Find research datasets worth reusing

The genetic basis of plumage coloration and elevation adaptation in a clade of recently diverged alpine and arctic songbirds

Trait genetic architecture plays an important role in the probability that variation in that trait leads to divergence and speciation. In some cases, speciation may be driven by the generation of novel phenotypes through the recombination of genes associated with traits that are important for local adaptation or sexual selection. Here, we investigate the genetic basis of three plumage color traits, and one ecological trait, breeding elevation, in a recent avian radiation, the North American rosy-finches (Leucosticte spp.). We identify unique genomic regions associated with each trait and highlight 11 candidate genes. Among these are well-characterized melanogenesis genes, including Mitf and Tyrp1, and previously reported hypoxia-related genes including Egln1. Additionally, we use mitochondrial data to date the divergence of rosy-finch clades which appear to have diverged within the past 250 ky. Given the low levels of genome-wide differentiation among rosy-finch taxa, and evidence for extensive introgression in North America, plumage coloration and adaptation to high elevations have likely played large roles in generating the observed patterns of lineage divergence. The relative independence of these candidate regions across the genome suggests that recombination might have led to multiple phenotypes, and subsequent rosy-finch speciation, over short periods of time.

Data and R scripts for: Effects of hunting on genetic diversity, inbreeding and dispersal in Finnish black grouse (Lyrurus tetrix)

While intensive hunting activities, such as commercial fishing and trophy hunting, can have profound influences on natural populations, less intensive recreational hunting can also have more subtle effects on animal behaviour, habitat use and movement, with implications for population persistence. Lekking species such as the black grouse (Lyrurus tetrix) may be especially prone to hunting as leks are temporally and spatially predictable, making them easy targets. Furthermore, inbreeding in black grouse is mainly avoided through female-biased dispersal, so any disruptions to dispersal caused by hunting could lead to changes in gene flow, leading to an increasing risk of inbreeding. We therefore investigated the impact of hunting on genetic diversity, inbreeding and dispersal on a metapopulation of black grouse in Central Finland. We genotyped 1,065 adult males and 813 adult females from twelve lekking sites (six hunted, six unhunted) and 200 unrelated chicks from seven sites (two hunted, five unhunted) at up to thirteen microsatellite loci. Our initial confirmatory analysis of sex-specific fine-scale population structure revealed little genetic structure in the metapopulation. Levels of inbreeding did not differ significantly between hunted and unhunted sites in both adults and chicks. However, immigration rates into hunted sites were significantly higher among adults compared to immigration into unhunted sites. We conclude that the influx of migrants into hunted sites may compensate for the loss of harvested individuals, thereby increasing gene flow and mitigating inbreeding. Given the absence of any obvious potential barriers to gene flow in Central Finland, a spatially heterogeneous matrix of hunted and unhunted regions may be crucial to ensure sustainable harvests into the future.

Data for: Limited host availability disrupts the genetic correlation between virulence and transmission

Virulence is expected to be linked to parasite fitness via transmission. However, it is not clear whether this relationship is genetically determined, nor if it differs when transmission occurs continuously during, or only at the end of, the infection period. Here, we used inbred lines of the macro-parasitic spider mite Tetranychus urticae to disentangle genetic vs non-genetic correlations among traits, while varying parasite density and opportunities for transmission. A positive genetic correlation between virulence and the number of transmitting stages produced was found under continuous transmission. However, if transmission occurred only at the end of the infection period, this genetic correlation disappeared. Instead, we observed a negative relationship between virulence and the number of transmitting stages, driven by density dependence. Thus, within-host density dependence caused by reduced opportunities for transmission may hamper selection for higher virulence, providing a novel explanation as to why limited host availability leads to lower virulence.

Data for: Geographic isolation reduces genetic diversity of a wide-ranging terrestrial vertebrate, Canis lupus

