bluuebunny/crossref_metadata_2025_split huggingface dataset:
Substantial genetic substructuring in southeastern and alpine Australia revealed by molecular phylogeography of the Egernia whitii (Lacertilia: Scincidae) species group
Authors: CHAPPLE DAVID G. , KEOGH J. SCOTT , HUTCHINSON MARK N. 
Published: April 2005

AbstractPalaeoclimatic events and biogeographical processes since the mid‐Tertiary are believed to have strongly influenced the evolution and distribution of the terrestrial vertebrate fauna of southeastern Australia. We examined the phylogeography of the temperate‐adapted members of the Egernia whitii species group, a group of skinks that comprise both widespread low‐ to mid‐elevation (E. whitii) and montane‐restricted species (Egernia guthega, Egernia montana), in order to obtain important insights into the influence of past biogeographical processes on the herpetofauna of southeastern Australia. Sequence data were obtained from all six temperate‐adapted species within the E. whitii species group, and specifically from across the distributional ranges of E. whitii, E. guthega and E. montana. We targeted a fragment of the ND4 mitochondrial gene (696 bp) and analysed the data using maximum likelihood and Bayesian methods. Our data reveal a deep phylogeographical break in the east Gippsland region of Victoria between ‘northern’ (Queensland, New South Wales, Australian Capital Territory) and ‘southern’ (Victoria, Tasmania, South Australia) populations of E. whitii. This divergence appears to have occurred during the late Miocene–Pliocene, with the Gippsland basin possibly forming a geographical barrier to dispersal. Substantial structuring within both the ‘northern’ and the ‘southern’ clades is consistent with the effects of Plio–Pleistocene glacial‐interglacial cycles. Pleistocene glacial cycles also appear to have shaped the phylogeographical patterns observed in the alpine species, E. guthega and E. montana. We used our results to examine the biogeographical process that led to the origin and subsequent diversification of the lowland and alpine herpetofauna of southeastern Australia.
Regionally isolated populations of an imperiled Caribbean coral,Acropora palmata
Authors: BAUMS ILIANA B. , MILLER MARGARET W. , HELLBERG MICHAEL E. 
Published: April 2005

AbstractThe movements of larvae between marine populations are difficult to follow directly and have been the subject of much controversy, especially in the Caribbean. The debate centres on the degree to which populations are demographically open, such that depleted populations can be replenished by recruitment from distant healthy populations, or demographically closed and thus in need of local management. Given the depressed state of many tropical reef populations, the understanding of these movements now bears critically on the number, placement, and size of marine reserves. Most genetic analyses assume that dispersal patterns have been stable for thousands of generations, thus they commonly reflect past colonization histories more than ongoing dispersal. Recently developed multilocus genotyping approaches, however, have the demonstrated ability to detect both migration and population isolation over far shorter timescales. Previously, we developed five microsatellite markers and demonstrated them to be both Mendelian and coral‐specific. Using these markers and Bayesian analyses, we show here that populations of the imperiled reef‐building coral,Acropora palmata, have experienced little or no recent genetic exchange between the western and the eastern Caribbean. Puerto Rico is identified as an area of mixing between the two subregions. As a consequence of this regional isolation, populations in the western and eastern Caribbean should have the potential to adapt to local conditions and will require population‐specific management strategies.
Low level of gene flow from cultivated beets (Beta vulgaris L. ssp. vulgaris) into Danish populations of sea beet (Beta vulgaris L. ssp. maritima (L.) Arcangeli)
Authors: ANDERSEN N. S. , SIEGISMUND H. R. , MEYER V. , JØRGENSEN R. B. 
Published: April 2005

