Considerations for measuring genetic variation and population structure with multilocus fingerprinting

Multilocus DNA fingerprinting provides a cost-effective means to rapidly assay genetic variation at many loci. While this makes the technique particularly attractive for studies of evolution and conservation biology, fingerprint data can be difficult to interpret. Measurement errors inherent with the technique force investigators to group similar-sized alleles (bands) into discrete bins before estimating genetic parameters. If too little error is accounted for in this process homologous alleles will not be grouped in a common bin, whereas overestimated error can produce bins with homoplasic alleles. We used simulations and empirical data for two frog species ( Rana luteiventris and Hyla regilla ) to demonstrate that mean band-sharing ( S¯_xy ) and heterozygosity ( H ¯_E) are a function of both bin width and band profile complexity (i.e. number and distribution of bands). These estimators are also sensitive to the number of lanes included in the analysis when bin width is wide and a floating bin algorithm is employed. Multilocus estimates of H ¯_E were highly correlated with S¯_xy and thus provide no additional information about genetic variation. Estimates of population subdivision ( F ^ and Φ^_ST) appeared robust to changes in bin size. We also examined the issue of statistical independence for band-sharing data when comparisons are made among all samples. This analysis indicated that the covariance between band-sharing statistics was very small and not statistically different from zero. We recommend that sensitivity analyses for bin size be used to improve confidence in the biological interpretation of multilocus fingerprints, and that the covariance structure for band-sharing statistics be examined.     

ALTERNATIVE PSYCHOTHERAPEUTIC PRACTICE AMONG MIDDLE CLASS AMERICANS: II: SOME CONCEPTUAL AND PRACTICAL COMPARISONS

This article will contextualize ethnographic and clinicalfeatures that distinguish one particular alternativehealing method (Self-Acceptance Training) frommainstreampsychotherapeutic procedures. Factors common to manypsychotherapies are listed and a series of contrasts andcomparisons made by examining definitions of: (1) presentingproblems, (2) inciting events, (3) phasic development, (4)taxonomic classifications, (5) therapeutic interventions,and (6) prognostic formulations. The alternative method oftreatment described in a companion publication(SAT) is used to makesome specific comparisons (Zatzick and Johnson 1997).Baschs (1980) concise recording of a dynamic therapy isborrowed for purposes of a comparative hypothetical treatmentof his patient through a Self-Acceptance Training session.Some directions for future work are suggested.     

Methane flux from Missippi River deltaic plain wetlands

Methane emissions from three wetland habitats in the MississippiRiver deltaic plain were measured over a three year period. Fluxdata collected indicate that each habitat was a net source of methane to the atmosphere throughout the year. Average emissionfrom a Taxodium distichum / Nyssa aquatica (bald cypress / watertupelo) swamp forest was 146 ± 199 mgCH₄ m^-2d^-1 whileemissions from a Sagittaria lancifolia (bulltongue) freshwatermarsh averaged 251 ± 188 mg CH₄m^-2d^-1. Methane flux from a Spartina patens / Sagittaria lancifolia intermediate marsh was significantlyhigher, 912 ± 923 mg CH₄m^-2d^-1. Seasonal variation wassignificant with emissions being higher in the late summer andearly fall. Significant diurnal emissions were observed fromthe Sagittaria lancifolia marsh site. Soil temperature (5 and 10 cm depths) was found to be significantly correlated with methaneemission from the three sites.     