Genetic diversity is theorized to decrease in populations closer to a species' range edge, where habitat may be suboptimal. However, generalist species capable of long-range dispersal may maintain sufficient gene flow to counteract this, though the presence of significant barriers to dispersal (e.g., large water bodies, human-dominated landscapes) may still lead to, and exacerbate, the edge effect. We used microsatellite data for 2,426 gray wolves (Canis lupus) from 24 sub-populations (groups) to model how allelic richness and expected heterozygosity varied with two measures of range edge (mainland-island position, latitude, and distance from range center) across >7.3 million km2 of northern North America. We found that allelic richness and expected heterozygosity of island groups was measurably less than that of mainland groups and that these differences increased with the island's distance to the species' range center in the study area. Our results demonstrate how multiple axes of geographic isolation (distance from range center and island habitation) can act synergistically to erode the genetic diversity of wide-ranging terrestrial vertebrate populations despite the counteracting influence of long-range dispersal ability. These findings emphasize how geographic isolation is a potential threat to the genetic diversity and viability of terrestrial vertebrate populations even among species capable of long-range dispersal. This dataset is comprised of four separate sub-datasets, sourced from Carmichael et al. (2007), Musiani et al. (2007), McNay (2006), and a manuscript in progress (referred to as "MacNulty" in the data files, to be first published in Frevol et al. 2023). The raw data are comprised of sample IDs, latitude and longitude points indicating where the sample was collected or recorded, and microsatellite genetic information. To aid in re-use, the raw genetic data has also been formatted and presented for use with common population genetics software (Genepop, MICROCHECKER, Genetix, FSTAT). The dataset also includes spatial data files of the sub-populations described in the study, allelic richness and expected heterozygosity data derived from the raw and spatial data, and the R script used to create the models. <ul> <li>Carmichael LE, Krizan J, Nagy JA, et al (2007) Historical and ecological determinants of genetic structure in arctic canids. Molecular Ecology 16:3466–3483. https://doi.org/10.1111/j.1365-294X.2007.03381.x</li> <li>McNay ME (2006) Preliminary results of parentage analysis using microsatellite markers from an exploited wolf population in central Alaska. Alaska Department of Fish and Game, Division of Wildlife Conservation, Juneau, Alaska</li> <li>Musiani M, Leonard JA, Cluff HD, et al (2007) Differentiation of tundra/taiga and boreal coniferous forest wolves: genetics, coat colour and association with migratory caribou. Molecular Ecology 16:4149–4170. https://doi.org/10.1111/j.1365-294X.2007.03458.x</li> </ul>

Integrating top-down and bottom-up approaches to understand the genetic architecture of speciation across a monkeyflower hybrid zone

Understanding the phenotypic and genetic architecture of reproductive isolation is a longstanding goal of speciation research. In several systems, large-effect loci contributing to barrier phenotypes have been characterized, but such causal connections are rarely known for more complex genetic architectures. In this study, we combine 'top-down' and 'bottom-up' approaches with demographic modeling toward an integrated understanding of speciation across a monkeyflower hybrid zone. Previous work suggests that pollinator visitation acts as a primary barrier to gene flow between two divergent red- and yellow-flowered ecotypes of Mimulus aurantiacus. Several candidate isolating traits and anonymous SNP loci under divergent selection have been identified, but their genomic positions remain unknown. Here, we report findings from demographic analyses that indicate this hybrid zone formed by secondary contact, but that subsequent gene flow was restricted by widespread barrier loci across the genome. Using a novel, geographic cline-based genome scan, we demonstrate that candidate barrier loci are broadly distributed across the genome, rather than mapping to one or a few 'islands of speciation.' Quantitative trait locus (QTL) mapping reveals that most floral traits are polygenic, with little evidence that QTL co-localize, indicating that most traits are genetically independent. Finally, we find little evidence that QTL and candidate barrier loci overlap, suggesting that some loci contribute to other forms of reproductive isolation. Our findings highlight the challenges of understanding the genetic architecture of reproductive isolation and reveal that barriers to gene flow aside from pollinator isolation may play an important role in this system.

Data from: Genetic architectures of postmating isolation and morphology of two highly diverged rockfishes (genus Sebastes)

Postmating isolation is thought to be an important driver of the late stages of speciation. However, relatively little is empirically known about the process compared to other isolating mechanisms that drive the early stages of speciation, especially in non-model organisms. We characterized the genetic architecture of postmating isolation between two rockfishes, Sebastes schlegelii and S. trivittatus, whose reproductive isolation is complete. We examined transmission ratio distortion (TRD) patterns of genetic markers in two reciprocal backcross populations. Markers showing either of the two types of TRD was widespread across the genome, with some of the distorted markers forming extensive clusters around the recombination coldspots. These suggest that the postmating isolation effectively prevents gene flow across the genome and the recombination landscape contributes to the genetic architecture. Comparisons between two backcross families and two developmental stages showed little similarity in the distorted markers, suggesting asymmetry and stage-specificity of the isolation. This may be due to hybrid incompatibility involving maternal factors or extrinsic selection. The lack of sex-ratio distortion in the mapping families suggested that Haldane's rule in terms of hybrid inviability does not hold. Additionally, QTL mapping detected significant QTLs for sex and the morphological traits relevant to speciation and convergence of rockfishes, including body coloration. Genes in the melanocortin system, including agouti-signaling protein 1 (asip1) and melanocortin 1 receptor (mc1r), might underlie the horizontal and vertical color patterns on the body, respectively. These findings constitute an essential step towards a comprehensive understanding of speciation and morphological diversification of rockfishes.

