Noninvasive assessment of seasonal hormone profile in captive bald eagles (Haliaeetus leucocephalus)

The hypothesis was to test whether a ratio of estrogen:androgen in eagle feces would reflect gonadal activity, and whether our procedure for noninvasive hormone analysis of fecal steroids could be applied to assess seasonal reproductive function in four captive bald eagles (Haliaeetus leucocephalus). Total immunoreactive excretory estrogens (E) and testosterone (T) were analyzed and compared as an E/T ratio from ad libitum monthly stool collections during the 1980–81 breeding season of birds maintained in an artificial insemination (AI) project. Since active male gonads are known to secrete a preponderance of androgens into the peripheral circulation and that renal clearance filters steroid metabolites into the urine, it was reasonable to assume that a lowered excretory E/T profile would mimic major changes in male seasonal steroidogenesis; analogously, active female gonads would result in an increased excretion of urinary estrogens, in turn reflected by a seasonal elevation of E/T ratios. A serial profile of excretory E/T ratio data for two male bald eagles approximated unity values except for a midseason low (x < 0.4) in February, one month prior to semen collections, followed by a significant end-of-breeding season rise in E/T values (x > 2.5, P < 0.01). The average E/T profile from data of two female eagles were two- to sixfold higher than males except for a significant mid-breeding season peak in E/T values during March (x > 13.5, P < 0.01). Despite the absence of nest building or egg production by either female, these preliminary observational data indicated seasonal patterns of gonadal activity in both female eagles that were synchronous with semen availability from adjacent males.     

Genetic variation at enzyme loci in North Atlantic minke whales,Balaenoptera acutorostrata

Electrophoretic variation within and between North Atlantic minke whale samples(Balaenoptera acutorostrata) from West Greenland, Iceland, and Norway was investigated. In the West Greenland samples, 28 enzyme systems were examined, representing 36 loci, of which 6 were found to be polymorphic. In Icelandic and Norwegian samples, 22 enzyme systems were examined, representing 29 loci, of which 6 and 5 were found to be polymorphic, respectively. The average heterozygosity was 0.058 (SE=0.024) in samples from West Greenland, 0.074 (SE=0.028) in samples from Iceland, and 0.054 (SE=0.023) in samples from Norway. No significant deviations from the expected Hardy—Weinberg genotypic frequencies, within samples taken from the same area, were found. Significant differences in allele frequencies were observed, however, between samples from the three different areas. The average Nei's genetic distance was 0.014 and the averageF _st value was 0.126. The genetic differences between the samples from the different areas indicate that those from West Greenland, Iceland, and Norway represented different breeding populations.     

Estimating allowable take for an increasing bald eagle population in the United States

Effectively managing take of wildlife resulting from human activities poses a major challenge for applied conservation. Demographic data essential to decisions regarding take are often expensive to collect and are either not available or based on limited studies for many species. Therefore, modeling approaches that efficiently integrate available information are important to improving the scientific basis for sustainable take thresholds. We used the prescribed take level (PTL) framework to estimate allowable take for bald eagles (Haliaeetus leucocephalus) in the conterminous United States. We developed an integrated population model (IPM) that incorporates multiple sources of information and then use the model output as the scientific basis for components of the PTL framework. Our IPM is structured to identify key parameters needed for the PTL and to quantify uncertainties in those parameters at the scale at which the United States Fish and Wildlife Service manages take. Our IPM indicated that mean survival of birds >1 year old was high and precise (0.91, 95% CI = 0.90–0.92), whereas mean survival of first-year eagles was lower and more variable (0.69, 95% CI = 0.62–0.78). We assumed that density dependence influenced recruitment by affecting the probability of breeding, which was highly imprecise and estimated to have declined from approximately 0.988 (95% CI = 0.985–0.993) to 0.66 (95% CI = 0.34–0.99) between 1994 and 2018. We sampled values from the posterior distributions of the IPM for use in the PTL and estimated that allowable take (e.g., permitted take for energy development, incidental collisions with human made structures, or removal of nests for development) ranged from approximately 12,000 to 20,000 individual eagles depending on risk tolerance and form of density dependence at the scale of the conterminous United States excluding the Southwest. Model-based thresholds for allowable take can be inaccurate if the assumptions of the underlying framework are not met, if the influence of permitted take is under-estimated, or if undetected population declines occur from other sources. Continued monitoring and use of the IPM and PTL frameworks to identify key uncertainties in bald eagle population dynamics and management of allowable take can mitigate this potential bias, especially where improved information could reduce the risk of permitting non-sustainable take.     

