Three clinical Chlamydia pneumoniae isolates for which the MIC of azithromycin increased after treatment were investigated for genetic evidence of macrolide resistance. Attempts to induce antibiotic resistance in vitro were made. No genetic mechanism was identified for the phenotypic change in these C. pneumoniae isolates. No macrolide resistance was obtained in vitro.

Management of agroecosystems with herbicides imposes strong selection pressures on weedy plants leading to the evolution of resistance against those herbicides. Resistance to glyphosate in populations of Lolium perenne L. ssp. multiflorum is increasingly common in California, USA, causing economic losses and the loss of effective management tools. To gain insights into the recent evolution of g...

Genetic manipulation of sheep by selective breeding offers a means to reduce the current reliance on chemotherapy for the control of gastro-intestinal nematodes. Simulated epidemiological studies support this view as, compared to lambs of 'normal' susceptibility, those 'selected' for resistance to Trichostrongylus colubriformis have lower worm burdens and reduced production losses. Considerable...

The objective of this study was to test that genetic variation for resistance to clinical and subclinical diseases exists in growing pigs. A total of 13 551 male growing pigs were assessed for resistance to five categories of clinical and subclinical disease: (i) any clinical or subclinical disease, (ii) lameness, (iii) respiratory diseases, (iv) diarrhoea, and (v) other diseases (i.e. any clin...

Mantel-based tests have been the primary analytical methods for understanding how landscape features influence observed spatial genetic structure. Simulation studies examining Mantel-based approaches have highlighted major challenges associated with the use of such tests and fueled debate on when the Mantel test is appropriate for landscape genetics studies. We aim to provide some clarity in th...

Oxidative stress was recently demonstrated to affect several fitness-related traits and is now well recognized to shape animal life-history evolution. However, very little is known about how much resistance to oxidative stress is determined by genetic and environmental effects and hence about its potential for evolution, especially in wild populations. In addition, our knowledge of phenotypic s...

Multiple mating by females (polyandry) remains hard to explain because, while it has substantial costs, clear benefits have remained elusive. The problem is acute in the social insects because polyandry is probably particularly costly for females and most material benefits of the behavior are unlikely to apply. It has been suggested that a fitness benefit may arise from the more genetically div...

BACKGROUND The development of multidrug resistance is a major problem in the treatment of pathogenic microorganisms by distinct antimicrobial agents. Characterizing the genetic variation among plasmids from different bacterial species or strains is a key step towards understanding the mechanism of virulence and their evolution. RESULTS We applied a deep sequencing approach to 206 clinical str...

Understanding the genetic architecture of traits in breeding programs can be critical for making genetic progress. Important factors include the number of loci controlling a trait, allele frequencies at those loci, and allele effects in breeding germplasm. To this end, multiparental populations offer many advantages for quantitative trait locus (QTL) analyses compared to biparental populations....

We used crosses between two closely related Drosophila species, Drosophila serrata and D. birchii, to examine the genetic basis of desiccation resistance and correlations between resistance, physiological traits, and life-history traits. D. serrata is more resistant to desiccation than D. birchii, and this may help to explain the broader geographical range of the former species. A comparison of...