Biology subjects

Jimenez-Lopez, F. J.

Publications and source records attributed to Jimenez-Lopez, F. J..

5 recordsLinked to original sources

bioRxiv2025

Genomic structure, introgression, niche overlap, and morphological variation challenges species delimitation in Thymus sect. Mastichina

Species delimitation remains a major challenge in understanding biodiversity, particularly in recently diverged lineages, where extensive morphological variability complicates taxonomic inference. In this study, we investigate patterns of morphological and ecological variation within Thymus sect. Mastichina, a Mediterranean lineage that includes the endangered species T. albicans. Previous genomic analyses revealed clear differentiation between two major groups corresponding to ploidy levels, as well as additional genetic structure among diploid lineages. Here, we integrate this genomic framework with detailed analyses of floral morphology and ecological niches to assess the correspondence between phenotypic, ecological, and genetic variation. Our results reveal substantial overlap among genetic lineages at both morphological and ecological levels. Although some differentiation is associated with ploidy level, particularly in floral traits, extensive variability within several lineages obscures clear taxonomic boundaries based on discrete morphological characters. By contrast, some diploid lineages (notably the Cadiz and Algarve groups) show lower morphological variability but still both overlap in morphology and ecological niche. We morphologically characterized a recently discovered diploid lineage (Hercynian) that appears to be cryptic with the tetraploid T. mastichina. Patterns of admixture involving this Hercynian lineage, especially with the diploid Donana group, contribute to pronounced phenotypic overlap, whereas no significant effect of tetraploid introgression on diploid morphology was detected. Ecological niche analyses indicate that niche differentiation is primarily associated with ploidy level rather than among diploid lineages, except for the Hercynian group. Overall, our results demonstrate a marked discordance between phenotypic variation and genetic structure, supporting the interpretation of Thymus sect. Mastichina as a complex of cryptic evolutionary lineages. These findings highlight the limitations of morphology-based taxonomy and emphasize the need for an integrative framework incorporating genome size, genomic information, and geographic distribution for species delimitation.

plant biology↗

bioRxiv2024

Evidence of flowering time advance in blue lupin (Lupinus angustifolius) in the last decades revealed by herbarium data and citizen science databases

Rapid adaptation to climate change in plants manifests through genetic modifications, epigenetic changes, or species-microbiome interactions, with short-living species having a greater potential for adaptation. The integration of historical collection data with modern databases improves our ability to study plant phenology and distribution shifts in response to global change. This study evaluates changes in the flowering phenology and vernalization requirements of Lupinus angustifolius populations across the Iberian Peninsula, assessing the effectiveness of diverse data sources. Using herbarium specimens and field photographs, we compiled flowering data and estimated flowering peaks. Thermal time and vernalization requirements were estimated using recorded flowering stages and high-resolution climate data. Analyses revealed a progressive advancement in L. angustifolius flowering in the last 60 years. Latitude and elevation emerged as significant influencing factors, with greater shifts observed at lower latitudes and elevations. Notably, plants now flower with fewer vernalization days, and higher thermal time, particularly at lower elevations. The adaptive responses of plants to global change are intricate and dynamic. Phenological advancement in flowering appears to be a key strategy for coping with environmental alterations, facilitating survival and reproduction through the interplay of genotype, phenotype, and environment, as well as existing genetic diversity. In this context, historical records and long-term monitoring prove invaluable for assessing the efficacy and pace of these adaptive processes. To improve our understanding of plant adaptation in the context of climate change, it is essential to synthesize diverse data sources and maintain ongoing collection efforts.

evolutionary biology↗

bioRxiv2023

Can a flower color ancestral polymorphism transcend speciation?

Polymorphisms are common in nature, but they are rarely shared among closely related species. They could originate through convergence, ancestral polymorphism, or introgression. Although shared neutral genomic variation is commonplace, very few examples of shared functional traits exist. The blue-orange petal color polymorphisms in two closely related species, Lysimachia monelli and L. arvensis were investigated with UV-vis reflectance spectra, flavonoid biochemistry, and transcriptome comparisons followed by climate niche analysis. The similarities in reflectance spectra, biochemistry, and transcriptomes suggest a single shift from blue-to-orange shared by both lineages is possible. Transcriptome comparisons reveal two orange-specific genes are directly involved in both blue-orange color polymorphisms: DFR-2 specificity redirects flux from the malvidin to the pelargonidin while BZ1-2 stabilizes the pelargonidin with glucose, producing the orange pelargonidin 3-glucoside. The climate niches for each color morph are the same between the two species for three temperature characteristics but differ for four precipitation variables. We suggest that this persistent flower color polymorphism may represent an ancestrally polymorphic trait that has transcended speciation with some unique ecological effects.

evolutionary biology↗

bioRxiv2021

Molecular approaches reveal speciation between red and blue flowered plants in the Mediterranean Lysimachia arvensis and Lysimachia monelli (Primulaceae)

Flower colour constitutes a pivotal evolutionary force in speciation. The Mediterranean Lysimachia arvensis and L. monelli are morphologically variable species having both blue or red flowered plants. Previous studies suggested that L. arvensis plants differing in colour are diverging lineages, but this variation has not been considered in a phylogenetic context. We reconstruct the phylogenetic signal and the ancestral states of flower colour of Mediterranean Lysimachia species by using nuclear (ITS) and three plastid markers. Blue and red specimens are nested in two independent clades in the ITS tree, thus supporting that L. arvensis and L. monelli are polyphyletic, whereas low phylogenetic resolution was found in plastid markers. Blue-flowered L. arvensis is reconstructed sister to L. talaverae in a monophyletic clade sister to the remaining Lysimachia. Red-flowered L. arvensis is reconstructed sister to red-flowered L. monelli in a monophyletic clade sister to blue-flowered L. monelli and L. foemina. Our results suggest that colour lineages in L. arvensis and L. monelli constitute different species, but flower colour did not promote the separation of these lineages. We propose a new name for blue-flowered L. arvensis (L. loeflingii) and a new combination for red-flowered L. monelli (L. collina).

molecular biology↗

bioRxiv2019

Selfing Maintains Flower Colour Polymorphism In L. arvensis Despite High Inbreeding Depression

Flower colour polymorphism (FCP) is frequently associated with differences in pollinator attraction. FCP maintenance is intriguing, as positive directional selection by pollinators should result in the loss of polymorphism. Autonomous selfing could confer reproductive assurance when pollen is limited, and could be a mechanism for maintaining polymorphism unless inbreeding depression is high. We study the role of selfing in maintaining FCP in Lysimachia arvensis, a species with blue and red morphs co-occurring in Mediterranean populations, where pollinators negatively select for the red morph. We experimentally assessed inbreeding depression in both morphs in two Mediterranean populations and genetic diversity was studied via AFLP and SSR microsatellites in 20 populations. Between-morph genetic differentiation was high and the red morph had a lower genetic diversity, mainly in the Mediterranean. Results also show strong phenological differences between selfed and outcrossed progeny, and a high ID of the red morph. The low genetic diversity of the red morph is in concordance with a reproductive system based predominantly on selfing. However, ID suggests a limited capacity for red morph recruitment, according to its low frequency in polymorphic populations. Genetic differentiation between morphs indicates a low gene flow between them, opening the possibility of reproductive isolation and speciation in Lysimachia arvensis.

evolutionary biology↗