Coexistence of Trichome Variation in a Natural Plant Population: A Combined Study Using Ecological and Candidate Gene Approaches

The coexistence of distinct phenotypes within populations has long been investigated in evolutionary ecology. Recent studies have identified the genetic basis of distinct phenotypes, but it is poorly understood how the variation in candidate loci is maintained in natural environments. In this study, we examined fitness consequences and genetic basis of variation in trichome production in a natural population of Arabidopsis halleri subsp. gemmifera. Half of the individuals in the study population produced trichomes while the other half were glabrous, and the leaf beetle Phaedon brassicae imposed intensive damage to both phenotypes. The fitness of hairy and glabrous plants showed no significant differences in the field during two years. A similar result was obtained when sibling hairy and glabrous plants were transplanted at the same field site, whereas a fitness cost of trichome production was detected under a weak herbivory condition. Thus, equivalent fitness of hairy and glabrous plants under natural herbivory allows their coexistence in the contemporary population. The pattern of polymorphism of the candidate trichome gene GLABROUS1 (GL1) showed no evidence of long-term maintenance of trichome variation within the population. Although balancing selection under fluctuating biotic environments is often proposed to explain the maintenance of defense variation, the lack of clear evidence of balancing selection in the study population suggests that other factors such as gene flow and neutral process may have played relatively large roles in shaping trichome variation at least for the single population level

Accountability to Prevent Corruption in Construction Projects

This article was published in the Journal of Construction Engineering and Management [© ASCE] and the definitive version is available at: http://pubs.asce.org/journals/construction/ or http://cedb.asce.orgThe American Society of Civil Engineers claim that corruption accounts for an estimated $340 billion of worldwide construction costs each year. Corruption (including bribery, embezzlement, kickbacks and fraud) in construction projects undermines the delivery of infrastructure services. Furthermore, corruption poses significant risks to construction and engineering companies themselves. What progress has been made, therefore, in reducing the risk of corruption to construction projects? It is the purpose of this paper to argue that with improved accountability, attention to ethics and cultural considerations, and reduced corruption, it is possible to construct, operate and maintain adequate quality and quantity of infrastructure on a more sustainable basis and thereby improve construction practice. This paper will demonstrate how accountability initiatives in construction projects, in developed and developing countries can be of benefit internationally to the public and private sector as well as Non Government Organisations and researchers in their efforts to reduce corruption in infrastructure services