Biology subjects

Woodhouse, M.

Publications and source records attributed to Woodhouse, M..

3 recordsLinked to original sources

bioRxiv2020

Gapless assembly of maize chromosomes using long read technologies

Creating gapless telomere-to-telomere assemblies of complex genomes is one of the ultimate challenges in genomics. We used long read technologies and an optical map based approach to produce a maize genome assembly composed of only 63 contigs. The B73-Ab10 genome includes gapless assemblies of chromosome 3 (236 Mb) and chromosome 9 (162 Mb), multiple highly repetitive centromeres and heterochromatic knobs, and 53 Mb of the Ab10 meiotic drive haplotype.

bioinformatics↗

bioRxiv2019

Effect of Sequence Depth and Length in Long-read Assembly of the Maize Inbred NC358

Recent improvements in the quality and yield of long-read data and scaffolding technology have made it possible to rapidly generate reference-quality assemblies for complex genomes. Still, generating these assemblies is costly, and an assessment of critical sequence depth and read length to obtain high-quality assemblies is important for allocating limited resources. To this end, we have generated eight independent assemblies for the complex genome of the maize inbred line NC358 using PacBio datasets ranging from 20-75x genomic depth and N50 read lengths of 11-21 kb. Assemblies with 30x or less depth and N50 read length of 11 kb were highly fragmented, with even the low-copy genic fraction of the genome showing degradation at 20x depth. Distinct sequence-quality thresholds were observed for complete assembly of genes, transposable elements, and highly repetitive genomic features such as telomeres, heterochromatic knobs and centromeres. This study provides a useful resource allocation reference to the community as long-read technologies continue to mature.

genomics↗

bioRxiv2017

Profiling of accessible chromatin regions across multiple plant species and cell types reveals common gene regulatory principles and new control modules

The transcriptional regulatory structure of plant genomes remains poorly defined relative to animals. It is unclear how many cis-regulatory elements exist, where these elements lie relative to promoters, and how these features are conserved across plant species. We employed the Assay for Transposase-Accessible Chromatin (ATAC-seq) in four plant species (Arabidopsis thaliana, Medicago truncatula, Solanum lycopersicum, and Oryza sativa) to delineate open chromatin regions and transcription factor (TF) binding sites across each genome. Despite 10-fold variation in intergenic space among species, the majority of open chromatin regions lie within 3 kb upstream of a transcription start site in all species. We find a common set of four TFs that appear to regulate conserved gene sets in the root tips of all four species, suggesting that TF-gene networks are generally conserved. Comparative ATAC-seq profiling of Arabidopsis root hair and non-hair cell types revealed extensive similarity as well as many cell type-specific differences. Analyzing TF binding sites in differentially accessible regions identified a MYB-driven regulatory module unique to the hair cell, which appears to control both cell fate regulators and abiotic stress responses. Our analyses revealed common regulatory principles among species and shed light on the mechanisms producing cell type-specific transcriptomes during development.

plant biology↗