Biology subjects

Mohn, R.

Publications and source records attributed to Mohn, R..

3 recordsLinked to original sources

bioRxiv2025

Origin of subgenomes in the circumboreal allopolyploid carnivorous plant Drosera anglica (Droseraceae)

Premise of StudyThe parentage of a widespread member of the carnivorous sundew genus Drosera, the allopolyploid Drosera anglica, remains uncertain despite over 100 years of morphological, cytological, and, more recently, molecular study. MethodsUsing transcriptomic and genomic data from 12 species Drosera sect. Drosera including four D. anglica populations and a disjunct Idaho population of D. intermedia, we assembled genes in HybPiper and phased sequences in HybPhaser. We estimated heterozygosity and generated flow cytometry data to assess ploidy levels. We estimated species relationships with phylogenetic and pairwise genetic distance methods. Additionally, we assembled rbcL and ITS reads to compare to previous data. Key ResultsSequences from phased subgenomes highly supported D. anglica as sister to D. rotundifolia and D. linearis, differing from previous analyses based on chromosome pairing and Sanger sequencing with limited taxon sampling. Both ITS and rbcL sequences of D. anglica were the most similar to D. linearis. Drosera anglica is intermediate between both parents in leaf shape and microhabitat; however, across D. sect. Drosera, neither leaf shape nor biogeographic distribution were reliable indicators of phylogenetic relationships. Despite a range-wide sampling, we did not find evidence for multiple origins of D. anglica. Additionally, we confirmed that the Idaho population previously identified as D. intermedia is D. anglica. ConclusionsDrosera anglica arose from allopolyploidy between D. linearis (the chloroplast donor) and D. rotundifolia. Our study demonstrates the importance of taxon sampling and careful examining complex phylogenomic data, and presents an exemplar of analyzing allopolyploid relationships in plant lineages.

evolutionary biology↗

bioRxiv2024

Genetically based variation in fitness and carbon assimilation among bur oak populations

Ongoing climate change will negatively impact tree populations unless they are able to acclimate to the changes in their local environment. Effective planning for climate adaptation management requires an understanding of the current state of local adaptation and physiological performance to assess whether populations are at risk of local extinction, to determine if seed movement is appropriate, and to select appropriate seed sources if intervention is needed. We established a new reciprocal transplant experiment (ACE, Adaptation to Climate and Environment) across a latitudinal gradient in North America to examine the impacts of warming on three bur oak (Quercus macrocarpa) populations across much of the species range. We established common gardens in Minnesota, Illinois, and Oklahoma with seedlings grown from seeds collected within 50 km of each of those locations from a total of sixty maternal families. We aimed to 1) assess local adaptation in each of the populations using survival and size as fitness metrics, and 2) evaluate physiological responses to different environments along the latitudinal gradient. We found that northern populations are maladapted to hotter climates as evidenced by their low survival, growth, and photosynthetic rates in the warmest common garden. The southernmost population had the highest survival rate, growth rate, and fitness of the three populations in the southernmost garden, providing evidence for local adaptation to the warmest site. However, conditions in the middle garden resulted in the highest fitness and best physiological performance for all populations. Growth and survival were correlated in the middle garden but were decoupled in the northern and southern gardens. This decoupling is likely due to stress associated with more extreme climates at the ends of the gradient that led to greater resource allocation to survival than to growth. Our results suggest that southern seed sources may perform well in warmer conditions in the north brought on by climate change, which has important implications for managers assisting broadly ranged tree species in adapting to climate change.

ecology↗

bioRxiv2017

Persistent homology demarcates a leaf morphospace

Current morphometric methods that comprehensively measure shape cannot compare the disparate leaf shapes found in seed plants and are sensitive to processing artifacts. We explore the use of persistent homology, a topological method applied across the scales of a function, to overcome these limitations. The described method isolates subsets of shape features and measures the spatial relationship of neighboring pixel densities in a shape. We apply the method to the analysis of 182,707 leaves, both published and unpublished, representing 141 plant families collected from 75 sites throughout the world. By measuring leaves from throughout the seed plants using persistent homology, a defined morphospace comparing all leaves is demarcated. Clear differences in shape between major phylogenetic groups are detected and estimates of leaf shape diversity within plant families are made. This approach does not only predict plant family, but also the collection site, confirming phylogenetically invariant morphological features that characterize leaves from specific locations. The application of a persistent homology method to measure leaf shape allows for a unified morphometric framework to measure plant form, including shape and branching architectures.

plant biology↗