bluuebunny/crossref_metadata_2025_split huggingface dataset:
Control of body size ofLasius nigerant sexuals — worker interests, genes and environment
Authors: FJERDINGSTAD ELSE J. 
Published: August 2005

AbstractIn most animals, the survival and reproductive success of males and females is linked to their size. The ability of individuals to control environmental influences on size will therefore have consequences for their fitness. In eusocial insects, individual males and reproductive females do not have to forage for themselves or control their local environment. Instead, they are reared by nonreproductive siblings (workers) inside colonies. Workers should benefit from controlling the size of sexuals because these sexuals are usually the only means for workers to transmit their genes to future generations. Nevertheless, considerable intraspecific variation exists around mean sexual size in social hymenopterans, even in species with monomorphic sexuals. This variation could result from genetic influences on sexual size, for instance sexuals may be selected to not agree to worker interests, or be due to strong, unpredictable environmental conditions constraining the efforts of workers to control sexual size. In a study that is the first of its kind I investigated genetic and environmental components of sexual body size variation in the antLasius niger, examining sexuals from wild colonies with one or several fathers (paternity levels established through microsatellite DNA offspring analysis). Evidence was found for a genetic component of size (broad‐sense heritability of up to 42%) but strong common‐colony effects (among‐colony variation in food availability or in worker capacities to restrain sexual selfishness) also increased the size differences among colonies. Workers thus seem to only have partial‐control over sexual size, but may be doing the best of a bad job.
Growth, productivity, and competitiveness of introgressed weedy Brassica rapa hybrids selected for the presence of Bt cry1Ac and gfp transgenes
Authors: HALFHILL MATTHEW D. , SUTHERLAND JAMIE P. , MOON HONG SEOK , POPPY GUY M. , WARWICK SUZANNE I. , WEISSINGER ARTHUR K. , RUFTY THOMAS W. , RAYMER PAUL L. , STEWART C. NEAL 
Published: August 2005

AbstractConcerns exist that transgenic crop × weed hybrid populations will be more vigorous and competitive with crops compared with the parental weed species. Hydroponic, glasshouse, and field experiments were performed to evaluate the effects of introgression of Bacillus thuringiensis (Bt) cry1Ac and green fluorescent protein (GFP) transgenes on hybrid productivity and competitiveness in four experimental Brassica rapa × transgenic Brassica napus hybrid generations (F1, BC1F1, BC2F1 and BC2F2). The average vegetative growth and nitrogen (N) use efficiency of transgenic hybrid generations grown under high N hydroponic conditions were lower than that of the weed parent (Brassica rapa, AA, 2n = 20), but similar to the transgenic crop parent, oilseed rape (Brassica napus, AACC, 2n = 38). No generational differences were detected under low N conditions. In two noncompetitive glasshouse experiments, both transgenic and nontransgenic BC2F2 hybrids had on average less vegetative growth and seed production than B. rapa. In two high intraspecific competition field experiments with varied herbivore pressure, BC2F2 hybrids produced less vegetative dry weight than B. rapa. The competitive ability of transgenic and nontransgenic BC2F2 hybrids against a neighbouring crop species were quantified in competition experiments that assayed wheat (Triticum aestivum) yield reductions under agronomic field conditions. The hybrids were the least competitive with wheat compared with parental Brassica competitors, although differences between transgenic and nontransgenic hybrids varied with location. Hybridization, with or without transgene introgression, resulted in less productive and competitive populations.
Interfamilial characterization of a region of the ZFX and ZFY genes facilitates sex determination in cetaceans and other mammals
Authors: MORIN PHILLIP A. , NESTLER AVIVA , RUBIO‐CISNEROS NADIA T. , ROBERTSON KELLY M. , MESNICK SARAH L. 
Published: August 2005

