viability. A maize insertion mutant of bzip89 released fewer border cells than the wild type. These networks offer entry points for tuning mucilage production in cereal and legume crops.

The mesoderm coordinates organogenesis and generates the cardiovascular, visceral and musculoskeletal systems, yet in mammals this germ layer is difficult to access, impeding its genetic manipulation and study. Here, we establish embryonic day (E) 7.5 exocoelomic cavity nano-injection as a scalable route for selective genetic targeting of mouse mesoderm. Combining in utero lentiviral barcoding with single-cell and spatial transcriptomics, we reconstructed mesodermal and neural crest clonal relationships across >590,000 cells and 31,000 multicellular clones from E9.5-E10.5 embryos and E16.5 livers and hearts. In liver, capsular mesothelium was closely related to hepatic stellate cells, whereas fibroblast and vascular smooth muscle lineages diverged earlier. In heart, epicardium was clonally coupled to three spatially restricted mesenchymal sub-lineages but not to cardiomyocytes, and lineage tracing separated epicardial- and neural crest-derived populations within transcriptionally convergent valve mesenchyme. This approach enables Cre-independent manipulation of mammalian mesoderm and resolves organ mesenchyme development at clonal resolution.

Cell-type atlases now catalogue hundreds of distinct human cell identities across development, each annotated with mitochondrial abundance, dominant fuel pathway, and lineage of origin, yet no computable model connects the topology of the lineage tree to the metabolic rate the resulting organs display in the adult body. Using a curated 396-node human cell-lineage tree spanning the zygote to terminal somatic identities, we test whether organ-level standard metabolic rate (SMR) is better predicted by developmental time (lineage depth) or by terminal fate identity (anatomical compartment). We find that lineage depth explains essentially none of the variance in a cell's metabolic tier (r = 0.11, R2 approximately 1.2%), whereas compartment identity explains roughly three-quarters of it (approximately 75%), and that the mean mitochondrial volume fraction of an organ's constituent terminal cell types tracks the organ's classical literature-derived SMR with r = 0.90 across five canonical reference-man organ groups. These results motivate a five-layer computable framework: lineage as a formal tree grammar, information-theoretic structure of the tree, metabolic switches as runtime operators, compilation to organ-level energetic networks, and execution as organism-level bioenergetics. We also introduce the metabolic commitment-horizon model: the hypothesis that a cell's metabolic tier is fixed at a discrete lineage-commitment event and thereafter held constant, rather than accumulated continuously with differentiation time. In a worked held-out test (5-fold cross-validation, n = 396), a nearest-commitment-ancestor predictor beat a global-mean null (MAE 0.752 vs 0.809, p = 0.015) but was not significantly better than a lineage-depth regression (delta MAE = -0.042, 95% CI -0.098 to +0.012, p = 0.175), so we report the commitment-horizon model as supported descriptively but not yet discriminated predictively on these data. We connect this within-species result to the classical, cross-species rate-of-living hypothesis, treat insulin resistance as an acquired perturbation of the clock, survey machine-learning and deep-learning tools that could extend the framework on primary single-cell data, and close with eight testable predictions and falsification conditions.