Biology subjects

Doyle, J. J.

Publications and source records attributed to Doyle, J. J..

9 recordsLinked to original sources

bioRxiv2026

Repurposing the HMG-CoA Reductase Inhibitor Atorvastatin for SRD5A3-CDG

SRD5A3-CDG is a rare autosomal recessive congenital disorder of glycosylation characterized by multisystemic dysfunction, including neurological, psychomotor, cognitive, and visual impairments. Approximately 60 cases have been reported, with treatment limited to symptomatic management. SRD5A3 encodes a polyprenal reductase enzyme essential for synthesizing dolichol, a lipid carrier of the oligosaccharide precursor in N-glycosylation. To address the lack of effective treatments and disease models suitable for high-throughput screening, we developed the first C. elegans model of SRD5A3-CDG, harboring the homozygous W19X nonsense mutation commonly observed in patients. This model recapitulates disease-relevant phenotypes, including developmental delays, neurological dysfunction, and mevalonate pathway dysregulation. Using this model, we conducted a high-throughput motility-based drug repurposing screen and identified atorvastatin, an FDA-approved HMG-CoA reductase inhibitor, as a repurposing candidate. Atorvastatin rescued disease-relevant phenotypes in the worm model and restored polyprenol-to-dolichol ratios in patient fibroblasts. These findings highlight atorvastatin as a promising drug repurposing candidate for SRD5A3-CDG.

cell biology↗

bioRxiv2024

The topography of gene tree topology space in a plant genus with a legacy of recent polyploidy and introgression

The eukaryotic genome has been described as a collection of different histories; for any set of taxa one of these histories is the record of cladogenic events that together comprise the species tree. Among the other histories expected to occur are those attributable to deep coalescence/lineage sorting; to biological causes such as introgression and horizontal transfer; or to pseudo-orthology, long branch attraction, and other technical issues. Gene tree topology space is the portion of tree space occupied by the gene trees reconstructed for a particular dataset of sampled genetic loci. Because coalescent theory predicts that the species tree topology will generally be the most frequent among gene trees, a reasonable expectation is that there will be a peak in gene tree topology space at the species tree topology, with secondary peaks present due to trees tracking other histories. Gene tree topology space in the small ([~]30 species, including the cultivated soybean) legume genus, Glycine should not only have signals from the species tree and from lineage sorting, but also from a likely introgression event that created incongruence between the plastid and nuclear genomes. Additionally, Glycine is the product of a relatively recent (<13 million years) whole genome duplication, raising the possibility of pseudo-orthology. We explored this space using a set of 2389 nuclear genes and representative accessions from a 570-taxon concatenation tree, reconstructing gene trees for all nuclear loci and from complete plastid genomes and partial mitochondrial genomes. Species trees (ASTRAL) and maximum likelihood (ML) concatenation trees were congruent for a 61-taxon dataset but were incongruent with organellar genome trees. Gene tree topology space was flat: No topology was represented by more than one gene tree. This was also true for a reduced dataset of 27 taxa; only when the dataset was reduced to six ingroup taxa were multiple gene trees having the species tree topology observed, along with a topology congruent with the chloroplast genome topology, presumably representing nuclear loci introgressed along with the plastome. Clustering failed to identify any regional differentiation of gene tree topology space populated by loci with similar topologies. Pseudo-orthology did not contribute meaningfully to incongruence, in agreement with recent modeling work that minimizes concerns about this phenomenon. Clearly, different genes have different historical signals, but these signals are complex and exist at the level of clades within trees rather than as entire gene trees.

evolutionary biology↗

bioRxiv2024

nQuack: An R package for predicting ploidal level from sequence data using site-based heterozygosity

PremiseTraditional methods of ploidal level estimation are tedious; leveraging sequence data for cytotype estimation is an ideal alternative. Multiple statistical approaches to leverage DNA sequence data for ploidy prediction based on site-based heterozygosity have been developed. However, these approaches may require high-coverage sequence data, use improper probability distributions, or have additional statistical shortcomings that limit inference abilities. We introduce nQuack, an open-source R package, that addresses the main shortcomings of current methods. Methods and ResultsnQuack performs model selection for improved ploidy predictions. Here, we implement expected maximization algorithms with normal, beta, and beta-binomial distributions. Using extensive computer simulations that account for variability in sequencing depth, as well as real data sets, we demonstrate the utility and limitations of nQuack. ConclusionInferring ploidal level based on site-based heterozygosity alone is discouraged due to the low accuracy of pattern-based inference.

bioinformatics↗

bioRxiv2023

Comparative phylogenomic analyses of SNP versus full locus datasets: insights and recommendations for researchers