Data for: Species identification and population genetics of the Antarctic fish genera Lepidonotothen and Nototheniops (Perciformes, Notothenioidei)

Accurate species identification is essential to assess biodiversity and species richness in ecosystems threatened by rapid and recent environmental changes, such as warming in most Antarctic waters. The Lepidonotothen species complex comprises demersal notothenioid fishes which inhabit the shelf areas of the Antarctic Peninsula, the Scotia Arc and sub-Antarctic islands with a circum-Antarctic distribution. Species determination in this group has often been problematic. In particular, whether Lepidonotothen squamifrons and Lepidonotothen kempi are valid as separate species has been questioned. In this study, we analysed the genetic variation among four nominal southern polar species within this complex (L. kempi, L. squamifrons, Nototheniops larseni, Nototheniops nudifrons) by means of three different markers (ND2 and tRNA mitochondrial genes and a panel of 16 nuclear microsatellites). We tested whether individuals morphologically assigned to L. kempi showed genetic separation from L. squamifrons. Our analyses indicated a lack of differentiation between L. kempi and L. squamifrons. However, a genetically distinct population was found for L. squamifrons at the Shag Rocks islands near South Georgia. Antarctic and sub-Antarctic islands are known to be home to many cryptic species and further studies will elucidate if the genetically differentiated population we found potentially originated from this context and can be considered as an incipient species. Our analysis contributes to further characterize the species composition of the most abundant fish suborder in the Southern Ocean, which is amongst the regions most threatened by climate change.

Genetic assessment reveals inbreeding, possible hybridization, and low levels of genetic structure in a declining goose population

The population numbers of taiga bean goose (Anser fabalis fabalis) have halved during recent decades. Since this subspecies is hunted throughout most of its range, the decline is of management concern. Knowledge of the genetic population structure and diversity is important for guiding management and conservation efforts. Genetically unique subpopulations might be hunted to extinction if not managed separately, and any inbreeding depression or lack of genetic diversity may affect the ability to adapt to changing environments and increase extinction risk. We used microsatellite and mitochondrial DNA markers to study the genetic population structure and diversity among taiga bean geese breeding within the Central flyway management unit using non-invasively collected feathers. We found some genetic structuring with the maternally inherited mitochondrial DNA between four geographic regions (ɸST = 0.11-0.20) but none with the nuclear microsatellite markers (all pairwise FST-values 0.002- 0.005). These results could be explained by female natal philopatry and male-biased dispersal, which completely homogenizes the nuclear genome. Therefore, the population could be managed as a single unit. Genetic diversity was still at a moderate level (average HE = 0.69) and there were no signs of past population size reductions, although significantly positive inbreeding coefficients in all sampling sites (FIS = 0.05-0.10) and high relatedness values (r = 0.60-0.86) between some individuals could indicate inbreeding. In addition, there was evidence of either incomplete lineage sorting or introgression from the pink-footed goose (A. brachyrhynchus). The current population is not under threat by genetic impoverishment but monitoring in the future is desirable.

