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Nielsen, D. M.

Publications and source records attributed to Nielsen, D. M..

2 recordsLinked to original sources

Genetic variation in a plant-parasitic nematode is associated with gene expression changes conserved across evolutionarily distant host plants

A hallmark of the interactions between endoparasites (parasites that live within plant tissue) and their hosts, is the parasites ability to hijack host gene expression to support their own existence. While a number of studies have been performed to identify plant genes that are recruited in this process, there is much that remains unknown. One mechanism by which these connections can be explored is using a traditional genetics approach - identifying connections between genetic variation and phenotype variation. To that end, we leverage experiments examining tissue from three host plants, each infected with one of two genetically distinct strains of the endoparasite Meloidogyne hapla. Using gene expression profiles, we identify plant genes that differ based on the genetic background of the parasite, and show that these signals are common across plant hosts. These results indicate that the plant genes recruited by the parasite differ according to the parasites genetic background, and that these alternative patterns are conserved across evolutionarily distant hosts. We also leverage public data to identify conserved host expression differences when comparing M. hapla-infected roots to uninfected root tissue. Finally, we demonstrate that parasite gene expression varies based on the parasites genetic background, and these signals are also conserved when inhabiting different host species.

genomics↗

Assessing the Nucleotide-Level Impact of Spaceflight Stress using RNA-Sequencing Data

Understanding the effects of space radiation and microgravity on DNA integrity is critical to assess the impact of long-term spaceflight. However, studying spaceflights effect on terrestrial life is difficult. NASA created GeneLab, a public Omics database for spaceflight-related data, to help combat these limitations. While GeneLab has very few DNA-based data sets, transcriptome information is abundant. This study used RNA-Seq data from GeneLab to examine DNA sequence variants linked to spaceflight stress exposure. More mutations were observed in spaceflight samples than in the ground control samples. This increase in variants was not reduced in samples grown under artificial gravity in space, suggesting that microgravity did not significantly affect the amount of DNA damage in this experiment. There was also an increase in transversion mutations, consistent with known forms of radiation-induced damage. This work demonstrates that RNA-Seq data is a useful resource for evaluating DNA damage from spaceflight and provides a baseline for the types of mutations that could be detected.

bioinformatics↗