Biology subjects

Vaughn, M.

Publications and source records attributed to Vaughn, M..

3 recordsLinked to original sources

bioRxiv2017

Subtle perturbations of the maize methylome reveal genes and transposons silenced by DNA methylation

DNA methylation is a chromatin modification that can provide epigenetic regulation of gene and transposon expression. Plants utilize several pathways to establish and maintain DNA methylation in specific sequence contexts. The chromomethylase (CMT) genes maintain CHG (where H = A, C or T) methylation. The RNA-directed DNA methylation (RdDM) pathway is important for CHH methylation. Transcriptome analysis was performed in a collection of Zea mays lines carrying mutant alleles for CMT or RdDM-associated genes. While the majority of the transcriptome was not affected, we identified sets of genes and transposon families sensitive to context-specific decreases in DNA methylation in mutant lines. Many of the genes that are up-regulated in CMT mutant lines have high levels of CHG methylation, while genes that are differentially expressed in RdDM mutants are enriched for having nearby mCHH islands, providing evidence that context-specific DNA methylation directly regulates expression of a small number of genes. The analysis of a diverse set of inbred lines revealed that many genes regulated by CMTs exhibit natural variation for DNA methylation and gene expression. Transposon families with differential expression in the mutant genotypes show few defining features, though several families up-regulated in RdDM mutants show enriched expression in endosperm, highlighting the importance for this pathway during reproduction. Taken together, our findings suggest that while the number of genes and transposon families whose expression is reproducibly affected by mild perturbations in context-specific methylation is small, there are distinct patterns for loci impacted by RdDM and CMT mutants.

plant biology↗

bioRxiv2017

The Association of Externalizing and Internalizing Problems with Indicators of Intelligence in a Sample of At-Risk Children

To date, a substantial body of research exists suggesting an association between indicators of intelligence and various deleterious outcomes, including externalizing and internalizing behavioral problems. Much of this research, however, has focused on samples drawn from the general population, thus it remains less clear how (and if) intelligence relates to problem behaviors in samples of highly at-risk individuals. The current study seeks to contribute to this knowledge base by examining the associations between intelligence and internalizing, externalizing, and total scores on the Child Behavioral Checklist in a sample of approximately 2,500 highly disadvantaged respondents considered by Child Protective Services as at-risk for abuse or neglect. While the two measures of intelligence performed differently, there emerged some association between overall lower IQ and higher total behavioral problem scores. There was some evidence that low IQ also predicted higher internalizing scores, but this relationship varied greatly by measure and model. Results, limitations, and implications of the current study are discussed.

neuroscience↗

bioRxiv2017

Resting heart rate and psychopathy: Findings from the Add Health Survey

Despite the prior linkages of low resting heart rate to antisocial behavior broadly defined, less work has been done examining possible associations between heart rate to psychopathic traits. The small body of research on the topic that has been conducted so far seems to suggest an inverse relationship between the two constructs. A smaller number of studies have found the opposite result, however, and some of the previous studies have been limited by small sample sizes and unrepresentative samples. The current study attempts to help clarify the relationship between resting heart rate and psychopathic traits in a large, nationally representative sample (analytical N ranged from 14,173-14,220) using an alternative measure of psychopathic traits that is less focused on antisocial processes, and rooted in personality traits. No significant relationship between heart rate and psychopathic traits, or heart rate and a measure of cold heartedness, was found after controlling for age, sex, and race. Implications of the findings, study limitations, and directions for future research are discussed.

physiology↗