AbstractGene flow from sugar beets to sea beets occurs in the seed propagation areas in southern Europe. Some seed propagation also takes place in Denmark, but here the crop–wild gene flow has not been investigated. Hence, we studied gene flow to sea beet populations from sugar beet lines used in Danish seed propagation areas. A set of 12 Danish, two Swedish, one French, one Italian, one Dutch, and one Irish populations of sea beets, and four lines of sugar beet were analysed. To evaluate the genetic variation and gene flow, eight microsatellite loci were screened. This analysis revealed hybridization with cultivated beet in one of the sea beet populations from the centre of the Danish seed propagation area. Triploid hybrids found in this population were verified with flow cytometry. Possible hybrids or introgressed plants were also found in the French and Italian populations. However, individual assignment test using a Bayesian method provided 100% assignment success of diploid individuals into their correct subspecies of origin, and a Bayesian Markov chain Monte Carlo (MC MC) approach revealed clear distinction of individuals into groups according to their subspecies of origin, with a zero level of genetic admixture among subspecies. This underlines that introgression beyond the first hybridization is not extensive. The overall pattern of genetic distance and structure showed that Danish and Swedish sea beet populations were closely related to each other, and they are both more closely related to the population from Ireland than to the populations from France, the Netherlands, and Italy.
Phylogeographic structure and postglacial evolutionary history of water voles (Arvicola terrestris) in the United Kingdom
Authors: PIERTNEY STUART B. , STEWART WENDY A. , LAMBIN XAVIER , TELFER SANDRA , AARS JON , DALLAS JOHN F. 
Published: April 2005

AbstractThe phylogeographic pattern of mitochondrial DNA variation in water voles (Arvicola terrestris) from 57 localities across the United Kingdom and representative samples from Spain, France, Switzerland and Finland was determined from sequence variation in the central portion of the control region. Twenty‐seven different haplotypes were resolved which formed two distinct phylogenetic clades. This major division separated haplotypes found in Scotland from those found in England and Wales. Nested clade analysis of haplotypes indicated that such a division was a consequence of allopatric fragmentation. The haplotypes found in Switzerland, France and Spain clustered with Scottish haplotypes, whereas the haplotype from Finland clustered with the English/Welsh haplotypes. These patterns indicate that contemporary Scottish populations are derived from an Iberian glacial refugium, whereas English and Welsh populations are derived from an eastern European refugium. As such, the postglacial recolonization of the United Kingdom must have involved two colonization events, either in different localities with no subsequent contact, or as two waves separated over time, with the second wave of colonizers displacing the first. An analysis of molecular variance (amova) identified significant population genetic divergence within both the major clades, indicative of restricted gene flow and regional population isolation. The implications of both phylogeographical and population genetic structure are discussed in context with the conservation of water voles in Britain.
Social parasitism in fire ants (Solenopsis spp.): a potential mechanism for interspecies transfer of Wolbachia
Authors: DEDEINE FRANCK , AHRENS MICHAEL , CALCATERRA LUIS , SHOEMAKER D. DEWAYNE 
Published: April 2005

AbstractOne possible mechanism for interspecific transfer of Wolbachia is through the intimate contact between parasites and their hosts. We surveyed 10 species of fly parasitoids (Pseudacteon spp.) and one inquiline social parasite, Solenopsis daguerrei, for the presence and sequence identity (wsp gene) of Wolbachia. Two Wolbachia variants infecting S. daguerrei were identical to known variants infecting the two common ant host species, Solenopsis invicta and Solenopsis richteri, suggesting possible transfers of Wolbachia between this parasite and their hosts have occurred. Our data also revealed an unexpectedly high diversity of Wolbachia variants within S. daguerrei: up to eight variants were found within each individual, which, to our knowledge, is the highest reported number of Wolbachia variants infecting a single individual of any host species.
Nonequilibrium conditions following landscape rearrangement: the relative contribution of past and current hydrological landscapes on the genetic structure of a stream‐dwelling fish
Authors: POISSANT JOCELYN , KNIGHT THOMAS W. , FERGUSON MOIRA M. 
Published: April 2005