Genetic restoration of black rhinoceroses in South Africa: conservation implications

Globally, wildlife populations are becoming increasingly small and isolated. Both processes contribute to an elevated risk of extinction, notably due to genetic factors related to inbreeding depression and a loss of adaptive potential. Wildlife translocation is a valuable conservation tool to reintroduce species to previously occupied areas, or augment existing populations with genetically divergent animals, thereby improving the viability of endangered populations. However, understanding the genetic implications of mixing gene pools is key to avoid the risk of outbreeding depression, and to maximise translocation effectiveness. In this study we used mitochondrial and microsatellite DNA collected from 110 black rhinoceroses (Diceros bicornis minor) in Kruger National Park, South Africa, to determine levels of genetic diversity, inbreeding and relatedness. We compared this diversity with the two source populations (KwaZulu-Natal, South Africa and Zambezi River, Zimbabwe) using data from previously published studies, and assessed changes in the relative contribution of source lineages since their reintroduction in the 1970s. Our results show that Kruger's black rhinoceroses are genetically more diverse than those from KwaZulu-Natal, with levels closer to those from the Zambezi Valley. Furthermore, our findings indicate a relative increase in the Zimbabwean lineage since reintroduction, suggesting a possible selective advantage. From a conservation perspective, our results demonstrate the benefits of mixing multiple source populations to restore gene flow, improve genetic diversity and thereby help protect small, isolated populations from extinction.

opencc-by-4.0Oct 2022View details →

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Fig. 3 in Kyonemichthys rumengani (Teleostei: Syngnathidae) is Sister Taxon to the Pipefish Genus Urocampus: Genetic and Morphological Evidence

Fig. 3. Aquarium photograph of Kyonemichthys rumengani (OCF-P 10439, 25.6 mm SL).

Data from: Population connectivity patterns of genetic diversity, immune responses and exposure to infectious pneumonia in a metapopulation of desert bighorn sheep

Habitat fragmentation is an important driver of biodiversity loss and can be remediated through management actions aimed at maintenance of natural connectivity in metapopulations. Connectivity may protect populations from infectious diseases by preserving immunogenetic diversity and disease resistance. However, connectivity could exacerbate the risk of infectious disease spread across vulnerable populations. We tracked the spread of a novel strain of Mycoplasma ovipneumoniae in a metapopulation of desert bighorn sheep (Ovis canadensis nelsoni) in the Mojave desert to investigate how variation in connectivity among populations influenced disease outcomes. M. ovipneumoniae was detected throughout the metapopulation, indicating that the relative isolation of many of these populations did not protect them from pathogen invasion. However, we show that connectivity among bighorn sheep populations was correlated with higher immunogenetic diversity, a protective immune response and lower disease prevalence. Variation in protective immunity predicted infection risk in individual bighorn sheep and was associated with heterozygosity at genetic loci linked to adaptive and innate immune signalling. Together, these findings may indicate that population connectivity maintains immunogenetic diversity in bighorn sheep populations in this system and has direct effects on immune responses in individual bighorn sheep and their susceptibility to infection by a deadly pathogen. Our study suggests that the genetic benefits of population connectivity could outweigh the risk of infectious disease spread and supports conservation management that maintains natural connectivity in metapopulations.

opencc-by-4.0Jan 2023View details →

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Convergent genomics of longevity in rockfishes highlights the genetics of human lifespan variation

Longevity is a defining, heritable trait that varies dramatically between species. To resolve the genetic regulation of this trait, we have mined genomic variation in rockfishes, which range in longevity from 11 to over 205 years, along with the sea robin as an outgroup. We used the phylomapping methodology to target sequencing and assembly to conserved, functional loci, defined using available genomic resources from well-characterized species. These annotations are in the gtf. For analysis of coding elements, assembled contigs were trimmed to just the exons. Exons were concatenated and analyzed to generate gene trees with IQTree, fixed to match the species tree. Additional details of these assembly methods are available at DOI: <a href="https://doi.org/10.1038/s41559-019-0914-2">10.1038/s41559-019-0914-2</a> and <a href="https://doi.org/10.1126/sciadv.add2743">DOI: 10.1126/sciadv.add2743</a>

The population genetics of speciation by cascade reinforcement

Species interactions drive diverse evolutionary outcomes. Speciation by cascade reinforcement represents one example of how species interactions can contribute to the proliferation of species. This process occurs when the divergence of mating traits in response to selection against interspecific hybridization incidentally leads to reproductive isolation among populations of the same species. Here, we investigated the population genetic outcomes of cascade reinforcement in North American chorus frogs (Hylidae: Pseudacris). Specifically, we estimated the frequency of hybridization among three taxa, assessed genetic structure within the focal species, P. feriarum, and ascertained the directionality of gene flow within P. feriarum across replicated contact zones via coalescent modeling. Through field observations and preliminary experimental crosses, we assessed whether hybridization is possible under natural and laboratory conditions. We found that hybridization occurs among P. feriarum and two conspecifics at a low rate in multiple contact zones and that gene flow within the former species is unidirectional from allopatry into sympatry with these other species in three of four contact zones studied. We found evidence of substantial genetic structuring within P. feriarum including a divergent western allopatric cluster, a behaviorally-distinct sympatric South Carolina cluster, and several genetically-overlapping clusters from the remainder of the distribution. Furthermore, we found sub-structuring between reinforced and non-reinforced populations in the two most intensely-sampled contact zones. Our literature review indicated that P. feriarum hybridizes with at least five heterospecifics at the periphery of its range providing a mechanism for further intraspecific diversification. This work strengthens the evidence for cascade reinforcement in this clade, revealing the geographic and genetic landscape upon which this process can contribute to the proliferation of species.

