Evolutionary genetics: jumping into a new species.

A new study finds a dramatic increase in transposable element numbers in three new sunflower hybrid species, and may suggest a novel role for transposable elements in speciation.

Gene expression divergence and the origin of hybrid dysfunctions.

Hybrids between closely related species are often sterile or inviable as a consequence of failed interactions between alleles from the different species. Most genetic studies have focused on localizing the alleles associated with these failed interactions, but the mechanistic/biochemical nature of the failed interactions is poorly understood. This review discusses recent studies that may contribute to our understanding of these failed interactions.

Speciation genetics: evolving approaches.

Much progress has been made in the past two decades in understanding Darwin's mystery of the origins of species. Applying genomic techniques to the analysis of laboratory crosses and natural populations has helped to determine the genetic basis of barriers to gene flow which create new species. Although new methodologies have not changed the prevailing hypotheses about how species form, they have accelerated the pace of data collection.

Genome-wide patterns of expression in Drosophila pure species and hybrid males. II. Examination of multiple-species hybridizations, platforms, and life cycle stages.

Species often produce sterile hybrids early in their evolutionary divergence, and some evidence suggests that hybrid sterility may be associated with deviations or disruptions in gene expression. In support of this idea, many studies have shown that a high proportion of male-biased genes are underexpressed, compared with non-sex-biased genes, in sterile F1 male hybrids of Drosophila species. In this study, we examined and compared patterns of misexpression in sterile F1 male hybrids of Drosophila simulans and 2 of its sibling species, Drosophila mauritiana and Drosophila sechellia, at both the larval and adult life stages.

Gene transposition as a cause of hybrid sterility in Drosophila.

We describe reproductive isolation caused by a gene transposition. In certain Drosophila melanogaster-D. simulans hybrids, hybrid male sterility is caused by the lack of a single-copy gene essential for male fertility, JYAlpha.

Effects of atazanavir/ritonavir and lopinavir/ritonavir on glucose uptake and insulin sensitivity: demonstrable differences in vitro and clinically.

Background: The HIV protease inhibitor (PI) atazanavir does not impair insulin sensitivity acutely but ritonavir and lopinavir induce insulin resistance at therapeutic concentrations.

Objective: To test the hypothesis that atazanavir combined with a lower dose of ritonavir would have significantly less effect on glucose metabolism than lopinavir/ritonavir in vitro and clinically.

Methods: Glucose uptake was measured following insulin stimulation in differentiated human adipocytes in the presence of ritonavir (2 micromol/l) combined with either atazanavir or lopinavir (3-30 micromol/l).

The role of geranylgeranylated proteins in human mesangial cell proliferation.

The Rho family of guanine 5'-triphosphatases (GTPases) play a key role in regulating cell proliferation, tubulointerstitial fibrosis, and glomerular hemodynamics. The post-translational prenylation of RhoGTPases by the addition of a geranylgeranyl moiety is critical for cellular localization and signaling activity. This study investigates the effects of (i) inhibiting geranylgeranylation (GG) in human mesangial cell (HMC) proliferation and apoptosis, using GGTI 298, a specific inhibitor of GG and (ii) lovastatin, an HMG-coacetyl A-reductase inhibitor, which depletes the availability of prenylation substrates.

No evidence for learned mating discrimination in male Drosophila pseudoobscura.

Background: Since females often pay a higher cost for heterospecific matings, mate discrimination and species recognition are driven primarily by female choice. In contrast, frequent indiscriminate matings are hypothesized to maximize male fitness. However, recent studies show that previously indiscriminate males (e.

Data sharing: how much doesn't get submitted to GenBank?

Funding agencies and journals require researchers to deposit DNA sequences in public databases such as GenBank when the paper is published, but how often do authors fail to do so?

The importance of demographic niches to tree diversity.

Most ecological hypotheses about species coexistence hinge on species differences, but quantifying trait differences across species in diverse communities is often unfeasible. We examined the variation of demographic traits using a global tropical forest data set covering 4500 species in 10 large-scale tree inventories. With a hierarchical Bayesian approach, we quantified the distribution of mortality and growth rates of all tree species at each site.

Oral health status among Kenyans in a rural arid setting: dental caries experience and knowledge on its causes.

Objective: To determine the dental caries experience and knowledge on the causes and preventive measures for dental diseases.

Design: A community based cross-sectional descriptive study.

Setting: Elwak sub-district hospital, North Eastern Province, Kenya.

A recombinational portrait of the Drosophila pseudoobscura genome.

Drosophila pseudoobscura has been intensively studied by evolutionary biologists for over 70 years. The recent publication of the genome sequence not only permits studies of comparative genomics with other dipterans but also opens the door to identifying genes associated with adaptive traits or speciation or testing for the signature of natural selection across the genome. Information on regional rates of recombination, localization of inversion breakpoints distinguishing it from its sibling species D.

Simulating natural conditions in the laboratory: a re-examination of sexual isolation between sympatric and allopatric populations of Drosophila pseudoobscura and D. persimilis.

Simulating natural conditions in the laboratory poses one of the most significant challenges to behavioral studies. Some authors have argued that laboratory "choice" experiments reflect mate choice in nature more accurately than "no-choice" experiments. A recent choice experiment study questioned the conclusions of several earlier studies by failing to detect a published difference in sexual isolation between populations of Drosophila pseudoobscura, and suggested their result was more robust because of the more realistic design.