AbstractSequence polymorphism of homologues ZFX and ZFY, in a 604‐base pair exon region, was examined in 10 known males and 10 known females across seven cetacean families and used to design a simple, highly sensitive and widely applicable fluorescent 5′ exonuclease assay for gender determination in cetaceans. Multiplex amplification, cloning, and sequencing of these previously uncharacterized regions revealed (i) eight fixed differences between ZFX and ZFY, (ii) 29 variable sites between ZFX and ZFY and (iii) very low interspecific nucleotide diversity for both ZFX and ZFY across all families examined. We developed a 5′ exonuclease assay that produces a small (105 bp) polymerase chain reaction (PCR) product from both the X and the Y chromosome orthologs, and used double‐labelled fluorescent probes to distinguish between the two genes in a real‐time PCR assay that is highly reproducible and sensitive. We demonstrated sex specificity for 33 cetacean species in nine families. Given the availability of conserved primers and sequence information for many mammalian species, this approach to designing sexing assays for a wide range of species is both practical and efficient.
Gene expression patterns accompanying a dietary shift in Drosophila melanogaster
Authors: CARSTEN L. D. , WATTS T. , MARKOW T. A. 
Published: August 2005

AbstractThe ability of many organisms to switch to new hosts can be critical to their survival in the wild. However, the genetic mechanisms underlying such shifts are poorly understood. In this study, we used complementary DNA (cDNA) microarrays to ask if changes in gene expression are observed in response to a dietary shift in Drosophila melanogaster, a dietary generalist. We found significant and repeatable differential expression in a number of genes related to metabolic function and stress, suggesting that a functional genomics approach will be useful in seeking loci involved in the ability of flies to utilize different resources.
Migratory charr schools exhibit population and kin associations beyond juvenile stages
Authors: FRASER DYLAN J. , DUCHESNE PIERRE , BERNATCHEZ LOUIS 
Published: August 2005

AbstractFew studies have critically investigated the genetic composition of wild fish schools. Yet, such investigations may have profound implications for the understanding of social organization and population differentiation in both fundamental and applied research. Using 20 microsatellite loci, we investigated the composition of 53 schools (totaln = 211) of adult and subadult migratory brook charr (Salvelinus fontinalis) sampled from the known feeding areas of two populations inhabiting Mistassini Lake (Québec, Canada). We specifically tested whether (i) school members originated from the same population, (ii) individuals from the same population within schools were kin (half‐ or full‐siblings), and (iii) kin schooling relationships differed between sexes. Randomization tests revealed a tendency for most schools to be population specific, although some schools were population mixtures. Significantly more kin were found within schools than expected at random for both populations (≈ 21–34% of the total number of school members). This result, combined with the observed size range of individuals, indicated that stable associations between kin may occur beyond juvenile stages for up to 4 years. Nevertheless, a high proportion of school members were non‐kin (≈ 66–79%). No differences were detected between sexes in the propensity to school with kin. We discuss the hypothesis that the stable kin groups, rather than arising from kin selection, may instead be a by‐product of familiarity based on individual selection for the maintenance of local adaptations related to migration (natal and feeding area philopatry). Our results are noteworthy because they suggest that there is some degree of permanence in the composition of wild fish schools. Additionally, they support the hypothesis that schools can be hierarchically structured (from population members down to family groups) and are thus nonrandom genetic entities.
Marine landscapes and population genetic structure of herring (Clupea harengus L.) in the Baltic Sea
Authors: JØRGENSEN HANNE B. H. , HANSEN MICHAEL M. , BEKKEVOLD DORTE , RUZZANTE DANIEL E. , LOESCHCKE VOLKER 
Published: August 2005