AbstractInterpreting patterns of population structure in nature is often challenging, especially in dynamic landscapes where population genetic connectivity evolves over time. In this study, we document the absence of migration‐drift equilibrium in a stream‐dwelling euryhaline fish resulting from past fine‐scale drainage rearrangements and evaluate the relative contribution of past and current hydrological landscapes on observed population structure. Based on allelic variation at nine microsatellite loci, genetic relationships among 12 populations of brook charr, Salvelinus fontinalis, from Gros Morne National Park of Canada (GMNP, Newfoundland, Canada) did not reflect current stream hierarchical structure. In addition, we observed no correlation between population differentiation and contemporary landscape features (waterway distance and sums of altitudinal differences). Instead, population relationships were consistent with historical hydrological structure predicted a priori based on geomorphological and biogeographical evidences. Also, population differentiation was strongly correlated with inferred historical landscape features. Contemporary barriers have apparently preserved the signature of past genetic connectivity by constraining gene flow. Based on the relationships between population differentiation and current and past landscape features at various spatial scales, we suggest that brook charr genetic diversity in GMNP is mostly the result of small distance migrations at the time of colonization and subsequent differentiation through drift. This study highlights the potential of approaching landscapes from a combination of contemporary and historical perspectives when interpreting nonequilibrium population structures resulting from landscape rearrangement.
Chloroplast microsatellites: measures of genetic diversity and the effect of homoplasy
Authors: NAVASCUÉS M. , EMERSON B. C. 
Published: April 2005

AbstractChloroplast microsatellites have been widely used in population genetic studies of conifers in recent years. However, their haplotype configurations suggest that they could have high levels of homoplasy, thus limiting the power of these molecular markers. A coalescent‐based computer simulation was used to explore the influence of homoplasy on measures of genetic diversity based on chloroplast microsatellites. The conditions of the simulation were defined to fit isolated populations originating from the colonization of one single haplotype into an area left available after a glacial retreat. Simulated data were compared with empirical data available from the literature for a species ofPinusthat has expanded north after the Last Glacial Maximum. In the evaluation of genetic diversity, homoplasy was found to have little influence on Nei's unbiased haplotype diversity (HE) while Goldstein's genetic distance estimates () were much more affected. The effect of the number of chloroplast microsatellite loci for evaluation of genetic diversity is also discussed.
Unrelated queens coexist in colonies of the termite Macrotermes michaelseni
Authors: HACKER M. , KAIB M. , BAGINE R. K. N. , EPPLEN J. T. , BRANDL R. 
Published: April 2005

AbstractRelatedness increases the likelihood of cooperation within colonies of social insects. Polygyny, the coexistence of numerous reproductive females (queens) in a colony, is common in mature colonies of the termite Macrotermes michaelseni. In this species, polygyny results from pleometrosis and from several female alates that jointly found a new colony. To explain this phenomenon, it was suggested that only related females cooperate and survive during maturation of colonies. Using multilocus fingerprints as well as microsatellites, we showed that nestmate queens in mature colonies are unrelated. Furthermore, we found that all nestmate queens contributed to the production of steriles. Even in mature colonies, several matrilines of steriles coexist within a colony. Although genetic diversity within colonies may increase the likelihood of conflicts, high genetic diversity may be important for foraging, colony growth, and resistance to disease and parasites.
Genetic structure and history of populations of the deep‐sea fish Helicolenus dactylopterus (Delaroche, 1809) inferred from mtDNA sequence analysis
Authors: ABOIM M. A. , MENEZES G. M. , SCHLITT T. , ROGERS A. D. 
Published: April 2005

Abstract Helicolenus dactylopterus is an Atlantic benthopelagic fish species inhabiting high‐energy habitats on continental slopes, seamounts and islands. Partial sequences of the mitochondrial control region (D‐loop) and cytochrome b (cyt b) were used to test the hypothesis that H. dactylopterus disperses between continental margin, island and seamount habitats on intraregional, regional and oceanic scales in the North Atlantic. Individuals were collected from five different geographical areas: Azores, Madeira, Portugal (Peniche), Cape Verde and the northwest Atlantic. D‐loop (415 bp) and cyt b (423 bp) regions were partially sequenced for 208 and 212 individuals, respectively. Analysis of variation among mitochondrial DNA sequences based on pairwise F‐statistics and amova demonstrated marked genetic differentiation between populations in different geographical regions specifically the Mid‐Atlantic Ridge (Azores)/northeast Atlantic (Portugal, Madeira) compared to populations around the Cape Verde Islands and in the northwest Atlantic. Some evidence of intraregional genetic differentiation between populations was found. Minimum‐spanning network analysis revealed star‐shaped patterns suggesting that populations had undergone expansion following bottlenecks and/or they have been colonized by jump dispersal events across large geographical distances along pathways of major ocean currents. Mismatch distribution analysis indicated that Azores and northwest Atlantic populations fitted a model of historical population expansion following a bottleneck/founder event estimated to be between 0.64 and 1.2 million years ago (Ma).
Genetic spatial structure of European common hamsters (Cricetus cricetus) — a result of repeated range expansion and demographic bottlenecks
Authors: NEUMANN K. , MICHAUX J. R. , MAAK S. , JANSMAN H. A. H. , KAYSER A. , MUNDT G. , GATTERMANN R. 
Published: April 2005