Data from: Tree species and genetic diversity increase productivity via functional diversity and trophic feedbacks

This data was collected in the species × genetic diversity experiment of the Biodiversity–Ecosystem Functioning Experiment China Platform (BEF-China, <a href="http://www.bef-china.com/">www.bef-china.com</a>). This data set includes four species (Alniphyllum fortunei, Cinnamanum camphora, Daphniphyllum oldhamii, and Idesia polycarpa) with the mother trees of all tree individuals known, and the offspring from the same mother tree was defined as a seed family. In total, 92 subplots with 4 tree diversity levels were included: species diversity (1 or 4 species) and genetic diversity (1 or 4 seed families per species) which resulted in four tree diversity levels: one species with one seed family (1.1), one species with four seed families (1.4), four species with one seed family per species (4.1) and four species with four seed families per species (4.4). For tree functional traits, five leaf functional traits were measured in 2017 and 2018, including leaf area (LA), specific leaf area (SLA), chlorophyll content (CHL), leaf nitrogen content (LN), and leaf carbon content (LC). Herbivory was visually recorded as leaf damage in 2017. Soil fungal diversity was used as proxies for unspecified trophic interactions. Soil samples were taken on subplot level for the 1.1 and 1.4 diversity treatments, but on plot level for the 4.1 and 4.4 diversity treatments in 2017. Tree community productivity was summed by the biomass of individual trees in each subplot and individual tree biomass (kg) was calculated using the biomass equation (H × BA × CV) of the BEF-China experiment, where CV is a correction factor for stem shape and wood density.

The timings of host diapause and epidemic progression mediate host genetic diversity and future epidemic size in Daphnia-parasite populations

Epidemics commonly exert parasite-mediated selection and cause declines in host population genetic diversity. This could lead to evolution of resistance in the long-term and smaller subsequent epidemics. Alternatively, the loss of genetic diversity could increase host vulnerability to future disease spread and larger future epidemics. Matters are made more complex by the fact that a great many host organisms produce diapausing life stages in response to environmental change (often as a result of sexual reproduction) e.g., plant seeds and invertebrate resting eggs. These diapausing stages can disrupt the relationship between past epidemics, host genetic diversity and future epidemics because they allow host dispersal through time. Specifically, temporally dispersing hosts avoid infection and thus selection from contemporary parasites, and also archive genetic variation for the future. We studied 80 epidemics in 20 semi-natural populations of the temporally dispersing crustacean Daphnia magna and its sterilising bacterial parasite Pasteuria ramosa, and half of these populations experienced a simulated environmental disturbance treatment. We found that early initiation of diapause relative to the timing of the epidemic led to greater host genetic diversity and reduced epidemic size in the subsequent year, but this was unaffected by environmental disturbance.

Age-dependent genetic variation in aggression

Understanding the extent to which behavioural variance is underlain by genotypic, environmental and genotype-by-environment effects is important for predicting how behavioural traits might respond to selection and evolve. How behaviour varies both within and among individuals can change across ontogeny, leading to differences in the relative contribution of genetic and environmental effects to phenotypic variation across ages. We investigated among-individual and among-genotype variation in aggression across ontogeny by measuring, twice as juveniles and twice as adults, both approaches and attacks against a three-dimensional-printed model opponent in eight individuals from each of eight genotypes ( N = 64). Aggression was only significantly repeatable and heritable in juveniles. Additionally, how aggression changed between juvenile and adult life-history stages varied significantly among individuals and genotypes. These results suggest that juvenile aggression is likely to evolve more rapidly via natural selection than adult aggression and that the trajectory of behavioural change across the lifespan has the potential to evolve. Determining when genetic variation explains (or does not explain) behavioural variation can further our understanding of key life-history stages during which selection might drive the strongest or swiftest evolutionary response.