Further genetic variation at the esterase loci of Drosophila virilis

Reexamination of the electrophoretic mobilities of esterases encoded by the Est- and the Est- alleles of Drosophila virilis was carried out in detail using both thin-layer agar gel and polyacrylamide slab gel electrophoresis. Many allelic products with fine differences in their electrophoretic mobilities were found and designated by a new system. Some esterases separable by the agar gel method were indistinguishable using the polyacrylamide gel method. But the polyacrylamide gel method uncovered two multiband homozygotes, ^(d).77 and ^(d)1.28. Some allelic frequencies on the basis of the new designation were estimated in two natural populations. As a result, it is proposed that the total scope of allelic variation at the two esterase loci of Drosophila virilis is composed of discrete distribution patterns of gene frequencies, each histogram of which shows a bell-shaped pattern.     

Patterns of genetic variation of the genusCapsicum (Solanaceae) in Mexico

The evolutionary relationships of 186 accessions ofCapsicum from Mexico were studied through enzyme electrophoresis. A total of 76 alleles representing 20 genetic loci coding for nine enzyme systems were observed and the allelic variations of enzymes were studied for geographical distribution. Allele frequencies were used to estimate the apportionment of gene diversity within and between populations and to construct a dendrogram based on a similarity matrix containingNei genetic distances. — The gene diversity estimates suggest that the structure ofCapsicum populations in Mexico consists of predominantly homozygous genotypes presumably due to a self-pollinated breeding system and population bottlenecks. Significant genetic differentiation was found mainly between populations of differing geographical regions.—Based on the results of this study, three species of domesticatedCapsicum can be identified in Mexico,C. annuum var.annuum, C. chinense, andC. pubescens. Semidomesticated and wild forms include two species,C. frutescens andC. annuum var.glabriusculum. A sharp geographical division results between the latter species;C. frutescens was collected exclusively in the southeastern states of Oaxaca, Chiapas, and Tabasco; whereas wild and semidomesticated forms from the rest of the country areC. annuum. Based upon the similarity of enzyme genotypes of semidomesticated and wild forms, the primary center of domestication of cultivatedC. annuum was estimated to be the region comprising the states of Tamaulipas, Nuevo Leon, San Luis Potosi, Veracruz, and Hidalgo in eastern Mexico. A possible second center of domestication is suggested to be localized in the state of Nayarit, western Mexico.     

Lead poisoning and heavy metal exposure of golden eagles ( Aquila chrysaetos ) from the European Alps

Lead poisoning and organ levels of the non-essential heavy metals lead, cadmium and mercury of seven free-ranging golden eagles (Aquila chrysaetos) from the European Alps, and of one 23-year-old captive golden eagle are reported. All birds were found dead or moribund during the years 2000 and 2001 in Austria, Germany and Switzerland. One golden eagle from Switzerland with extraordinarily high lead residues in its liver and kidney was clearly identified as lethally lead poisoned. Another bird from the same region was found still alive and died in a wildlife rehabilitation center, showing lead residues in its organs known for acute lead poisoning with detrimental physiological effects, such as nervous disorders and the inhibition of the hemoglobine synthesis. Concentrations of cadmium, mercury and lead residues in the organs of the other five free-ranging birds, and in the long-lived captive golden eagle, were low and represent the natural background levels in birds of prey of the terrestrial food web. This is the first published report of lead poisoning in golden eagles from Switzerland. Sources for lead poisoning in golden eagles in the Alpine region are discussed.     

Origin and genetic structure of white-tailed sea eagles (<Emphasis Type="Italic">Haliaeetus albicilla</Emphasis>) in the Czech Republic: an analysis of breeding distribution,ringing data and DNA microsatellites

The population of white-tailed sea eagles (Haliaeetus albicilla) in the Czech Republic declined dramatically during the twentieth century. None were observed in the area for more than 60 years until population recoveries were observed beginning in the 1980s. It is currently estimated that 25–30 breeding pairs of white-tailed sea eagles nest in the Czech Republic. This article analyses surveillance data from three periods between 1973 and 2003 on the occurrence and nesting of white-tailed sea eagles in the Czech Republic. We investigated recolonization of European white-tailed sea eagles in the Czech Republic in terms of migration patterns and population structures. Bird ringing data suggest the Czech population may be recovered from various areas encompassing northern Europe. Using data collected by DNA microsatellite, no population structure was revealed through Bayesian and cluster analyses with an existing Hardy–Weinberg equilibrium, which suggests mixed panmictic populations of white-tailed sea eagles in the Czech Republic and Slovakia. While analysis of genetic diversity showed no difference between recovered populations in the southeastern Czech Republic and those persisting in Slovakia, there was genetic diversity between eagles of the southeastern subpopulation and eagles in other parts of the Czech Republic. Taken together, these observations on the population structure of white-tailed sea eagles in the Czech Republic imply that other European birds contributed to the recovery of the Czech population, likely through breeding mixture with an identifiable centre in the southeastern Czech Republic.     