AbstractNumerically small but statistically significant genetic differentiation has been found in many marine fish species despite very large census population sizes and absence of obvious barriers to migrating individuals. Analyses of morphological traits have previously identified local spawning groups of herring (Clupea harengus L.) in the environmentally heterogeneous Baltic Sea, whereas allozyme markers have not revealed differentiation. We analysed variation at nine microsatellite loci in 24 samples of spring‐spawning herring collected at 11 spawning locations throughout the Baltic Sea. Significant temporal differentiation was observed at two locations, which we ascribe to sympatrically spawning but genetically divergent ‘spawning waves’. Significant differentiation was also present on a geographical scale, though pairwise FST values were generally low, not exceeding 0.027. Partial Mantel tests showed no isolation by geographical distance, but significant associations were observed between genetic differentiation and environmental parameters (salinity and surface temperature) (0.001 < P≤ 0.099), though these outcomes were driven mainly by populations in the southwestern Baltic Sea, which also exhibits the steepest environmental gradients. Application of a novel method for detecting barriers to gene flow by combining geographical coordinates and genetic differentiation allowed us to identify two zones of lowered gene flow. These zones were concordant with the separation of the Baltic Sea into major basins, with environmental gradients and with differences in migration behaviour. We suggest that similar use of landscape genetics approaches may increase the understanding of the biological significance of genetic differentiation in other marine fishes.
Phylogeography of pollinator‐specific sexually deceptiveChiloglottistaxa (Orchidaceae): evidence for sympatric divergence?
Authors: MANT J. , BOWER C. C. , WESTON P. H. , PEAKALL R. 
Published: August 2005

AbstractDivergence in sexually deceptive orchids is thought to occur through shifts in the attraction of specific pollinators, a process that is mediated by changes in the floral odours that lure sexually excited male insects. We investigated the origin of reproductive isolation in a sexually deceptive species complex ofChiloglottisR.Br. (Orchidaceae: Diurideae). Two geographically separated montane regions in eastern Australia were sampled, each containing sympatric pairs of orchid taxa presently found under the name,Chiloglottis pluricallata. Behavioural tests confirmed at least three distinct orchid taxa that specifically attract different pollinators. An artificial crossing experiment among two taxa from one region demonstrated their interfertility, and confirmed isolation to be a function of pollinator attraction. A phylogeographic analysis using amplified fragment length polymorphisms (AFLPs) indicated that samples from each geographical region are most closely related, a pattern consistent within situor sympatric divergence. However, an extensive population genetic study on two taxa from one region failed to entirely reject the possibility of intertaxon gene flow. Although clear genetic differentiation of the taxa is evident in two out of three sites where both grow in direct sympatry, overall, the two taxa are not strongly distinguished by AFLP markers. The reconstruction of a simple bifurcating pattern of divergence may be confounded by a combination of contemporary population‐level processes operating within each taxon, the retention of ancestral polymorphism or intertaxon gene flow.
Genetic variation and population structure in remnant populations of black rhinoceros, Diceros bicornis, in Africa
Authors: HARLEY ERIC H. , BAUMGARTEN INGRID , CUNNINGHAM JESSICA , O'RYAN COLLEEN 
Published: August 2005

AbstractBlack rhinoceros (Diceros bicornis) are one of the most endangered mammal species in Africa, with a population decline of more than 96% by the end of the last century. Habitat destruction and encroachment has resulted in fragmentation of the remaining populations. To assist in conservation management, baseline information is provided here on relative genetic diversity and population differentiation among the four remaining recognized subspecies. Using microsatellite data from nine loci and 121 black rhinoceros individuals, and comparing the results with those of other African species affected in similar ways, Diceros bicornis michaeli retained the most genetic diversity (heterozygosity 0.675) compared with Diceros bicornis minor (0.459) and Diceros bicornis bicornis (0.505), suggesting that the duration of the known bottlenecks in these populations has only had a limited impact on diversity. Comparable and moderate degrees of population differentiation were found between D. b. minor, D. b. bicornis and D. b. michaeli. Results from the single sample available of the most endangered subspecies, Diceros bicornis longipes, showed the least diversity of all individuals examined. This information should assist conservation management decisions, especially those affecting population viability assessments and selection of individuals for translocations, and will also facilitate subspecies identification for ex situ individuals of uncertain origin.
Age‐specific mating strategies and reproductive senescence
Authors: RICHARD M. , LECOMTE J. , DE FRAIPONT M. , CLOBERT J. 
Published: August 2005

