The Cost Of Reinforcement: Selection On Flower Color In Allopatric Populations Of Phlox Drummondii*

Reinforcement is the process by which increased reproductive isolation between incipient species evolves due to selection against maladaptive hybrids or costly hybrid mating. Reinforcement is predicted to create a pattern of greater prezygotic reproductive isolation in regions where the two species co-occur, sympatry, than in allopatry. Although most research on reinforcement focuses on understanding the evolutionary forces acting in sympatry, here we consider what prevents the alleles conferring greater reproductive isolation from spreading into allopatry. We investigate flower color divergence in the wildflower Phlox drummondii, which is caused by reinforcement in the regions sympatric with its congener Phlox cuspidata. Specifically, we performed common garden field experiments and pollinator observations to estimate selection acting on flower color variation in allopatry. We combine our estimates of maternal and paternal fitness using simulations and predict how flower color alleles migrating from sympatry will evolve in allopatry. Our results suggest that strong pollinator preference for the ancestral flower color in allopatry can maintain divergence between allopatric and sympatric populations.Integrative Biolog

Accuracy differences between interview formats : examining factors that may influence metamemory utilization.

Eyewitnesses are important for criminal investigations. When interviewing witnesses, police first ask witnesses to describe what they observed. This initial statement is a free narrative (FN) and is usually highly accurate. Next, police ask follow-up questions (FQs), which generate additional information but often at the cost of accuracy. This dissertation aims to examine factors that may contribute to the effect of interview format on accuracy and whether FQ instructions change detail quality provided in follow-up question responses (FQRs). Additionally, individual differences in responding to FQ instructions were explored. Subjects watched a movie clip depicting a crime. Next, subjects filled out personality questionnaires and then typed their FNs. Subjects were then given one of five FQ instructions that encouraged accuracy (Accuracy+), encouraged informativeness (Informative+), encouraged “I don’t know” responses if needed (IDK+), discouraged “I don’t know” responses unless absolutely necessary (IDK-), or only told them they would be asked FQs (Control). Ten variables were used to measure interview quality (e.g., accuracy, precision, quantity). FN quality was compared to FQR quality in the Control condition to determine the effect of interview format, without influence of instructions. FQR quality was compared across FQ conditions to determine the effect of FQ instructions. FQR quality was correlated with conscientiousness and social desirability scores to explore individual differences. Analyses were conducted once using all FQRs and once using only responses if the corresponding FQ topic had been mentioned during the preceding FN. Interview format affected all variables except overall accuracy. This null effect on accuracy does not align with previous interview literature and limited the interpretation of other effects. IDK+ instructions were the only instructions that affected FQR quality. IDK+ subjects said “I don’t know” significantly more frequently, and provided significantly fewer inaccurate details, in FQRs than Control subjects. Yet, IDK+ subjects were not significantly more accurate than Control subjects. Thus, it remains unclear whether IDK+ instructions selectively filter inaccurate details or reduce total detail output. The effects of IDK+ instructions were only significant when using all FQRs. Significant individual differences emerged in Accuracy+, Informative+, and Control conditions when using all FQRs

Liberal And General Studies In Further Education: Voices From The ‘Chalk Face’

This paper presents initial findings from research investigating an important but largely neglected facet of the history of Further Education (FE) – the Liberal Studies and General Studies (LS/GS) movement. Drawing on historical documents and interview data from a group of former LS/GS lecturers, the paper provides important insights into some of the key events and initiatives between the 1950s-1980s, which led to the rise and eventual fall of the LS/GS movement, and seeks to capture the voices of those who were involved at the ‘chalk face’. Whilst it is acknowledged that the quality and nature of LS/GS was often variable and that the experiences of both teachers and learners were often uneven, the central argument of the paper is that many of the principles of the LS/GS movement were not only ahead of their time, but are perhaps more relevant to FE today than ever before

A multidimensional selective landscape drives adaptive divergence between and within closely related Phlox species.

Selection causes local adaptation across populations within species and simultaneously divergence between species. However, it is unclear if either the force of or the response to selection is similar across these scales. We show that natural selection drives divergence between closely related species in a pattern that is distinct from local adaptation within species. We use reciprocal transplant experiments across three species of Phlox wildflowers to characterize widespread adaptive divergence. Using provenance trials, we also find strong local adaptation between populations within a species. Comparing divergence and selection between these two scales of diversity we discover that one suite of traits predicts fitness differences between species and that an independent suite of traits predicts fitness variation within species. Selection drives divergence between species, contributing to speciation, while simultaneously favoring extensive diversity that is maintained across populations within a species. Our work demonstrates how the selection landscape is complex and multidimensional

Helenalin-mediated Post-transcriptional Regulation of p21(Cip1) Inhibits 3T3-L1 Preadipocyte Proliferation

