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Hewavithana, T.

Publications and source records attributed to Hewavithana, T..

2 recordsLinked to original sources

Exploring The Genome of The Oribatid Mite, Oppia Nitens: Environmental Stress Response and Toxicity Adaptation

Oribatid mites are one of the most abundant groups of microarthropods in soil. Oppia nitens, belonging to the family Oppiidae, one of the largest and most diverse families of oribatid mites, has been developed as a standardized model test organism for assessing soil contamination. However, the limited availability of genomic information for this species hinders our understanding of its physiological adaptation and sensitivity to chemical and environmental stressors in soil. Hence, we present the annotated O. nitens draft genome assembled using both Oxford Nanopore Technologies and Illumina sequencing platforms as a basis to identify potential genes that can be linked to adaptation to chemical and environmental stressors. The sequences were assembled into 65 scaffolds spanning 125.4Mb with a 24.5% GC content and an N50 length of 4.41Mb. Genome quality and completeness were checked using arthropod Benchmarking Universal Single-Copy Orthologs (BUSCO) analysis, which identified 93.5 % complete single-copy orthologs, 3.4% complete but duplicated orthologs, 0.5% fragmented, and 2.6% missing orthologs (n=2934). The NCBI Eukaryotic Genome Annotation Pipeline annotated 15,291 genes, 16,969 mRNAs, and 14,938 proteins. Here, we describe the O. nitens complete draft genome and discuss its utility as a genetic basis for further investigations and understanding of the molecular mechanisms and physiological functions in adaptations to environmental change, especially tolerance to metal stress.

genomics↗

Legume genome structures and histories inferred from Cercis canadensis and Chamaecrista fasciculata genomes

O_LIThe legume family originated ca. 70 million years ago and soon diversified into at least six lineages (now extant subfamilies). The signal of whole genome duplications (WGD) is apparent in species sampled from all six subfamilies. The early diversification has posed difficulties for resolving the legume backbone structure and the timing of WGDs. C_LIO_LIIn this study, we report the genome sequences and annotations for Cercis canadensis (Cercidoideae) and Chamaecrista fasciculata (Caesalpinoideae) to help resolve the relative taxonomic placements along the legume backbone, the timings of WGDs relative to subfamily origins, and the ancestral legume karyotype. C_LIO_LIAnalyses of genome assemblies from four subfamilies within Fabaceae show that the last common ancestor of all legumes likely had seven chromosomes, with a genome structure similar to the extant Cercis genome. Our analysis supports an allopolyploid origin of the subfamily Caesalpinoideae, with progenitors involving lineages along the backbone of the legume phylogeny. C_LIO_LIA probable allopolyploid origin of Caesalpinoideae subfamily provides a partial explanation for the difficulty in resolving the structure of the legume backbone. The retained karyotype structure and lack of a WGD in the last 100+ Mya, underscore the utility of the Cercis genome as an ancestral reference for the legume family. C_LI

genomics↗