AbstractWhile males gain obvious direct advantages from multiple mating, the reproductive capacity of females is more constrained. The reason why polyandry evolved in females is therefore open to many conjectures. One hypothesis postulates that females gain indirect benefits by increasing the probability of siring young from high quality males. To explore this hypothesis, we used the natural variation of the reproductive value that males and females undergo through age. The age‐related variation of phenotypic performance might then induce variations in mating strategies in males and females. Using the common lizard (Lacerta vivipara) as our model system, we showed that reproductive immaturity and senescence created variability in both male and female reproductive success (including survival of offspring). Consistent with theory, males at their best‐performing phenotype adopted a polygynous strategy. These males were of an intermediate age and they produced offspring of higher viability than younger and older males. In contrast, females at their best performing phenotype, also of an intermediate age, were less polyandrous than other less‐ performing females. Middle‐aged females tended to mate with males of an intermediate age and produced litters with higher viability independently from their reproductive strategy. Males of an intermediate age enhanced their fitness by additional matings with young or old females. Young and old females increased their fitness by being more polyandrous. Polyandry therefore appears as means to seek for good males. A positive correlation between males and their partners’ fitness disagree with the idea that polyandry is the result of a sexual conflict in this species.
Mitochondrial DNA phylogeography of the Mesoamerican spiny‐tailed lizards (Ctenosaura quinquecarinatacomplex): historical biogeography, species status and conservation
Authors: HASBÚN CARLOS ROBERTO , GÓMEZ AFRICA , KÖHLER GUNTHER , LUNT DAVID H. 
Published: August 2005

AbstractThrough the examination of past and present distributions of plants and animals, historical biogeographers have provided many insights on the dynamics of the massive organismal exchange between North and South America. However, relatively few phylogeographic studies have been attempted in the land bridge of Mesoamerica despite its importance to better understand the evolutionary forces influencing this biodiversity ‘hotspot’. Here we use mitochondrial DNA sequence data from fresh samples and formalin‐fixed museum specimens to investigate the genetic and biogeographic diversity of the threatened Mesoamerican spiny‐tailed lizards of theCtenosaura quinquecarinatacomplex. Species boundaries and their phylogeographic patterns are examined to better understand their disjunct distribution. Three monophyletic, allopatric lineages are established using mtDNA phylogenetic and nested clade analyses in (i) northern: México, (ii) central: Guatemala, El Salvador and Honduras, and (iii) southern: Nicaragua and Costa Rica. The average sequence divergence observed between lineages varied between 2.0% and 3.7% indicating that they do not represent a very recent split and the patterns of divergence support the recently established nomenclature ofC. quinquecarinata,Ctenosaura flavidorsalisandCtenosaura oaxacana. Considering the geological history of Mesoamerica and the observed phylogeographic patterns of these lizards, major evolutionary episodes of their radiation in Mesoamerica are postulated and are indicative of the regions’ geological complexity. The implications of these findings for the historical biogeography, taxonomy and conservation of these lizards are discussed.
Multilocus estimation of pairwise relatedness with dominant markers
Authors: RITLAND KERMIT 
Published: August 2005

AbstractEstimators for pairwise relatedness designed for dominant markers are derived, based on a genetic model that accounts for the full structure of pairwise relatedness between two individuals at a diploid locus with dominance. They jointly estimate ‘relatedness’ and ‘fraternity’, in which case the estimators are inherently multilocus, as at least two loci of differing gene frequency are required. Extensions to cases of zero fraternity and isolation by distance (inbreeding) are also examined. Properties of estimators are examined by simulation and compared to the estimator of Hardy. The most statistical power for pairwise relatedness occurs when roughly half of individuals are the recessive phenotype. Estimation procedures are implemented in the computer program mark.
Use of doramectin for treatment of sarcoptic mange in five Angora rabbits
Authors: VOYVODA HUSEYIN , ULUTAS BULENT , EREN HASAN , KARAGENC TULIN , BAYRAMLI GOKSEL 
Published: August 2005

