Biology subjects

Baczynski, J.

Publications and source records attributed to Baczynski, J..

3 recordsLinked to original sources

bioRxiv2025

Gene duplication dynamics and regulatory evolution shape the diversification of Asteraceae

The flowering plant order Asterales exhibits a striking disparity in species richness, with >30,000 species in Asteraceae compared to <50 in its sister family Calyceraceae. To investigate the genomic basis of this imbalance, we assembled three new chromosome-level genomes, including the first for Calyceraceae, and re-annotated five additional genomes. Comparative analyses revealed exceptionally high repeat content in both Asteraceae and Calyceraceae, pervasive chromosomal rearrangements, and evidence for shared and lineage-specific WGDs. In Asteraceae, tandem and dispersed duplications disproportionately drove expansions of gene families linked to secondary metabolism and stress response, while segmental duplicates bore signatures of adaptive selection for the regulation of biosynthetic and metabolic processes. Selective pressures on flowering time regulators suggest an evolved balance between regulatory flexibility and developmental constraint in floral diversification. These patterns reveal that, beyond ancient polyploidy, small-scale duplications and selective fine-tuning of regulatory networks underpinned the ecological versatility in Asteraceae, fueling its extraordinary diversification.

genomics↗

bioRxiv2025

Floral innovation through modifications in stem cell peptide signaling.

Understanding how evolution shapes genetic networks to create new developmental forms is a central question in biology. Asteraceae (sunflower family) comprise 10% of flowering plants and have capitula, a novel flowering shoot (inflorescence) that mimics a single flower (1, 2). During capitulum development, shoot stem cells undergo prolonged proliferation relative to other species (3, 4). Here we show that capitulum evolution paralleled decreases in CLAVATA3 peptide (CLV3p) signaling, a conserved repressor of stem cell proliferation. Asteraceae CLV3p displays reduced receptor binding and downstream transcriptional outputs. Reversion of CLV3 to a more active form impairs Asteraceae stem cell regulation and capitulum development. Lastly, we trace CLV3 evolution across the Asterales allowing inferences on capitulum evolution. Our findings reveal novel evolutionary mechanisms in plant reproduction and suggest approaches for engineering crops.

plant biology↗

bioRxiv2025

Molecular phylogeny of Catenulida (Platyhelminthes) with special focus on their diversity in Poland

Catenulida is a clade of free-living flatworms found abundantly in freshwater habitats across the globe. Despite their ubiquitous distribution, catenulids remain poorly studied; most of the species are known only from the asexual forms that lack distinct, taxonomically useful characters. Accordingly, the studies of catenulid diversity require application of integrative methods that combine morphological and molecular data. Here, we report the survey of catenulid diversity in Central and Western Europe, with a special focus on the species found in Polish freshwaters. We collected and identified 13 distinct morphotypes that were subsequently sequenced for four molecular markers - 18S, 28S, COI and ITS-5.8S. The obtained sequences, together with reference data from other catenulid species, were used to infer the comprehensive phylogeny of the clade. The analysis revealed several well-supported clades within the largest catenulid family, Stenostomidae, highlighting the major challenges in catenulid taxonomy, such as unresolved species complexes of Stenostomum leucops and Stenostomum simplex. By tracing evolution of morphological, developmental and ecological characters on the phylogeny our study provides insight into major character transitions in the key lineages of catenulids.

zoology↗