PremiseIn phylogenomic analyses, no consensus exists on whether using single nucleotide polymorphisms (SNPs) or including flanking regions (full locus) is best, nor how strictly missing data should be filtered. Moreover, empirical evidence on whether SNP-only trees are suitable for downstream phylogenetic comparative methods such as divergence time estimation and ancestral state reconstructions is lacking. MethodsUsing GBS data from 22 taxa of Glycine, we addressed the effects of SNP vs. locus usage and filtering stringency on phylogenomic inference and phylogenetic comparative methods. We compared branch length, node support, and divergence time estimation across eight datasets with varying amounts of missing data and total size. ResultsOur results reveal five aspects of phylogenomic data usage: 1. tree topology is largely congruent regardless of data type or filtering parameters; 2. filtering missing data too strictly reduces the confidence in some relationships; 3. absolute branch lengths vary by two orders of magnitude between datasets; 4. data type and branch length variation have little effect on divergence time estimation; 5. phylograms significantly alter the estimation of ancestral states. DiscussionWhen conducting phylogenomic analyses we recommend not to filter datasets too strictly to minimize the risk of misleading topologies, low support, and inaccurate divergence times.

evolutionary biology↗

bioRxiv2023

Comparative Phylogenomics and Phylotranscriptomics Provide Insights into the Genetic Complexity of Nitrogen Fixing Root Nodule Symbiosis

Plant root nodule symbiosis (RNS) with mutualistic nitrogen-fixing bacteria is restricted to a single clade of angiosperms, the Nitrogen-Fixing Nodulation Clade (NFNC), and is best understood in the legume family. It is widely accepted that nodulation originated through the assembly of modules recruited from existing functions, such as mycorrhizal symbiosis, polar growth, and lateral root development. Because nodulating species are scattered within the NFNC, the number of times nodulation has evolved or has been lost has been a matter of considerable speculation. This interesting evolutionary question has practical implications concerning the ease with which nodulation might be engineered in non-nodulating crop plants. Nodulating species share many commonalities, due either to divergence from a common ancestor over 100 million years ago or to convergence or deep homology following independent origins over that same time period. In either case, comparative analyses of diverse nodulation syndromes can provide insights into constraints on nodulation--what must be acquired or cannot be lost for a functional symbiosis--and what the latitude is for variation in the symbiosis. However, much remains to be learned about nodulation, especially outside of legumes. Here we present new information across the spectrum of nodulating groups. We find no evidence for convergence at the level of amino acid residues or gene family expansion across the NFNC. Our phylogenomic analyses further emphasize the uniqueness of the transcription factor, NIN, as a master regulator of nodulation, and identify key mutations affecting its function across the NFNC. We find that nodulation genes are over-represented among orthologous gene groups (OGs) present in the NFNC common ancestor, but that lineage-specific OGs play major roles in nodulation. We identified over 900,000 conserved noncoding elements (CNEs), of which over 300,000 were unique to NFNC species. A significant proportion of these are associated with nodulation-related genes and thus are candidates for transcriptional regulators.

evolutionary biology↗

bioRxiv2021

Epigenetic modulation in the pathogenesis and treatment of inherited aortic aneurysm conditions

Shprintzen-Goldberg syndrome (SGS) is a rare systemic connective tissue disorder characterized by craniofacial, skeletal, neurodevelopmental, cutaneous, and cardiovascular manifestations, including aortic root aneurysm. It has significant phenotypic overlap with both Marfan syndrome (MFS) and Loeys-Dietz syndrome (LDS). We previously reported that SGS is caused by heterozygous mutations in the Sloan-Kettering Institute proto-oncogene (SKI), which encodes a potent suppressor of transforming growth factor beta (TGF{beta}) target gene expression. Herein, we show that mouse lines harboring orthologous amino acid substitutions in Ski recapitulate multiple human SGS phenotypic manifestations, including skin collagen deposition, skeletal kyphosis, behavioral hypoactivity, and aortic root aneurysm. Furthermore, aortic root aneurysm in SGS mice is associated with both increased acetylation of histone H3 at lysine-27 (H3K27) and TGF{beta} target gene expression, all of which can be ameliorated by pharmacological CBP/P300 inhibition in vivo; similar findings were seen in cultured dermal fibroblast from SGS patients. Aortic root growth is also abrogated in a mouse model of MFS by selective CBP/P300 inhibition in association with blunted expression of TGF{beta} target genes. These data document excessive H3K27 acetylation and hence TGF{beta} target gene expression in the pathogenesis of inherited presentations of aortic root aneurysm and the therapeutic potential of pharmacological epigenetic modulation.