Abstract  The efficacy of administering doramectin after moxidectin treatment, which has previously proved only partially effective, was evaluated in five Angora rabbits naturally infested with Sarcoptes scabiei mange. Evaluations included physical examination for clinical signs of sarcoptic mange and collection of skin scrapings for determination of mites. The rabbits first received two subcutaneous injections, 10 days apart, of moxidectin 1% injectable solution at a dosage of 0.2 mg kg−1 of bodyweight. Although moxidectin treatment resulted in clinical improvement within 10 days post initial injection, on days 10 and 35 post initial treatment live mites were present in skin scrapings. Administration of doramectin 1% injectable solution using the same route and dosage and at similar intervals to moxidectin led to complete disappearance of signs of scabies and parasitological cure in all rabbits.
Bilateral ear canal neoplasia in three dogs
Authors: ZUR GILA 
Published: August 2005

Abstract Bilateral ear canal infections are common in dogs. Ear canal neoplasia is usually associated with unilateral problems, and is uncommon in dogs. To the best of the author's knowledge, bilateral aural neoplasia has not been reported in dogs, and only four case reports were found in the human literature. This report presents three dogs that had bilateral tumours in their ear canals. They were presented with bilateral otitis externa. All three dogs exhibited tissue proliferation of both ear canals that did not respond to glucocorticoids. Treatment consisted of total ear canal ablation, and tissues were submitted for histopathological evaluation. Case # 1 (a 10‐year‐old, male cocker spaniel) was diagnosed as ceruminious gland carcinoma. Cases # 2 and 3 were diagnosed as squamous cell carcinoma. Case # 1 was diagnosed 4 years earlier as having keratinization disorder, which was causing its chronic ear problems. Case # 2 (a 5‐year‐old, female French bulldog) was diagnosed 4 years earlier as having atopic dermatitis, which did not respond to hyposensitization, and only partially responded to glucocorticoids therapy. Case # 3 (a 9‐year‐old, male German shepherd) was diagnosed by the referring veterinarian as having unilateral ear canal proliferation 2 months prior to presentation. However, otoscopic examination showed bilateral proliferation that obstructed both canals. In summary, bilateral ear canal neoplasia should be considered in cases of nonresponsive, proliferative aural pathology.
Zinc‐responsive dermatosis in goats suggestive of hereditary malabsorption: two field cases
Authors: KRAMETTER‐FROETSCHER REINHILD , HAUSER SIMONE , BAUMGARTNER WALTER 
Published: August 2005

Abstract Two cases of zinc deficiency in dairy goats from different flocks and not associated with a zinc‐deficient diet are described. Hard, dry, hyperkeratotic skin, hair loss and pruritus especially prominent on the back, legs, udder, face and ears were the most common clinical signs. Skin biopsy findings revealed a mixture of orthokeratotic and parakeratotic hyperkeratosis. On initial examination, serum zinc concentrations were low in both goats (461 µg L−1and 521 µg L−1, respectively). Although mild skin lesions persisted during the early stages of zinc supplementation, skin lesions completely resolved after prolonged oral zinc supplementation. Withdrawal of zinc supplementation resulted in re‐appearance of lesions in both animals. Case 2 gave birth to two kids, one of which showed mild skin lesions at 8 months of age together with a low serum zinc concentration (434 µg L−1), suggestive of hereditary zinc malabsorption. The other kid remained free of skin lesions and had a serum zinc concentration (530 µg L−1) within the normal range. On the basis of historical and clinical findings, the cases presented here more closely resemble Syndrome 1 hereditary zinc deficiency as seen in Nordic dog breeds rather than other zinc deficiency conditions seen in other species. It is suggested that zinc deficiency in these goats was due to hereditary malabsorption of dietary zinc. This is the first descriptive study of this condition in goats. Life‐long zinc supplementation may be necessary in such patients.