We have previously shown that post-transcriptional mechanisms involving the 26S proteasome regulate the cyclin-dependent kinase inhibitors (CKIs), p21(Cip1) and p27(Kip1) during preadipocyte proliferation. Earlier studies further demonstrated that the anti-inflammatory, anti-carcinogenic phytochemical, helenalin is a potent inhibitor of periodic Skp2 accumulation, an F-box protein mediating SCF E3 ligase ubiquitylation and degradation of both CKIs during S phase progression. Data presented here demonstrate that helenalin dose-dependently induced G1 arrest of synchronously replicating 3T3-L1 preadipocytes. This effect occurred in the absence of discernable indices of cell toxicity or apoptosis under the conditions used in this study. Our results demonstrate that helenalin markedly increased p21 protein accumulation in both density-arrested and proliferating preadipocytes in a dose-dependent manner. This increase in p21 protein abundance occurred without change in mRNA transcript demonstrating that post-transcriptional mechanisms were involved. This notion was further supported by the modest accumulation of polyubiquitylated p21 following treatment with helenalin suggesting that suppression of targeted p21 proteolysis by the 26S proteasome contributed to helenalin-mediated p21 accumulation. The increase in p21 protein was compartmentalized to the nucleus where p21 is known to inhibit cell cycle progression. Finally, helenalin increased protein-protein interactions between p21 and cyclin-dependent kinase 2 (Cdk2) which may account in part for the anti-proliferative effect in 3T3-L1 preadipocytes

Conjugated Linoleic Acid Promotes Human Adipocyte Insulin Resistance through NF?B-dependent Cytokine Production

We previously demonstrated that trans-10, cis-12 conjugated linoleic acid (CLA) reduced the triglyceride content of human adipocytes by activating mitogen-activated protein kinase kinase/extracellular signal-related kinase (MEK/ERK) signaling via interleukins (IL) 6 and 8. However, the upstream mechanism is unknown. Here we show that CLA increased (=6 h) the secretion of IL-6 and IL-8 in cultures containing both differentiated adipocytes and stromal vascular (SV) cells, non-differentiated SV cells, and adipose tissue explants. CLA isomer-specific induction of IL-6 and tumor necrosis factor-a was associated with the activation of nuclear factor ?B (NF?B) as evidenced by 1) phosphorylation of I?Ba, I?Ba kinase, and NF?B p65, 2) I?Ba degradation, and 3) nuclear translocation of NF?B. Pretreatment with selective NF?B inhibitors and the MEK/ERK inhibitor U0126 blocked CLA-mediated IL-6 gene expression. Trans-10, cis-12 CLA suppression of insulin-stimulated glucose uptake at 24 h was associated with decreased total and plasma membrane glucose transporter 4 proteins. Inhibition of NF?B activation or depletion of NF?B by RNA interference using small interfering NF?B p65 attenuated CLA suppression of glucose transporter 4 and peroxisome proliferator-activated receptor ? proteins and glucose uptake. Collectively, these data demonstrate for the first time that trans-10, cis-12 CLA promotes NF?B activation and subsequent induction of IL-6, which are at least in part responsible for trans-10, cis-12 CLA-mediated suppression of peroxisome proliferator-activated receptor ? target gene expression and insulin sensitivity in mature human adipocytes

Impact of reference gene selection for target gene normalization on experimental outcome using real-time qRT-PCR in adipocytes

BACKGROUND: With the current rise in obesity-related morbidities, real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) has become a widely used method for assessment of genes expressed and regulated by adipocytes. In order to measure accurate changes in relative gene expression and monitor intersample variability, normalization to endogenous control genes that do not change in relative expression is commonly used with qRT-PCR determinations. However, historical evidence has clearly demonstrated that the expression profiles of traditional control genes (e.g., ß-actin, GAPDH, a-tubulin) are differentially regulated across multiple tissue types and experimental conditions. METHODOLOGY/PRINCIPAL FINDINGS: Therefore, we validated six commonly used endogenous control genes under diverse experimental conditions of inflammatory stress, oxidative stress, synchronous cell cycle progression and cellular differentiation in 3T3-L1 adipocytes using TaqMan qRT-PCR. Under each study condition, we further evaluated the impact of reference gene selection on experimental outcome using examples of target genes relevant to adipocyte function and differentiation. We demonstrate that multiple reference genes are regulated in a condition-specific manner that is not suitable for use in target gene normalization. CONCLUSION/SIGNIFICANCE: Data are presented demonstrating that inappropriate reference gene selection can have profound influence on study conclusions ranging from divergent statistical outcome to inaccurate data interpretation of significant magnitude. This study validated the use of endogenous controls in 3T3-L1 adipocytes and highlights the impact of inappropriate reference gene selection on data interpretation and study conclusions

Lateralization of infant holding by mothers: a longitudinal evaluation of variations over the first 12 weeks

The maternal preference to hold infants on the left rather than right side of the body was examined longitudinally, with attention to four explanations: maternal monitoring of infant state, maternal handedness, infant proximity to the mother’s heartbeat, and preferred infant head position. The side and site of holding were measured over the first twelve weeks of the lives of 24 infants. Information about group and individual consistency in holding side allowed novel evaluation of the theories. A strong bias to hold on the left dropped below significance when the infants were aged twelve weeks and was limited to specific holding positions. Findings were generally consistent with the monitoring hypothesis, and little support was found for the three alternative explanations