Christian Lexer

Christian Lexer
University of Vienna | UniWien · Department of Botany and Biodiversity Research

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290
Publications
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Publications

Publications (290)
Article
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Knowledge of the patterns of variation in plant mating systems and fitness, in the context of conservation biology, is essential for understanding microscale differences and their probable causes. The aim of this study was to assess the patterns and determinants of spatiotemporal variation in fertility, mating systems, and gene flow in the epiphyti...
Article
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Target capture has emerged as an important tool for phylogenetics and population genetics in non-model taxa. Whereas developing taxon-specific capture probes requires sustained efforts, available universal kits may have a lower power to reconstruct relationships at shallow phylogenetic scales and within rapidly radiating clades. We present here a n...
Preprint
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Investigating genome-wide variation patterns along a speciation continuum is of central importance to understand the evolutionary processes contributing to lineage diversification. To identify which forces have shaped the genomic landscapes in Populus, we resequenced 201 whole-genomes from eight closely related species, with pairs of species at dif...
Article
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Understanding local adaptation has become a key research area given the ongoing climate challenge and the concomitant requirement to conserve genetic resources. Perennial plants, such as forest trees, are good models to study local adaptation given their wide geographic distribution, largely outcrossing mating systems and demographic histories. We...
Article
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Background and Aims: Quantifying genetic variation is fundamental to understand a species’ demographic trajectory and its ability to adapt to future changes. In comparison with diploids, however, genetic variation and factors fostering genetic divergence remain poorly studied in polyploids due to analytical challenges. Here, by employing a ploidy-a...
Preprint
Full-text available
Target capture emerged as an important tool for phylogenetics and population genetics in non-model taxa. Whereas developing taxon-specific capture probes requires sustained efforts, available universal kits may have a lower power to reconstruct relationships at shallow phylogenetic scales and within rapidly radiating clades. We present here a newly...
Article
Full-text available
The tropics hold at least an order of magnitude greater plant diversity than the temperate zone, yet the reasons for this difference are still subject to debate. Much of tropical plant diversity is in highly speciose genera and understanding the drivers of such high species richness will help solve the tropical diversity enigma. Hybridization has r...
Preprint
Full-text available
Understanding local adaptation in plants from a genomic perspective has become a key research area given the ongoing climate challenge and the concomitant requirement to conserve genetic resources. Perennial plants, such as forest trees, are good models to study local adaptation given their wide geographic distribution, largely outcrossing mating s...
Article
Full-text available
An amendment to this paper has been published and can be accessed via the original article.
Article
Many recent studies have addressed the mechanisms operating during the early stages of speciation, but surprisingly few studies have tested theoretical predictions on the evolution of strong reproductive isolation (RI). To help address this gap, we first undertook a quantitative review of the hybrid zone literature for flowering plants in relation...
Article
The adaptive radiation of Bromeliaceae (pineapple family) is one of the most diverse among Neotropical flowering plants. Diversification in this group was facilitated by shifts in several adaptive traits or “key innovations” including the transition from C3 to CAM photosynthesis associated with xeric (heat/drought) adaptation. We used phylogenomic...
Article
Information on the genetic architecture of phenotypic traits is helpful for constructing and testing models of the eco‐evolutionary dynamics of natural populations. For plant groups with long life cycles there is a lack of line cross experiments that can unravel the genetic architecture of loci underlying quantitative traits. To fill this gap, we p...
Article
Vriesea is the second largest genus in Tillandsioideae, the most diverse subfamily of Bromeliaceae. Although recent studies focusing on Tillandsioideae have improved the systematics of Vriesea, no consensus has been reached regarding the circumscription of the genus. Here, we present a phylogenetic analysis of core Tillandsioideae using the nuclear...
Article
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Background The angiosperm family Bromeliaceae comprises over 3.500 species characterized by exceptionally high morphological and ecological diversity, but a very low genetic variation. In many genera, plants are vegetatively very similar which makes determination of non flowering bromeliads difficult. This is particularly problematic with living co...
