The ability of DNA screening techniques such as Temperature Gradient Gel Electrophoresis (TGGE) and Heteroduplex Analysis to provide resolution approaching that provided by DNA sequencing for a fraction of the time, effort and expense point to them as the logical successor to allozyme electrophoresis for population genetics. Here we present a novel alternative to the standard TGGE/Heteroduplex Analysis protocol - Outgroup Heteroduplex Analysis (OHA). We assess this technique's sensitivity in comparison to previous screening approaches using a known hierarchy of sequence differences. Our data show that Outgroup Heteroduplex Analysis has greatly increased sensitivity for screening DNA variants from that of TGGE used alone and is easily applicable to large numbers of samples. Using this technique we can consistently detect differences of as small as one base change in a 433-base-pair fragment of Control Region mitochondrial DNA from Melomys cervinipes (an Australian rodent). The approach should easily be extendable to nuclear loci and is not necessarily dependent on the use of a denaturing gradient. When combined with a targeted sequencing effort, OHA provides a sensitive and simple means of obtaining allele/haplotype frequencies and their phylogenies for population and phylogeographic studies in molecular ecology.

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This study investigated the interspecific amplification of 35 microsatellite loci developed for M. alternifolia across seven other species within the Myrtaceae. All the primers used gave successful amplification of loci in at least one of the species tested. The level of success varied between species; 88.6% of primers gave amplification products for Melaleuca spp., 74.3% for Callistemon salignus, 45.7% for Eucalyptus spp. and 25.7% for Backhousia citriodora. Sequencing of a number of amplification products confirmed the presence of microsatellites in those loci. This study shows that the development of species-specific microsatellite libraries might not always be necessary. Cross-species amplification could enable the application of microsatellite technology to studies with limited resources, a feature characteristic of conservation projects.

Antibiotics on the surface of ants inhibit pathogenic microorganisms and significantly lower pollen viability. However, the viability of pollen in contact with the integument of Apis mellifera L. and Vespula germanica (F.) is not significantly lowered. Trigona curbonaria Smith induces some reduction in pollen viability and this may be the effect of resins harvested for nest construction. The disruption of pollen function by T. carbonaria is much less severe than that produced by ants. Differential integurnental effects on pollen are consistent with the relative abundance of bee, wasp and ant pollination systems, particularly the extreme rarity of pollination by ants.