Inter-Simple Sequence Repeats (ISSR), Microsatellite-Primed Genomic Profiling Using Universal Primers.

Inter-simple sequence repeat (ISSR) markers are highly polymorphic, relatively easy to develop, and inexpensive compared to other methods and have numerous applications. Importantly, the same ISSR primers can potentially be used universally across plant phylogenetic diversity. The basic technique of ISSRs is flexible and can be modified with options for implementation for a broad range of projects and budgets. Ranked in increasing order of technical demand and costs, these are manual agarose and manual polyacrylamide with silver staining and automated using fluorescently labeled primers and capillary electrophoresis. Overall manual agarose-based ISSRs are a sound, safe, easy, and low-cost method for reliably inferring plant genetic diversity. Here, we provide detailed protocols to undertake this fingerprinting method and provide guidance to the literature for the many options available for this technique.

The diverse origins of New Zealand house mice.

Molecular markers and morphological characters can help infer the colonization history of organisms. A combination of mitochondrial (mt) D-loop DNA sequences, nuclear DNA data, external measurements and skull characteristics shows that house mice (Mus musculus) in New Zealand and its outlying islands are descended from very diverse sources. The predominant genome is Mus musculus domesticus (from western Europe), but Mus musculus musculus (from central Europe) and Mus musculus castaneus (from southern Asia) are also represented genetically. These subspecies have hybridized to produce combinations of musculus and domesticus nuclear DNA coupled with domesticus mtDNA, and castaneus or musculus mtDNA with domesticus nuclear DNA. The majority of the mice with domesticus mtDNA that we sampled had D-loop sequences identical to two haplotypes common in Britain. This is consistent with long-term British-New Zealand cultural linkages. The origins of the castaneus mtDNA sequences widespread in New Zealand are less easy to identify.

Diet selectivity in a terrestrial forest invertebrate, the Auckland tree weta, across three habitat zones.

Insects are important but overlooked components of forest ecosystems in New Zealand. For many insect species, information on foraging patterns and trophic relationships is lacking. We examined diet composition and selectivity in a large-bodied insect, the Auckland tree weta Hemideina thoracica, in three habitat zones in a lowland New Zealand forest. We asked whether H. thoracica selectively forage from available plant food sources, and whether these choices were lipid-rich compared to nonpreferred available plants. We also identified the proportion of invertebrates in their frass as a proxy for omnivory. From reconnaissance plot sampling, together with fecal fragment analysis, we report that more than 93% of individual tree weta had eaten invertebrates before capture. Additionally, weta in the highest elevation hillslope habitat zone consumed significantly fewer species of plants on average than weta on the low-elevation terrace habitat. Upper hillslope weta also had the highest average number of invertebrate fragments in their frass, significantly more than weta in the low-elevation terrace habitat zone. Weta showed high variability in the consumption of fruit and seeds across all habitat zones. Generally, we did not observe diet differences between the sexes (although it appears that male weta in the mid-hillslope habitat ate fruits and seeds more voraciously than females), suggesting that the sexes have similar niche breadths and display similar degrees of omnivorous behavior. Extraction of leaf lipids demonstrated a range of lipid content values in available plants, and Ivlev's Electivity Index indicated that plant species which demonstrated high electivity tended to have higher concentrations of lipids in their leaves. Our findings indicate that H. thoracica forage omnivorously and selectively, and hence play multiple roles in native ecosystems and food webs.

Increased inter-colony fusion rates are associated with reduced COI haplotype diversity in an invasive colonial ascidian Didemnum vexillum.

Considerable progress in our understanding of the population genetic changes associated with biological invasions has been made over the past decade. Using selectively neutral loci, it has been established that reductions in genetic diversity, reflecting founder effects, have occurred during the establishment of some invasive populations. However, some colonial organisms may actually gain an ecological advantage from reduced genetic diversity because of the associated reduction in inter-colony conflict. Here we report population genetic analyses, along with colony fusion experiments, for a highly invasive colonial ascidian, Didemnum vexillum. Analyses based on mitochondrial cytochrome oxidase I (COI) partial coding sequences revealed two distinct D. vexillum clades. One COI clade appears to be restricted to the probable native region (i.e., north-west Pacific Ocean), while the other clade is present in widely dispersed temperate coastal waters around the world. This clade structure was supported by 18S ribosomal DNA (rDNA) sequence data, which revealed a one base-pair difference between the two clades. Recently established populations of D. vexillum in New Zealand displayed greatly reduced COI genetic diversity when compared with D. vexillum in Japan. In association with this reduction in genetic diversity was a significantly higher inter-colony fusion rate between randomly paired New Zealand D. vexillum colonies (80%, standard deviation ±18%) when compared with colonies found in Japan (27%, standard deviation ±15%). The results of this study add to growing evidence that for colonial organisms reductions in population level genetic diversity may alter colony interaction dynamics and enhance the invasive potential of newly colonizing species.