genetics↗

bioRxiv2020

Expression partitioning of duplicate genes at single cell resolution in Arabidopsis roots

Gene duplication is a key evolutionary phenomenon, prevalent in all organisms but particularly so in plants, where whole genome duplication (WGD; polyploidy) is a major force in genome evolution. Much effort has been expended in attempting to understand the evolution of duplicate genes, addressing such questions as why some paralogue pairs rapidly return to single copy status whereas, in other pairs, paralogues are retained and may (or may not) diverge in expression pattern or function. The effect of a gene--its site of expression and thus the initial locus of its function--occurs at the level of a cell comprising a single cell type at a given state of the cells development. Thus, it is critical to understand the expression of duplicated gene pairs at a cellular level of resolution. Using Arabidopsis thaliana root single cell transcriptomic data we identify 36 cell clusters, each representing a cell type at a particular developmental state, and analyze expression patterns of over 11,000 duplicate gene pairs produced by three cycles of polyploidy as well as by various types of single gene duplication mechanisms. We categorize paralogue pairs by their patterns of expression, identifying pairs showing strongly biased paralogue/homoeologue expression in different cell clusters. Notably, the precision of cell-level expression data permits the identification of pairs showing alternate bias, with each paralogue comprising 90% or greater of the pairs expression in different cell clusters, consistent with subfunctionalization at the cell type or cell state level, and, in some cases, at the level of individual cells. We identify a set of over 7,000 genes whose expression in all 36 cell clusters suggests that the single copy ancestor of each was also expressed in all root cells. With this cell-level expression information we hypothesize that there have been major shifts in expression for the majority of duplicated genes, to different degrees depending, as expected, on gene function and duplication type, but also on the particular cell type and state.

plant biology↗

bioRxiv2019

Gene balance predicts transcriptional responses immediately following ploidy change in Arabidopsis thaliana

The Gene Balance Hypothesis postulates that there is selection on gene copy number (gene dosage) to preserve stoichiometric balance among interacting proteins. This presupposes that gene product abundance is governed by gene dosage, and that the way in which gene product abundance is governed by gene dosage is consistent for all genes in a dosage-sensitive network or complex. Gene dosage responses, however, have rarely been quantified and the available data suggest that they are highly variable. We sequenced the transcriptomes of two synthetic autopolyploid accessions of Arabidopsis thaliana and their diploid progenitors, as well as one natural tetraploid and its synthetic diploid produced via haploid induction, to estimate transcriptome size and gene dosage responses immediately following ploidy change. We demonstrate that overall transcriptome size does not exhibit a simple doubling in response to genome doubling, and that individual gene dosage responses are highly variable in all three accessions, indicating that expression is not strictly coupled with gene dosage. Nonetheless, putatively dosage-sensitive gene groups (GO terms, metabolic networks, gene families, and predicted interacting protein pairs) exhibit both smaller and more coordinated dosage responses than do putatively dosage-insensitive gene groups, suggesting that constraints on dosage balance operate immediately following whole genome duplication. This supports the hypothesis that duplicate gene retention patterns are shaped by selection to preserve dosage balance.

plant biology↗

bioRxiv2017

Karyotype stability and unbiased fractionation in the paleo-allotetraploid Cucurbita genomes

The Cucurbita genus contains several economically important species in the Cucurbitaceae family. Interspecific hybrids between C. maxima and C. moschata are widely used as rootstocks for other cucurbit crops. We report high-quality genome sequences of C. maxima and C. moschata and provide evidence supporting an allotetraploidization event in Cucurbita. We are able to partition the genome into two homoeologous subgenomes based on different genetic distances to melon, cucumber and watermelon in the Benincaseae tribe. We estimate that the two diploid progenitors successively diverged from Benincaseae around 31 and 26 million years ago (Mya), and the allotetraploidization happened earlier than 3 Mya, when C. maxima and C. moschata diverged. The subgenomes have largely maintained the chromosome structures of their diploid progenitors. Such long-term karyotype stability after polyploidization is uncommon in plant polyploids. The two subgenomes have retained similar numbers of genes, and neither subgenome is globally dominant in gene expression. Allele-specific expression analysis in the C. maxima x C. moschata interspecific F1 hybrid and the two parents indicates the predominance of trans-regulatory effects underlying expression divergence of the parents, and detects transgressive gene expression changes in the hybrid correlated with heterosis in important agronomic traits. Our study provides insights into plant genome evolution and valuable resources for genetic improvement of cucurbit crops.

genomics↗