<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Xue, Xia</style></author><author><style face="normal" font="default" size="100%">Bishwo N. Adhikari</style></author><author><style face="normal" font="default" size="100%">Ball, Becky</style></author><author><style face="normal" font="default" size="100%">John E. Barrett</style></author><author><style face="normal" font="default" size="100%">Miao, Jinxin</style></author><author><style face="normal" font="default" size="100%">Perkes, Ammon</style></author><author><style face="normal" font="default" size="100%">Martin, Mac</style></author><author><style face="normal" font="default" size="100%">Breana L. Simmons</style></author><author><style face="normal" font="default" size="100%">Diana H. Wall</style></author><author><style face="normal" font="default" size="100%">Byron Adams</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Ecological stoichiometry drives the evolution of soil nematode life history traits</style></title><secondary-title><style face="normal" font="default" size="100%">Soil Biology and Biochemistry</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">elemental stoichiometry</style></keyword><keyword><style  face="normal" font="default" size="100%">growth rate hypothesis</style></keyword><keyword><style  face="normal" font="default" size="100%">life history theory</style></keyword><keyword><style  face="normal" font="default" size="100%">molecular evolution</style></keyword><keyword><style  face="normal" font="default" size="100%">nematoda</style></keyword><keyword><style  face="normal" font="default" size="100%">rRNA</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2023</style></year><pub-dates><date><style  face="normal" font="default" size="100%">02/2023</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://www.sciencedirect.com/science/article/pii/S0038071722003480</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">177</style></volume><pages><style face="normal" font="default" size="100%">108891</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Ecological stoichiometry is a useful theoretical framework for understanding the sources and controls on nutrient availability that structure the composition and diversity of biotic communities. One such relationship is that organismal development rate is positively linked to cellular Phosphorus (P). We hypothesized that P availability, relative to other nutrients, e.g., nitrogen and carbon, would drive the evolution of traits associated with organismal growth and development. We examined the effects of P availability both &lt;i&gt;in situ&lt;/i&gt; and &lt;i&gt;in vitro&lt;/i&gt;, on free-living soil nematodes. We found that P-deficient environments produce predictable changes in the ecology and evolution of important life history traits. Our results identify altered rRNA gene copy number and subsequent changes in gene expression and protein synthesis as mechanisms by which P-deficiency influences these traits. These findings have important implications for explaining soil ecological and evolutionary patterns across multiple levels of organization, including the structure and functioning of organisms, populations, communities, and ecosystems.&lt;/p&gt;</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>32</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Xue, Xia</style></author><author><style face="normal" font="default" size="100%">Byron Adams</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Genomics and transcriptomics of Antarctic nematodes reveal drivers of life history evolution and genome evolution</style></title><secondary-title><style face="normal" font="default" size="100%">Department of Biology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Antarctic nematodes</style></keyword><keyword><style  face="normal" font="default" size="100%">Caenorhabditis elegans</style></keyword><keyword><style  face="normal" font="default" size="100%">genome evolution</style></keyword><keyword><style  face="normal" font="default" size="100%">growth rate hypothesis</style></keyword><keyword><style  face="normal" font="default" size="100%">Plectus murrayi</style></keyword><keyword><style  face="normal" font="default" size="100%">Scottnema lindsayae</style></keyword><keyword><style  face="normal" font="default" size="100%">transcriptome</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2018</style></year></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://search.proquest.com/docview/2081899003</style></url></web-urls></urls><publisher><style face="normal" font="default" size="100%">Brigham Young University</style></publisher><pub-location><style face="normal" font="default" size="100%">Provo, UT</style></pub-location><volume><style face="normal" font="default" size="100%">Ph.D.</style></volume><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;Elemental stoichiometry defines a critical understanding of the relationship between&amp;nbsp;nutrient availability and usage throughout different levels of the biological community. We&amp;nbsp;found there is a link between available phosphorus (P), cellular phosphorus, and nematode development as postulated by the growth rate hypothesis (GRH). I predicted that in a P-poor environment, cellular RNA concentrations would be lower than they are in P-rich environment, and thus the 18srRNA expression level will have reduced. To most efficiently regulate the&amp;nbsp;uptake of limited P, I predicted that nematodes in P-poor environments would decrease the number of copies of the 18s rRNA gene in their genome. I measured life history traits as well as rRNA gene expression and gene copy number. We found that elemental stoichiometry predicts evolutionary changes consistent with the Growth Rate Hypothesis. We sequenced and assembled a draft genome of &lt;em&gt;P. murrayi&lt;/em&gt;. Although we expected to find genes responsible for stress tolerance, we hypothesized that in response to strong selection pressure associated with living in&amp;nbsp;a simplified ecosystem, over time the genome of &lt;em&gt;P. murrayi&lt;/em&gt; should have undergone significant decay (gene loss) relative to species in ecosystems structured more strongly by biotic interactions. We found significantly fewer genes in &lt;em&gt;P. murrayi&lt;/em&gt;. To compare patterns of gene expression between two highly divergent Antarctic nematode species, we sequenced and assembled the transcriptomes of &lt;em&gt;S. lindsayae&lt;/em&gt; and &lt;em&gt;P. murrayi&lt;/em&gt;. Under laboratory conditions at 4&amp;nbsp; ̊C, &lt;em&gt;S. lindsayae&lt;/em&gt; had significantly lower rates of gene expression but expressed a significantly larger number of genes. We speculate that the differences in gene expression are correlated with life history traits (developmental rates) while the differences in the number of genes expressed can be explained&amp;nbsp;by their different genetic systems (&lt;em&gt;S. lindsayae&lt;/em&gt; is amphimictic, &lt;em&gt;P. murrayi&lt;/em&gt; is parthenogenic) and the soil environments to which they are adapted. Since we previously showed that differences in available P content can influence the evolution of gene expression via gene copy number, and that this ultimately influences growth rate, we wondered how much of this response is driven by genetics versus how strongly these patterns are driven by temperature. To better understand this, we maintained wild type populations of P. murrayi in P-rich and P-poor conditions at 5&amp;nbsp; ̊C, 10&amp;nbsp; ̊C and 15 ̊C in the laboratory for over 40 generations and sequenced the transcriptomes prepared from each treatment group. We found that nutrient levels played an important role in gene expression when the temperature is optimal for P. murrayi culturing and that temperature is more important in gene expression when the available P is limited. This work underscores the utility of using principles of elemental stoichiometry coupled with genomic and transcriptomics research tools to make and test predictions about life history evolution. The results of my work also&amp;nbsp;inform inferences about the ways in which nutrient availability also drives the organization of trophic interactions and ultimately ecosystems.&lt;/p&gt;</style></abstract><work-type><style face="normal" font="default" size="100%">doctoral</style></work-type></record></records></xml>