Immediate and long-term genetic consequences of linear transport infrastructure: Can fauna crossing mitigate its cost?

The genetic consequences of the subdivision of populations are regarded as significant to long-term evolution, and research has shown that the scale and speed at which this is now occurring is critically reducing the adaptive potential of most species which inhabit human-impacted landscapes. Here, we provide a rare, and to our knowledge, the first analysis of this process while it is happening and demonstrate a method of evaluating the effect of mitigation measures such as fauna crossings. We did this by using an extensive genetic dataset collected from a koala population which was intensely monitored during the construction of linear transport infrastructure which resulted in the subdivision of their population. First, we found that both allelic richness and effective population size decreased through the process of population subdivision. Second, we predicted the extent to which genetic drift could impact genetic diversity over time and showed that after only 10 generations the resulting two subdivided populations could experience between 12–69% loss in genetic diversity. Lastly, using forward simulations we estimated that a minimum of 8 koalas would need to disperse from each side of the subdivision per generation to maintain genetic connectivity close to zero but that 16 koalas would ensure that both genetic connectivity and diversity remained unchanged. These results have important consequences for the genetic management of species in human-impacted landscapes by showing which genetic metrics are best to identify immediate loss in genetic diversity and how to evaluate the effectiveness of any mitigation measures.

Spatial genetic differentiation correlates with species assemblage turnover across tropical reef fish lineages

Aim: Evaluating the similarity of diversity patterns across micro- to macroevolutionary scales in natural communities, such as species-genetic diversity correlations (SGDC), may inform on processes shaping community assembly. However, whether SGDCs not only hold across communities but also across lineages has never been explored so far. Here we investigated SGDCs across co-distributed taxa for different spatial components (α, β, γ), and formally tested the influence of dispersal traits on β SGDCs. Location: Western Indian Ocean Time period: 2016–2017 Major taxa studied: Tropical reef fish species with contrasting dispersal traits Methods: Using ddRADseq single nucleotide polymorphism (SNP) data for 20 tropical reef fishes and distribution data of 2,446 species belonging to 12 families, we analysed the correlations between within-species genetic diversity and within-family species diversity (i.e., lineage diversity) for the three spatial components (α, β, γ SGDCs). We then related the strength of β-SGDCs per species to proxies of larval dispersal abilities. Results: We detected positive and significant lineage-based SGDC only for the β component, i.e., the families showing the greatest level of species turnover among sites contains the species with the greatest levels of genetic differentiation. We showed that the Monsoon drift mainly explained the β diversity patterns at both intraspecific and interspecific levels. Higher β-SGDCs were found for species with short pelagic larval duration and weak larval swimming capacity. Main conclusions: Our study reveals a strong correlation between genetic and species β diversity, a result explained by the presence of a 'soft' barrier and mediated by larval dispersal processes. This suggests that vicariance and dispersal limitation are major processes shaping β-diversity patterns from microevolutionary to macroevolutionary scales in tropical reef fishes.

opencc-zeroFeb 2023View details →

A common resequencing‐based genetic marker dataset for global maize diversity

Maize (Zea mays ssp. mays) populations exhibit vast amounts of genetic and phenotypic diversity. As sequencing costs have declined, an increasing number of projects have sought to measure genetic differences between and within maize populations using whole genome resequencing strategies, identifying millions of segregating single-nucleotide polymorphisms (SNPs) and insertions/deletions (InDels). Unlike older genotyping strategies like microarrays and genotyping by sequencing, resequencing should, in principle, frequently identify and score common genetic variants. However, in practice, different projects frequently employ different analytical pipelines, often employ different reference genome assemblies, and consistently filter for minor allele frequency within the study population. This constrains the potential to reuse and remix data on genetic diversity generated from different projects to address new biological questions in new ways. Here we employ resequencing data from 1,276 previously published maize samples and 239 newly resequenced maize samples to generate a single unified marker set of ~366 million segregating variants and ~46 million high confidence variants scored across crop wild relatives, landraces as well as tropical and temperate lines from different breeding eras. We demonstrate that the new variant set provides increased power to identify known causal flowering time genes using previously published trait datasets, as well as the potential to track changes in the frequency of functionally distinct alleles across the global distribution of modern maize.