Soluble nitrogen and phosphorus excretion of exotic freshwater mussels (Dreissena spp.): potential impacts for nutrient remineralisation in western Lake Erie

1. Recent increases in phytoplankton biomass and the recurrence of cyanobacterial blooms in western Lake Erie, concomitant with a shift from a community dominated by zebra mussels (Dreissena polymorpha) to one dominated by quagga mussels (D. bugensis), led us to test for differences in ammonia‐nitrogen and phosphate‐phosphorus excretion rates of these two species of invasive molluscs. 2. We found significant differences in excretion rate both between size classes within a taxon and between taxa, with zebra mussels generally having greater nutrient excretion rates than quagga mussels. Combining measured excretion rates with measurements of mussel soft‐tissue dry weight and shell length, we developed nutrient excretion equations allowing estimation of nutrient excretion by dreissenids. 3. Comparing dreissenid ammonia and phosphate excretion with that of the crustacean zooplankton, we demonstrated that the mussels add to nitrogen and phosphorus remineralisation, shortening nitrogen and phosphorus turnover times, and, importantly, modify the nitrogen and phosphorus cycles in Lake Erie. The increased nutrient flux from dreissenids may facilitate phytoplankton growth and cyanobacterial blooms in well‐mixed and/or shallow areas of western Lake Erie.     

The Effect of Red and Far-red Light on Subsequent Enzyme Activity in Arena Coleoptiles

The effect of red light (660 nm), far-red light (730 nm) and dark treatment on the subsequent enzyme activity in homogenates of Avena coleoptiles was investigated. The activities of succinic dehydrogenase (SDH), lactic dehydro-genase (LDH) and glucose-6-P dehydrogenase (GDH) were investigated. The activity of SDH was greatest in material receiving continuous darkness. LDH and GDH activity was stimulated by both light treatments compared with the dark values. Little or no difference in enzyme activity was found using either a single 15 min flash of light or continuous light for 24 h. Admixtures of extracts from dark treated and light treated material in a 1:1 ratio gave unexpected levels of enzyme activity. In all cases such admixtures gave much less than the anticipated enzyme activity.     

Excitatory Transmission in Insect Neuromuscular Systems

Many, but not all, visceral muscles in insects are innervatedby neurosecretory axons. The neurosecretory junctions with theheart muscle of the American cockroach, Periplaneta americana,show ultrastructural and electrophysiological evidence of chemicallytransmitting synapses, and cytochemical evidence for the presenceof monoamines. Electron microscopy of nerve terminals showsthat synaptic vesicles may be formed directly from electron-dense"neurosecretory" granules Neurotomy of motor axons to skeletal muscles in insects leadsto aggregation and clumping of synaptic vesicles after 48 hours.Treatment of in vitro nerve-muscle preparations with variousrespiratory poisons caused aggregation similar to that developedin neurotomized animals. This suggested that vesicle aggregationin both cases may have resulted from a decrease in availableadenosine triphosphate in the nerve terminal with subsequentalteration in the normal charge density which supports a repulsiveforce between the vesicles.     

Development and characterization of microsatellite DNA primers for ferruginous pygmy‐owls (Glaucidium brasilianum)

Ten polymorphic microsatellite loci were isolated and characterized for the ferruginous pygmy owl (Glaucidium brasilianum). Observed and expected heterozygosity were 0.07–0.85 and 0.1–0.88, respectively. Allele numbers ranged from five to 16 per locus.     

Estimating Duration of Short-Term Acute Effects of Capture Handling and Radiomarking

ABSTRACT Radiotelemetry is used extensively in zoographic studies of wildlife species, including northern bobwhite (Colinus virginianus). These studies assume that radiomarking does not affect survival of marked individuals. However, most researchers implicitly acknowledge that capture, handling, and radiomarking may have short-term deleterious effects on individuals and, therefore, include in analyses only animals that survive an adjustment period of arbitrary length (often 7 days) following capture and marking. Length of adjustment period is rarely empirically based and may potentially bias survival estimates. We outline an analytical approach to determine an appropriate adjustment period and illustrate this approach by examining effects of time-since-marking on survival of 410 northern bobwhite captured during winter from 1997 to 2001, in Mississippi, USA. We modeled daily survival rates using time-since-marking as a covariate in the nest-survival model of Program MARK. Although survival varied among and within years, we found no evidence to suggest that standard adjustment periods of 7–14 days were appropriate for our sample. If adjustment periods are used in radiotelemetry studies, those that are empirically based may be more appropriate than arbitrarily set periods.