Article
In non‐model organisms, evolutionary questions are frequently addressed using reduced representation sequencing techniques due to their low cost, ease of use, and because they do not require genomic resources such as a reference genome. However, evidence is accumulating that such techniques may be affected by specific biases, questioning the accura...
Preprint
Full-text available
In non-model organisms, evolutionary questions are frequently addressed using reduced representation sequencing techniques due to their low cost, ease of use, and because they do not require genomic resources such as a reference genome. However, evidence is accumulating that such techniques may be affected by specific biases, questioning the accura...
Article
Vriesea is the second largest genus in Tillandsioideae, the most diverse subfamily of Bromeliaceae. Although recent studies focusing on Tillandsioideae have improved the systematics of Vriesea, no consensus has been reached regarding the circumscription of the genus. Here, we present a phylogenetic analysis of core Tillandsioideae using the nuclear...
Article
Full-text available
Domestication of clonally propagated crops such as pineapple from South America was hypothesized to be a ‘one-step operation’. We sequenced the genome of Ananas comosus var. bracteatus CB5 and assembled 513 Mb into 25 chromosomes with 29,412 genes. Comparison of the genomes of CB5, F153 and MD2 elucidated the genomic basis of fiber production, colo...
Article
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The tribe Geonomateae is a widely distributed group of 103 species of Neotropical palms which contains six ecologically important understory or subcanopy genera. Although it has been the focus of many studies, our understanding of the evolutionary history of this group, and in particular of the taxonomically complex genus Geonoma, is far from compl...
Article
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The genomic architecture of functionally important traits is key to understanding the maintenance of reproductive barriers and trait differences when divergent populations or species hybridize. We conducted a Genome‐Wide Association Study (GWAS) to study trait architecture in natural hybrids of two ecologically divergent Populus species. ●We genoty...
Preprint
Full-text available
The genomic architecture of functionally important traits is key to understanding the maintenance of reproductive barriers and trait differences when divergent populations or species hybridize. We conducted a Genome-Wide Association Study (GWAS) to study trait architecture in natural hybrids of two ecologically divergent Populus species. We genotyp...
Preprint
Full-text available
The adaptive radiation of Bromeliaceae (pineapple family) is one of the most diverse among Neotropical flowering plants. Diversification in this group was facilitated by several key innovations including the transition from C3 to CAM photosynthesis. We used a phylogenomic approach complemented by differential gene expression (RNA-seq) and targeted...
Article
Full-text available
Understanding the genetics of biological diversification across micro‐ and macro‐evolutionary time scales is a vibrant field of research for molecular ecologists as rapid advances in sequencing technologies promise to overcome former limitations. In palms, an emblematic, economically and ecologically important plant family with high diversity in th...
Article
Introgression can introduce novel genetic variation at a faster rate than mutation alone, and result in adaptive introgression when adaptive alleles are maintained in the recipient genome over time by natural selection. A previous study from our group demonstrated adaptive introgression from Populus balsamifera into P. trichocarpa in a target genom...
Article
Introgression is emerging as an important source of novel genetic variation, alongside standing variation and mutation. It is adaptive when such introgressed alleles are maintained by natural selection. Recently, there has been an explosion in the number of studies on adaptive introgression. In this review, we take a plant perspective centred on fo...
Article
Introgression can be an important source of adaptive phenotypes, although conversely it can have deleterious effects. Evidence for adaptive introgression is accumulating but information on the genetic architecture of introgressed traits lags behind. Here we determine trait architecture in Populus trichocarpa under introgression from P. balsamifera...
Article
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Nectarless flowers that deceive pollinators offer an opportunity to study asymmetric plant-insect interactions. Orchids are a widely used model for studying these interactions because they encompass several thousand species adopting deceptive pollination systems. High levels of intra-specific phenotypic variation have been reported in deceptive orc...
Data
Scanned digital images used for morphological measurements Scanned digital images of (A) O. pauciflora and (B) O. mascula floral parts. From left to right: spur, labellum.
Data
Raw data Morphological measurements and reproductive success of investigated individuals.
