Analysis of Genetic Diversity amongIxoraCultivars (Rubiaceae) using Random Amplified Polymorphic DNA

We have optimized the genomic DNA extraction method from freshand dry laminas, as well as fresh and dry corolla lobes ofIxoracultivars.Some woody tropical species such as these contain excessiveamounts of phenolic compounds that co-precipitate with DNA resultingin poor or no amplification during the polymerase chain reaction(PCR). Repeated precipitation with CsCl coupled with phenol:chloroformextraction yielded high quality DNA suitable for consistentPCR amplification. The DNA from fresh laminas of 22 cultivarsofIxorawas subjected to random amplified polymorphic DNA (RAPD)analysis. Individual taxa could be identified using specificDNA markers from the RAPD profiles. Cluster analysis of datafrom six primers grouped all 22 cultivars distinctly under twocultivar groups, viz.,IxoraCoccinea andI.Javanica. The percentagegenetic similarity was calculated for all the cultivars basedon the RAPD data. The two cultivar groups and the outgroup plantswere also clearly distinguishable with polar ordination usinga matrix of genetic dissimilarities (one minus similarity).Our data indicate that besides the use of RAPD markers for identificationof particularIxoracultivars within a germplasm collection, thephylogenetic relationships generated by RAPD analysis may beuseful for future breeding programmes. IxoraL. cultivars; Rubiaceae; RAPD fingerprinting; DNA extraction; woody tropical species     

DNA quantification is technically feasible and of value in cervical smear samples: possible applications for determination of progression in low grade dyskaryosis

This study evaluates the feasibility of DNA analysis of cervical intraepithelial neoplasia III (CIN III) lesions on cervical smear and formalin-fixed paraffin-embedded tissue (FFPET) blocks with a view to extending this type of analysis to milder grades of dyskaryosis. DNA ploidy was determined by image analysis using a CAS 200 Image Analyser. Seventeen patients with a diagnosis of CIN III were studied. Results show that all smear and tissue samples were non-diploid with nine aneuploid and eight tetraploid lesions. In 6/7 patients whose smears and corresponding biopsies were examined there was complete agreement as to the DNA profile. We conclude that DNA quantification is technically feasible in archival, routinely prepared cervical smears. This technique should now be applied to CINI and CINII cervical smears to determine if it is of value in identifying those lesions that will progress to CIN III. This study is particularly timely with the possibility in the near future of estimation of ploidy by image analysis using instruments such as the Highly Optimized Microscope Environment (HOME) system.     

Landscape Development and Coastal Wetland Losses in the Northern Gulf of Mexico

The causes of the extensive (0.86%/yr; 288,414 ha/yr) and welldocumented dramatic and accelerating rate of coastal wetlandloss in the northern Gulf of Mexico were investigated by aninterdisciplinary university research team to discern the roleof outer continental shelf development. The landscape changesand potential causal agents are emphasized herein. Natural drivingfactors include sea level rise and geological compaction, whichappear to remain constant this century, and sediment supplyfrom the Mississippi River which has declined by 50%,since the1950s. Man-made influences include hydrologic changes from riverdiversions, flood protection levees, an extensive canal andspoil bank network, belowground fluid withdrawal and accidentaland intentional impoundments. Wetland loss is not simply a geologicalphenomenon. Wetland plants hold sediments together, add to verticalaccretion rates, withstand storm winds and waves, and assistin sediment trapping. Plant physiologic stress is documentedwhere hydrologic changes occur, and much of the wetland losscould be attributed to the effects of soil waterlogging on plants,not to sediment deprivation.