Biology subjects

Northing, P. C.

Publications and source records attributed to Northing, P. C..

3 recordsLinked to original sources

bioRxiv2026

Near chromosome-level genome assembly for the invasive annual forb Centaurea melitensis

PremiseCentaurea melitensis (Asteraceae) is a problematic invader of grasslands globally, but little is known about its genetic makeup. Here we develop a reference genome to facilitate studies of its invasion history, genetic variation, and evolution. MethodsInbred offspring of a single individual of C. melitensis from its invasion of California, USA were used for flow cytometry to estimate genome size, and for genomic DNA extraction. DNA was sequenced with PacBio HiFi technology (yield = 85.7Gb). The genome was assembled with Hifiasm and annotated with BRAKER3. GENESPACE was used to compare gene order (synteny) with three other species within the subfamily Cichorioideae. ResultsWe estimated a mean genome size of 795.0 Mbp for C. melitensis, and our assembly totaled 696.6 Mbp in 48 contigs (N50 = 55.6 Mbp; BUSCO = 98%), with annotation of 25,157 protein-encoding genes. This included four telomere-to-telomere putative chromosomes, nine additional chromosome arms terminated by telomeric repeats, and a complete chloroplast genome. Synteny varied markedly across the genus and subfamily, suggesting a dynamic history of structural variation in the lineage of C. melitensis. DiscussionWe provide a highly complete and contiguous genome assembly to facilitate the further study of genomic variation in C. melitensis.

genomics↗

bioRxiv2026

Testing fundamental hypotheses of colonization success in the ferns

Background and AimsNon-native species are now ubiquitous members of regional floras. The factors that lead to establishment and dominance of non-native species are continuously debated. Fundamental hypotheses about drivers of invasion success include the role of phylogeny, polyploidy, genome size, and rapid niche evolution. These hypotheses have been tested in the seed plants, but ferns, the second largest group of vascular plants, have rarely been considered in these analyses, despite making up a non-trivial portion of non-native floras. MethodsWe compiled a dataset of global non-native ferns and categorized them along the invasion spectrum using descriptions from the literature and natural history collections. Using this dataset, we assessed I) the taxonomic diversity and phylogenetic clustering of non-native ferns, II) the geographic distribution of fern introductions, testing for shifts in climatic niches, and III) test for the association of invader traits across the invasion continuum, including smaller genome sizes and higher ploidal levels. Key ResultsWe generated a dataset that includes 83 taxa; of these, we classified 18 as casual, 35 as naturalized (but not invasive), and 30 as invasive. Using this dataset, we found I) weak or no phylogenetic clustering of non-native ferns, II) some regions are overrepresented as sources and recipients of introductions, III) climatic niches are often conserved between native and introduced ranges, but can differ between introductions, IV) naturalized ferns have smaller genomes, and V) invaders have higher ploidal levels. ConclusionsWe integrated regional floras, occurrence and climate data, phylogeny, and cytology to test fundamental hypotheses regarding the colonization success of ferns. This study provides insights into the ecological, genomic, and phylogenetic features associated with the colonization of new habitats by non-native ferns, a largely overlooked portion of non-native plant taxa.

evolutionary biology↗

bioRxiv2024

Chromosome-scale reference genome of Pectocarya recurvata, a species with one of the smallest genome sizes in Boraginaceae

PremisePectocarya recurvata (Boraginaceae), a native species of the Sonoran Desert, has served as an important model system for a suite of ecological and evolutionary studies. Despite its relevance as an eco-evolutionary model, no reference genome assemblies in the Cynoglossoideae subfamily have been published. MethodsUsing PacBio HiFi sequencing, we assembled a reference genome for P. recurvata and annotated coding regions with full-length transcripts from an Iso-Seq transcriptome library. We assessed genome completeness with BUSCO and used flow cytometry and K-mer analysis to estimate the genome size of P. recurvata. ResultsThe chromosome-scale reference genome assembly for P. recurvata was 216.0 Mbp long with a contig N50 of 12.1 Mbp. Our assembly included 12 primary contigs bounded by telomeres at all ends but one, consistent with the 12 chromosomes documented for the species. The chromosomes covered 158.3 Mbp and contained 30,655 predicted genes. Our measured haploid genome size from the same population was 386.5 Mbp, among the smallest for Boraginaceae. Genomic analyses suggested that this may reflect a recent autotetraploid, such that predicted diploid genome size would be even smaller and similar to the assembly size. DiscussionThe P. recurvata assembly and annotation provide a high-quality genomic resource in a sparsely represented area of the Angiosperm phylogeny. Our new genome will enable future ecophysiology, biogeography, and phylogenetics research.

genomics↗