Texas A&M University

About: Texas A&M University is a education organization based out in College Station, Texas, United States. It is known for research contribution in the topics: Population & Gene. The organization has 72169 authors who have published 164372 publications receiving 5764236 citations.

Genomewide Nonadditive Gene Regulation in Arabidopsis Allotetraploids

Abstract: Polyploidy has occurred throughout the evolutionary history of all eukaryotes and is extremely common in plants. Reunification of the evolutionarily divergent genomes in allopolyploids creates regulatory incompatibilities that must be reconciled. Here we report genomewide gene expression analysis of Arabidopsis synthetic allotetraploids, using spotted 70-mer oligo-gene microarrays. We detected >15% transcriptome divergence between the progenitors, and 2105 and 1818 genes were highly expressed in Arabidopsis thaliana and A. arenosa, respectively. Approximately 5.2% (1362) and 5.6% (1469) genes displayed expression divergence from the midparent value (MPV) in two independently derived synthetic allotetraploids, suggesting nonadditive gene regulation following interspecific hybridization. Remarkably, the majority of nonadditively expressed genes in the allotetraploids also display expression changes between the parents, indicating that transcriptome divergence is reconciled during allopolyploid formation. Moreover, >65% of the nonadditively expressed genes in the allotetraploids are repressed, and >94% of the repressed genes in the allotetraploids match the genes that are expressed at higher levels in A. thaliana than in A. arenosa, consistent with the silencing of A. thaliana rRNA genes subjected to nucleolar dominance and with overall suppression of the A. thaliana phenotype in the synthetic allotetraploids and natural A. suecica. The nonadditive gene regulation is involved in various biological pathways, and the changes in gene expression are developmentally regulated. In contrast to the small effects of genome doubling on gene regulation in autotetraploids, the combination of two divergent genomes in allotetraploids by interspecific hybridization induces genomewide nonadditive gene regulation, providing a molecular basis for de novo variation and allopolyploid evolution.

Searching for dark matter annihilation in recently discovered Milky Way Satellites with Fermi-LAT

Abstract: We search for excess gamma-ray emission coincident with the positions of confirmed and candidate Milky Way satellite galaxies using six years of data from the Fermi Large Area Telescope (LAT). Our sample of 45 stellar systems includes 28 kinematically confirmed dark-matter-dominated dwarf spheroidal galaxies (dSphs) and 17 recently discovered systems that have photometric characteristics consistent with the population of known dSphs. For each of these targets, the relative predicted gamma-ray flux due to dark matter annihilation is taken from kinematic analysis if available, and estimated from a distance-based scaling relation otherwise, assuming that the stellar systems are DM-dominated dSphs. LAT data coincident with four of the newly discovered targets show a slight preference (each ~ 2sigma local) for gamma-ray emission in excess of the background. However, the ensemble of derived gamma-ray flux upper limits for individual targets is consistent with the expectation from analyzing random blank-sky regions, and a combined analysis of the population of stellar systems yields no globally significant excess (global significance < 1sigma ). Our analysis has increased sensitivity compared to the analysis of 15 confirmed dSphs by Ackermann et al. The observed constraints on the DM annihilation cross section are statistically consistent with the background expectation, improving by a factor of ~2 for large DM masses ({m}{DM,b\bar{b}}≳ 1 {TeV} and {m}{DM,{tau }+{tau }-}≳ 70 {GeV}) and weakening by a factor of ~1.5 at lower masses relative to previously observed limits.

Thermodynamic parameters in the Earth as determined from seismic profiles

Abstract: Summary. A Debye model using two cut-off frequencies corresponding to compressional and shear velocities is used to calculate mineral entropies. This model permits entropy and heat capacity in the Earth to be calculated from seismic profiles, and iteration yields temperature profiles along an isentrope. With an adiabatic temperature profile it is possible to obtain Griineisen’s parameter and thermal expansion as a function of depth. Only in the lower mantle is the calculated Griineisen’s parameter along an isentrope approximately proportional to volume.

The PedsQL™ in Type 1 and Type 2 Diabetes: Reliability and validity of the Pediatric Quality of Life Inventory™ Generic Core Scales and Type 1 Diabetes Module

Abstract: OBJECTIVE —The Pediatric Quality of Life Inventory (PedsQL) is a modular instrument designed to measure health-related quality of life (HRQOL) in children and adolescents aged 2–18 years. The PedsQL 4.0 Generic Core Scales are child self-report and parent proxy-report scales developed as the generic core measure to be integrated with the PedsQL disease-specific modules. The PedsQL 3.0 Type 1 Diabetes Module was designed to measure diabetes-specific HRQOL. RESEARCH DESIGN AND METHODS —The PedsQL Generic Core Scales and Diabetes Module were administered to 300 pediatric patients with type 1 or type 2 diabetes and 308 parents. RESULTS —Internal consistency reliability for the PedsQL Generic Core Total Scale score (α = 0.88 child, 0.89 parent-report) and most Diabetes Module scales (average α = 0.71 child, 0.77 parent-report) was acceptable for group comparisons. The PedsQL 4.0 distinguished between healthy children and children with diabetes. The Diabetes Module demonstrated intercorrelations with dimensions of generic and diabetes-specific HRQOL. CONCLUSIONS —The results demonstrate the reliability and validity of the PedsQL in diabetes. The PedsQL may be used as an outcome measure for diabetes clinical trials and research.