AbstractThe spatial genetic structure of common hamsters (Cricetus cricetus) was investigated using three partial mitochondrial (mt) genes and 11 nuclear microsatellite loci. All marker systems revealed significant population differentiation across Europe. Hamsters in central and western Europe belong largely to two allopatric mitochondrial lineages south and northwest of the Carpathian and Sudetes. The southern group, ‘Pannonia’, comprises populations inside the Carpathian basin (Czech Republic, Hungary) while the second group, ‘North’, includes hamsters from Belgium, the Netherlands, France, and Germany. Isolation of the lineages is maintained by a combination of geographical and ecological barriers. Both main phylogeographical groups show signs of further subdivision. North is separated into highly polymorphic central German and less polymorphic western populations, which most likely split during late glacial expansion (15 000–10 000 bp). Clock estimates based on haplotype distributions predict a divergence of the two major lineages 85 000–147 000bp. Expansion times fall during the last glaciation (115 000–10 000 bp) corroborating fossil data, which identifyCricetus cricetusas characteristic of colder climatic phases. Despite the allopatry of mt haplotypes, there is an overlap of nuclear microsatellite alleles between phylogeographical units. Although there are strong evidence that Pannonian hamsters have persisted inside the Carpathian basin over the last 50 000 years, genetic differentiation among European hamsters has mainly been caused by immigration from different eastern refugia. Possible source populations are likely to be found in the Ukrainian and the southern Russian plains — core areas of hamster distribution. From there, hamsters have repeatedly expanded during the Quaternary.
Sexual selection for male dominance reduces opportunities for female mate choice in the European bitterling (Rhodeus sericeus)
Authors: REICHARD M. , BRYJA J. , ONDRAČKOVÁ M. , DÁVIDOVÁ M. , KANIEWSKA P. , SMITH C. 
Published: April 2005

AbstractSexual selection involves two main mechanisms: intrasexual competition for mates and intersexual mate choice. We experimentally separated intrasexual (male–male interference competition) and intersexual (female choice) components of sexual selection in a freshwater fish, the European bitterling (Rhodeus sericeus). We compared the roles of multiple morphological and behavioural traits in male success in both components of sexual competition, and their relation to male reproductive success, measured as paternity of offspring. Body size was important for both female choice and male–male competition, though females also preferred males that courted more vigorously. However, dominant males often monopolized females regardless of female preference. Subordinate males were not excluded from reproduction and sired some offspring, possibly through sneaked ejaculations. Male dominance and a greater intensity of carotenoid‐based red colouration in their iris were the best predictors of male reproductive success. The extent of red iris colouration and parasite load did not have significant effects on female choice, male dominance or male reproductive success. No effect of parasite load on the expression of red eye colouration was detected, though this may have been due to low parasite prevalence in males overall. In conclusion, we showed that even though larger body size was favoured in both intersexual and intrasexual selection, male–male interference competition reduced opportunities for female choice. Females, despite being choosy, had limited control over the paternity of their offspring. Our study highlights the need for reliable measures of male reproductive success in studies of sexual selection.
Mucosal cytokine and antigen‐specific responses to Cryptosporidium parvum in IL‐12p40 KO mice
Authors: Ehigiator H. N. , Romagnoli P. , Borgelt K. , Fernandez M. , McNair N. , Secor W. E. , Mead J. R. 
Published: April 2005