Body fat and other metabolic effects of atazanavir and efavirenz, each administered in combination with zidovudine plus lamivudine, in antiretroviral-naive HIV-infected patients.

Background: Protease inhibitor treatment of human immunodeficiency virus (HIV)-infected individuals has been linked to the development of lipodystrophy. The effects of atazanavir on body fat distribution and related metabolic parameters were examined in antiretroviral-naive patients.

Methods: HIV-positive patients with CD4 cell counts > or = 100 cells/mm3 were randomized to 1 of 2 treatment arms: (1) atazanavir, 400 mg given once daily, plus efavirenz placebo; or (2) efavirenz, 600 mg given once daily, plus atazanavir placebo; each drug was administered with fixed-dose zidovudine (300 mg) and lamivudine (150 mg) given twice daily, and patients were treated for at least 48 weeks.

Evidence for a one-allele assortative mating locus.

Theoretical models have shown that speciation with gene flow can occur readily via a "one-allele mechanism," where the spread of the same allele within both of two diverging species reduces their subsequent hybridization. Here we present direct genetic evidence for such an allele in Drosophila pseudoobscura. Alleles conferring high or low assortative mating in D.

Effects of storage conditions of Moringa oleifera seeds on its performance in coagulation.

Moringa oleifera is a plant whose seeds have coagulation properties for treating water and wastewater. In this study the coagulation efficiency of Moringa oleifera kept in different storage conditions were studied. The Moringa oleifera seeds were stored at different conditions and durations; open container and closed container at room temperature (28 degrees C) and refrigerator (3 degrees C) for durations of 1, 3 and 5 months.

Patterns of evolution of genes disrupted in expression in Drosophila species hybrids.

Divergence between species in regulatory pathways may contribute to hybrid incompatibilities such as sterility. Consistent with this idea, genes involved in male fertility often evolve faster than most other genes both in amino acid sequence and in expression. Previously, we identified a panel of male-specific genes under-expressed in sterile male hybrids of Drosophila simulans and D.

Likelihoods from summary statistics: recent divergence between species.

We describe an importance-sampling method for approximating likelihoods of population parameters based on multiple summary statistics. In this first application, we address the demographic history of closely related members of the Drosophila pseudoobscura group. We base the maximum-likelihood estimation of the time since speciation and the effective population sizes of the extant and ancestral populations on the pattern of nucleotide variation at DPS2002, a noncoding region tightly linked to a paracentric inversion that strongly contributes to reproductive isolation.

The inhibition of human mesangial cell proliferation by S-trans, trans-farnesylthiosalicylic acid.

Background: Many of the proliferative cytokines implicated in human mesangial cell (HMC) proliferation signal through the superfamily of Ras GTPases. The Ras antagonist, S-trans, trans- farnesylthiosalicylic acid (FTS), was used to investigate the effects of the inhibition of Ras signaling on HMC proliferation.

Methods: Ras expression and membrane localization, MAPK, and Akt activation were analyzed by Western blotting.

New predictive equations for estimation of basal metabolic rates of adolescents: tropics versus temperate.

The energy and nutritional requirements of adolescents are influenced primarily by the growth spurt that occurs at puberty, and also by the need to maintain adequate levels of physical activity. Predictions of BMR have gained attention since the publication of the FAO/WHO/UNU (1985) expert consultation report, which adopted the principle of relying on energy expenditure rather than energy intake to derive requirement of individuals. While the report predicts BMR accurately in many individuals from temperate climate, they are said to be less accurate in predicting BMR in populations living in the tropics.

Endoplasmic reticulum stress links dyslipidemia to inhibition of proteasome activity and glucose transport by HIV protease inhibitors.

The lipid and metabolic disturbances associated with human immunodeficiency virus (HIV) protease inhibitor therapy in AIDS have stimulated interest in developing new agents that minimize these side effects in the clinic. The underlying explanation of mechanism remains enigmatic, but a recently described link between endoplasmic reticulum (ER) stress and dysregulation of lipid metabolism suggests a provocative integration of existing and emerging data. We provide new evidence from in vitro models indicating that proteasome inhibition and differential glucose transport blockade by protease inhibitors are proximal events eliciting an ER stress transcriptional response that can regulate lipogenic pathways in hepatocytes or adipocytes.

Comparative genome sequencing of Drosophila pseudoobscura: chromosomal, gene, and cis-element evolution.

We have sequenced the genome of a second Drosophila species, Drosophila pseudoobscura, and compared this to the genome sequence of Drosophila melanogaster, a primary model organism. Throughout evolution the vast majority of Drosophila genes have remained on the same chromosome arm, but within each arm gene order has been extensively reshuffled, leading to a minimum of 921 syntenic blocks shared between the species. A repetitive sequence is found in the D.

Variation in recombination rate may bias human genetic disease mapping studies.

The availability of the human genome sequence and variability information (as from the International HapMap project) will enhance our ability to map genetic disorders and choose targets for therapeutic intervention. However, several factors, such as regional variation in recombination rate, can bias conclusions from genetic mapping studies. Here, we examine the impact of regional variation in recombination rate across the human genome.