Analysis of genetic stability at SSR loci during somatic embryogenesis in maritime pine (Pinus pinaster)

Somatic embryogenesis (SE) is a propagation tool of particular interest for accelerating the deployment of new high-performance planting stock in multivarietal forestry. However, genetic conformity in in vitro propagated plants should be assessed as early as possible, especially in long-living trees such as conifers. The main objective of this work was to study such conformity based on genetic stability at simple sequence repeat (SSR) loci during somatic embryogenesis in maritime pine (Pinus pinaster Ait.). Embryogenic cell lines (ECLs) subjected to tissue proliferation during 6, 14 or 22 months, as well as emblings regenerated from several ECLs, were analyzed. Genetic variation at seven SSR loci was detected in ECLs under proliferation conditions for all time points, and in 5 out of 52 emblings recovered from somatic embryos. Three of these five emblings showed an abnormal phenotype consisting mainly of plagiotropism and loss of apical dominance. Despite the variation found in somatic embryogenesis-derived plant material, no correlation was established between genetic stability at the analyzed loci and abnormal embling phenotype, present in 64% of the emblings. The use of microsatellites in this work was efficient for monitoring mutation events during the somatic embryogenesis in P. pinaster. These molecular markers should be useful in the implementation of new breeding and deployment strategies for improved trees using SE.     

Isolation of 22 new Haliaeetus microsatellite loci and their characterization in the critically endangered Madagascar fish‐eagle (Haliaeetus vociferoides) and three other Haliaeetus eagle species

We isolated a total of 22 microsatellite loci from two Haliaeetus species: the Madagascar fish‐eagle (Haliaeetus vociferoides) and the bald eagle (Haliaeetus leucocephalus). Five loci were monomorphic in both the Madagascar fish‐eagle (n = 24–43) and the bald eagle (n = 2–8) but were found to be polymorphic in other Haliaeetus species. Haliaeetus loci have proved useful for investigating gene flow in Haliaeetus and Aquila eagles. Ten loci were polymorphic in the critically endangered Madagascar fish‐eagle and will be used to investigate the genetic population structure and mating system in this species.     

An AFLP-based survey of genetic diversity among accessions of sea oats (Uniola paniculata, Poaceae) from the southeastern Atlantic and Gulf coast states of the United States

Uniola paniculata, commonly known as sea oats, is a C₄ perennial grass capable of stabilizing sand dunes. It is most abundant along the Gulf of Mexico and southeastern Atlantic coastal regions of the United States. The species exhibits low seed set and low rates of germination and seedling emergence, and so extensive clonal reproduction is achieved through production of rhizomes, which may contribute to a decline in genetic diversity. To date, there has been no systematic assessment of genetic variability and population structure in naturally occurring stands in the USA. This study was conducted to assess the genetic relationship and diversity among nineteen U. paniculata accessions representing eight states: Texas, Louisiana, Mississippi, Alabama, Florida, South Carolina, North Carolina, and Virginia, using amplified fragment length polymorphism (AFLP). Twelve AFLP EcoRI+MseI primer combinations generated a wide range of polymorphisms (42–81%) with a mean of 59%. Overall, the sea oats plants exhibited a low range of genetic similarity. Florida accessions, FL-33 and FL-39, were most genetically diverse and the accessions from both Carolinas and Virginia (NC-1, NC-11, SC-15, and VA-53) harbored less genetic variability. Cluster analysis using the UPGMA approach separated U. paniculata plants into four major clusters which were also confirmed by principal coordinate analysis (PCO). Further examination of the different components of genetic variation by analysis of molecular variance (AMOVA) indicated the largest proportion of variability at the state level (47.8%) followed by the variation due to the differences among the genotypes within an accession (34.4%), and the differences among the accessions within a state (17.8%). The relationship between genetic diversity and geographic source of sea oats populations of the United States as revealed through this comprehensive study will be helpful to resource managers and commercial nurseries in identifying suitable plant materials for restoration of new areas without compromising the adaptation and genetic diversity.     