SUMMARY Studies of cellular immune responses to Cryptosporidium parvum have been limited in part by lack of suitable animal models. IL‐12p40–/–mice are susceptible to initial infection with C. parvum but recover within 2 weeks, rendering the animals resistant to reinfection. Because the host responses that determine duration and severity of primary infection are not yet understood, we studied the cellular immune response to primary infection with C. parvum in IL‐12p40–/–mice and also explored possible mechanisms for this response. Female IL‐12p40–/–mice were inoculated with 10 000 oocysts. Uninfected age‐matched mice served as controls. At different time intervals following exposure to oocysts, mice were sacrificed and their intestine, spleen, and mesenteric lymph node tissues were harvested. Cellular immune responses to C. parvum were characterized. Infection of IL‐12p40–/–mice induced changes in the gene expression of the cytokines IFN‐γ, IL‐4, IL‐15, IL‐18, TNF‐α and TGF‐β during primary infection. There was also a significant increase in total numbers of lymphocytes and CD19/CD62L‐expressing cells in mesenteric lymph nodes. These MLN cells exhibited increased antigen‐specific proliferation and cytokine production (IL‐6 and IFN‐γ) levels when stimulated in vitro. These observations delineate the cellular immune responses during acute C. parvum infection of the IL‐12p40–/–mouse model.
Oral immunization with a live recombinant attenuated Salmonella typhimurium protects mice against Toxoplasma gondii
Authors: Cong H. , Gu Q. M. , Jiang Y. , He S. Y. , Zhou H. Y. , Yang T. T. , Li Y. , Zhao Q. L. 
Published: April 2005

SUMMARY The natural site of infection for T. gondii is the mucosal surface of the intestine, so the protective immunity obtained after natural infection with T. gondii points to the importance of developing a vaccine that stimulates mucosal defences. In this study, an aroA− and aroD− attenuated strain of Salmonella typhimurium (BRD509) has been used to deliver the recombinant eukaryotic plasmid pSAG1‐2/CTA2/B expressing a multi‐antigenic gene encoding SAG1 and SAG2 of T. gondii linked to A2/B subunits of cholera toxin as a candidate oral T. gondii vaccine. Immunoblot analysis showed compound gene expression in HeLa cells in vitro and intragastric immunization of mice with the recombinant salmonella resulted in the induction of humoral and Th1 type cellular immune responses and afforded protection against RH strain T. gondii challenge. Anti‐T. gondii IgG values increased markedly in the BRD509/pSAG1‐2‐CTA2/B immunized group; these values were significantly higher than those in the negative controls (P = 0·008). With CTA2/B genetic adjuvant, the T. gondii‐specific response was predominantly Th1, indicating that the CTA2/B genetic adjuvant was able to overcome the strong Th2‐bias of the antigen (IgG2a >> IgG1). Antigen‐specific T cell proliferative responses and CTL activity were significantly enhanced when cholera toxin CTA2/B genetic adjuvant was used (P = 0·009; P = 0·006). Culture supernatants from antigen‐stimulated splenocytes from mice in these groups were also examined by ELISA for Th1‐ and Th2‐type cytokines; mean IFN‐γ levels produced after oral immunization with BRD509/pSAG1‐2‐CTA2/B were about nine‐fold higher than after immunization with BRD509/pSAG1‐2 (P = 0·007). On the other hand, the levels of IL‐4 were low for all groups and no increase was seen in the presence of CTA2/B genetic adjuvant. When the immunized mice were intraperitoneally challenged with 103 tachyzoites of the highly virulent RH strain, the survival time of the mice immunized with BRD509/pSAG1‐2‐CTA2/B was markedly longer than other groups (P = 0·003) and a 40% survival rate was achieved. This is the first report that demonstrates that an oral attenuated salmonella DNA vaccine can induce protective immunity against the acute phase of T. gondii infection.
Cytokine mRNA expressions in symptomatic vs. asymptomatic amoebiasis patients
Authors: Bansal D. , Sehgal R. , Chawla Y. , Malla N. , Mahajan R. C. 
Published: April 2005

SUMMARYInfection with Entamoeba histolytica results in high mortality worldwide. Studies on the cytokine response in symptomatic and asymptomatic amoebiasis (caused by E. histolytica, the pathogenic species and E. dispar, the non‐pathogenic species) subjects and their correlation with symptomatology are lacking. The present study reports the cytokine response (TNF‐α, IFN‐γ, IL‐4, IL‐10 and TGF‐β) in such subjects as measured by RT‐PCR. The results showed significantly (< 0·05) higher expressions of IL‐10 and TGF‐β in the symptomatic group as compared to the asymptomatic and healthy controls. The cytokine profile indicated the role of suppressive immune response in symptomatic amoebiasis patients.