Article
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Understanding the drivers and limits of species radiations is a crucial goal of evolutionary genetics and molecular ecology, yet research on this topic has been hampered by the notorious difficulty of connecting micro- and macro-evolutionary approaches to studying the drivers of diversification. To chart the current research gaps, opportunities, an...
Article
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Forest trees are an unparalleled group of organisms in their combined ecological, economic, and societal importance. With widespread distributions, predominantly random mating systems, and large population sizes, most tree species harbor extensive genetic variation both within and among populations. At the same time, demographic processes associate...
Article
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Asexual reproduction is a common and fundamental mode of reproduction in plants. Although persistence in adverse conditions underlies most known cases of clonal dominance, proximal genetic drivers remain unclear, in particular for populations dominated by a few large clones. In this paper, we studied a clonal population of the riparian tree Populus...
Article
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1. While fire induced changes in biodiversity are well documented, less is known about how fire impacts life history variation and diversity of functional traits that represent distinct strategies for persistence in fire-driven ecosystems. One example is the dichotomy in which ‘resprouter’ species usually survive fires to produce new growth, while...
Article
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Inselberg-adapted species of bromeliads (Bromeliaceae) have been suggested as model systems for understanding the evolutionary genetics of species complexes and radiations in terrestrial, island-like environments. Bromeliads are particularly suitable for addressing the potential roles of interspecific gene exchange during plant speciation and radia...
Article
Speciation often involves repeated episodes of genetic contact between divergent populations before reproductive isolation (RI) is complete. Whole genome sequencing (WGS) holds great promise for unravelling the genomic bases of speciation. We have studied two ecologically divergent, hybridizing species of the 'model tree' genus Populus (poplars, as...
Article
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Alpine ecosystems are seriously threatened by climate change. One of the key mechanisms by which plants can adapt to changing environmental conditions is through evolutionary change. However, we still know little about the evolutionary potential in wild populations of long-lived alpine plants. Here, we investigated heritabilities of phenological tr...
Article
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Natural hybrid zones have proven to be precious tools for understanding the origin and maintenance of reproductive isolation (RI) and therefore species. Most available genomic studies of hybrid zones using whole or partial genome resequencing approaches have focused on comparisons of the parental source populations involved in genome admixture, rat...
Article
Natural hybrid zones in forest trees provide systems to study the transfer of adaptive genetic variation by introgression. Previous landscape genomic studies in Populus trichocarpa, a keystone tree species, indicated genomic footprints of admixture with its sister species P. balsamifera and identified candidate genes for local adaptation. Here, we...
Article
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Resistance genes (R-genes) are essential for long-lived organisms such as forest trees, which are exposed to diverse herbivores and pathogens. In short-lived model species, R-genes have been shown to be involved in species isolation. Here, we studied more than 400 trees from two natural hybrid zones of the European Populus species Populus alba and...
Article
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The mechanisms responsible for the origin, maintenance and evolution of plant secondary metabolite diversity remain largely unknown. Decades of phenotypic studies suggest hybrid-ization as a key player in generating chemical diversity in plants. Knowledge of the genetic architecture and selective constraints of phytochemical traits is key to unders...
Article
Full-text available
• The mating system is an important component of the complex set of reproductive isolation barriers causing plant speciation. However, empirical evidence showing that the mating system may promote reproductive isolation in co-occurring species is limited. The mechanisms by which the mating system can act as a reproductive isolation barrier are also...
Article
Full-text available
Climate change is altering spring snowmelt patterns in alpine and arctic ecosystems, and these changes may alter plant phenology, growth and reproduction. To predict how alpine plants respond to shifts in snowmelt timing, we need to understand trait plasticity, its effects on growth and reproduction, and the degree to which plants experience a home...
Article
Studying the divergence continuum in plants is relevant to fundamental and applied biology because of the potential to reveal functionally important genetic variation. In this context, whole-genome sequencing (WGS) provides the necessary rigour for uncovering footprints of selection. We resequenced populations of two divergent phylogeographic linea...