Biology subjects

Abeyratne, C. R.

Publications and source records attributed to Abeyratne, C. R..

3 recordsLinked to original sources

bioRxiv2025

Population and adaptation history of 739 Thlaspi arvense natural accessions

Pennycress (Thlaspi arvense) is a promising intermediate oilseed crop, producing oil suitable for conversion to biofuels--including aviation fuels. While domestication efforts are ongoing, a deeper understanding of the genetic architecture of traits is crucial for informing future breeding efforts. Here, we conducted the largest genomic and phenotypic survey of pennycress to date, analyzing 739 accessions collected across four continents. Leveraging whole-genome sequencing and field-collected phenotypes, we characterized the standing genetic variation underlying key agronomic traits and climate resilience. Our findings revealed multiple independent migration events to North America, with substantial genetic admixture. We identified homologs of Arabidopsis thaliana flowering-time genes that contribute to adaptation and demonstrated the agronomic benefits of winter-type pennycress. Furthermore, through multi-season field trials, we identified a genomic region containing a cluster of mTERF genes strongly associated with green canopy coverage, a critical trait for biomass retention and yield stability. These insights provide a genomic roadmap for accelerating pennycress domestication and improving its resilience to climate variability.

genomics↗

bioRxiv2024

Epigenomic manipulation reveals the relationship between locus specific chromatin dynamics and gene expression

Dysregulation of epigenetic processes leads to a plethora of abnormalities including disease states such as cancer. Therapies focused on epigenetic modulation alter gene expression to correct dysfunction, though the mechanisms and perpetuation of these states is unknown. Here, we use integrated epigenomics and three-dimensional chromatin structure-function analyses after acute histone deacetylase inhibitor cancer drug treatment (suberoylanilide hydroxamic acid in lung cancer cells). Treatment induced substantial (13%) genomic rearrangement that rebounds despite persistent gene expression changes and spreading of acetylation. The chromatin functional landscape (accessibility, active transcription modification, and gene expression) is controlled and locus-specific, while chromatin contacts are globally altered resulting in a moderate weakening of topologically associating domains. Chromatin states are more dynamic at transcriptionally active loci while genes with reduced expression are epigenetically stable suggesting chromatin architectural turnover and nucleosome remodeling is locus-specific and underlies the bidirectional expression changes. Thus, local 3D chromatin and genome structural dynamics is integral for loci regulation in response to epigenomic perturbation. The partial persistence of these altered features may have larger implications for efficacy of epigenetic drugs in amelioration of disease states.

cancer biology↗

bioRxiv2022

High resolution mapping reveals hotspots and sex-biased recombination in Populus trichocarpa

Fine-scale meiotic recombination is fundamental to the outcome of natural and artificial selection. Here, dense genetic mapping and haplotype reconstruction were used to estimate recombination for a full factorial Populus trichocarpa cross of seven males and seven females. Genomes of the resulting 49 full-sib families (N=829 offspring) were re-sequenced, and high-fidelity biallelic SNP/INDELs and pedigree information were used to ascertain allelic phase and impute progeny genotypes to recover gametic haplotypes. The fourteen parental genetic maps contained 1820 SNP/INDELs on average that covered 376.7 Mb of physical length across 19 chromosomes. Comparison of parental and progeny haplotypes allowed fine-scale demarcation of cross-over (CO) regions, where 38,846 CO events in 1,658 gametes were observed. CO events were positively associated with gene density and negatively associated with GC content and long terminal repeats. One of the most striking findings was higher rates of COs in males in 8 out of 19 chromosomes. Regions with elevated male CO rates had lower gene density and GC content than windows showing no sex bias. High-resolution analysis identified 67 candidate CO hotspots spread throughout the genome. DNA sequence motifs enriched in these regions showed striking similarity to those of maize, Arabidopsis and wheat. These findings, and recombination estimates, will be useful for ongoing efforts to accelerate domestication of this and other biomass feedstocks, as well as future studies investigating broader questions related to evolutionary history, perennial development, phenology, wood formation, vegetative propagation, and dioecy that cannot be studied using annual plant model systems.

genetics↗