Geographic variation in the garter snakes (Thamnophis sirtalis) of the north-central United States, a multivariate study

A study of geographic variation in three subspecies of garter snake (Thamnophis sirtalis sirtalis, T. s. parietalis, T. s. semifasciata) in the north-central United States indicates patterns of irregular non-clinal microgeographic variation for 40 characters of coloration, scalation, and internal anatomy. Multivariate analyses show that geographically close populations are not always phenetically close and that overall differentiation of the phenotype is greater in males than in females. Univariate and multivariate studies indicate that T. s. semifasciata Cope 1892, restricted to the Chicago area, is not uniform within its small range and that it has no constant distinguishing features: it is shown to be taxonomically invalid.     

Isolation and characterization of SNP variation at 90 anonymous loci in the banded wren (<Emphasis Type="Italic">Thryothorus pleurostictus)</Emphasis>

Single nucleotide polymorphisms (SNPs) are becoming more commonly used as molecular markers in conservation studies. However, relatively few studies have employed SNPs for species with little or no existing sequence data, partly due to the practical challenge of locating appropriate SNP loci in these species. Here we describe an application of SNP discovery via shotgun cloning that requires no pre-existing sequence data and is readily applied to all taxa. Using this method, we isolated, cloned and screened for SNP variation at 90 anonymous sequence loci (51 kb total) from the banded wren (Thryothorus pleurostictus), a Central American species with minimal pre-existing sequence data and a documented paucity of microsatellite allelic variation. We identified 168 SNPs (a mean of one SNP/305 bp, with SNPs unevenly distributed across loci). Further characterization of variation at 41 of these SNP loci among 256 individuals including 37 parent–offspring families suggests that they provide substantial information for defining the genetic mating system of this species, and that SNPs may be generally useful for this purpose when other markers are problematic.     

美国西部不同地区Grayia spinosa核DNA ITS序列分析

藜科植物Grayia spinosa是美国西部地区的特有种,多生长在干旱盐碱地,具有重要的生态价值。该研究测定了采自美国西部犹他州G.spinosa的nrDNA ITS序列,与Gen Bank中已提交的G.spinosa的所有ITS序列以及G.spinosa的四个近缘种作为外类群进行比较,分析了美国西部不同地区G.spinosa ITS序列的一级结构与其RNA二级结构的变异规律。结果表明:所有G.spinosa样品的nrDNA ITS序列长度在611~623 bp之间,GC含量在60.35%~61.0%之间,序列间共存在22个变异位点,5个为简约信息位点。各样品间的遗传距离在0.001 8~0.008 9之间,不同样品间的遗传距离与地理距离的相关性不显著。邻接法构建的系统发育树显示所有G.spinosa聚为一大支,与外类群形成明显分支。此外,利用RNAfold在线软件预测了G.spinosa ITS序列的RNA二级结构,将8个G.spinosa样品的RNA二级结构根据构型差异大体上分为四类,分别记为type A,B,C和D四类,主要变异出现在ITS1和ITS2区。所不同的是在G.spinosa ITS的一级结构分析中GSNE1与GSWA8体现出更近的亲缘关系,但二者的RNA二级结构差异明显,同时GSNE2、GSUT3、GSUT4、GSCA5、GSCA6、GSCO7在ITS序列一级结构分析中也体现出较近的亲缘关系,但是他们的RNA二级结构差异明显。这可能与ITS序列的RNA二级结构在进化中体现出更大的保守性有关。     

Inter- and intrapopulation genetic variation in species ofPorphyra (Rhodophyta: Bangiales) from British Columbia and adjacent waters

Starch gel electrophoresis of 17 proteins has provided data on inter- and intrapopulation genetic variation in 20 species ofPorphyra occurring in British Columbia and adjacent areas.P. cuneiformis andP. nereocystis showed no within species variation, even over ranges of more than 1000 km. Populations ofP. abbottae, P. fallax, P. fucicola, P. gardneri andP. schizophylla were characterized by fixation for certain alleles. The number of polymorphic loci in a population ranged from zero to nine, depending on the species. Six species had populations that were polymorphic at just a single locus. Only two species (P. mumfordii andP. pseudolanceolata) had populations that were polymorphic at more than three loci. These levels of genetic variation are lower than those reported for populations of JapanesePorphyra species. Eleven taxa were polymorphic for 6-phosphogluconate dehydrogenase, the most variable enzyme. No within species polymorphisms were detected for bromoperoxidase, lactate dehydrogenase, superoxide dismutase or phycoerythrin. Possible evidence for the chimeric nature of the thallus was observed only inP. mumfordii.     

Comparisons of within-population genetic variation in sexual and agamospermousAmelanchier (Rosaceae) using RAPD markers

We compared genetic variation of sexualAmelanchier bartramiana and facultatively agamospermous (asexually seed-producing)A. laevis at one site where the two species are sympatric. We analyzed 77 random amplified polymorphic DNA (RAPD) markers in 29A. bartramiana individuals and 76 RAPD markers in 31A. laevis individuals. The two species do not differ significantly in mean genetic variation. However, 22.4% of genetic similarity values betweenA. laevis individuals exceed the highest value ofA. bartramiana and may represent the effect of agamospermy. Variation withinA. laevis may be the result of sexuality, hybridization, polyploidy, and other factors.     

Constraints on geographic variation in fiddler crabs (Ocypodidae: Uca) from the western Atlantic

A key question in evolutionary biology is how intraspecific variation biases the evolution of a population and its divergence from other populations. Such constraints potentially limit the extent to which populations respond to selection, but may endure long enough to have macroevolutionary consequences. Previous studies have focused on the association between covariation patterns and divergence among isolated populations. Few have focused on geographic variation among semi‐connected populations, however, even though this may be indicative of early selective pressures that could lead to long‐term divergence and speciation. Here, we test whether covariation in the shape of the carapace of fiddler crabs (genus Uca Leach, 1814) is important for structuring geographic variation. We find that morphological divergence among populations is associated with evolvability in the direction of divergence in only a few species. The shape of the ancestral covariation matrix in these species differs from other species in having notably more variation concentrated along fewer directions (i.e. higher eccentricity). For most species, there is some evidence that covariation has constrained the range of directions into which populations have diverged but not the degree of divergence. These results suggest that even though fiddler crab populations have diverged morphologically in directions predicted by covariation, constraints on the extent to which divergence has occurred may only be manifested in species where variation patterns are eccentric enough to limit populations’ ability to respond effectively in many directions.     

Geographical variation and genetic analysis of leaf shape inCrepis tectorum (Asteraceae)

Canonical variate analysis of plants raised in a uniform environment was used to study the pattern of geographical variation in leaf shape ofCrepis tectorum (Asteraceae). The diversity in leaf shape was much greater among populations confined to areas with exposed bedrock in the Baltic region than among weed populations scattered throughout Europe and Canada. A Ward's clustering linked outcrop populations from the archipelago of SW. Finland and the islands of Öland (Sweden) and Saaremaa (Estonia) due to the deeply lobed leaves characterizing these populations, while outcrop populations along the coast of E. Sweden were grouped due to their weakly lobed, narrow and dentate leaves. Most of the weed populations were grouped together but there was no tendency for the variation in this group to be related to habitat or geographical location. A mosaic of variation reflected in sharp (random) differentiation among local populations was superimposed on the large-scale ecogeographical pattern.—Crossing data indicated that most of the variation in degree of leaf dissection is governed by one major gene with deeply lobed leaves dominant over weakly lobed leaves. I suggest that the simple pattern of inheritance may have favoured rapid evolutionary changes in leaf shape, particularly in the Baltic area which emerged relatively late from the sea. Genetic correlations may have constrained the pattern of variation at higher taxonomic levels, since some of the trait associations detected in a segregating F₂ generation were also found at the among-population level.     

Enzyme analysis of genetic variation and relationships in diploid and polyploid taxa ofGalium (Rubiaceae)

Allozyme variation at 11 loci (with 37 alleles) was studied electrophoretically in seven outbreeding, closely related diploid and tetraploid taxa, seven from sect.Leptogalium and two from sect.Leiogalium. Whereas the sections are clearly distinct by several different alleles, aggregates, species and subspecies differ only in the frequency or presence/absence of common alleles. The resulting dendrogram suggests phylogenetic relationships and is supported by other multidisciplinary evidence. Tetraploids have originated independently in several groups, and there is evidence for tetrasomic inheritance and thus for autopolyploidy in spite of normal meiotic bivalent pairing and partly suspected hybrid origin. Tetraploids differ from related diploids only little in number of alleles and expected heterozygosity within populations, but clearly exhibit higher numbers of genotypes. This often corresponds to their greater morphological variability, increased adaptive flexibility, and better colonizing capacity compared to related diploids.