bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kin interactions and changing social structure during a population outbreak of feral house mice
Authors: SUTHERLAND DUNCAN R. , SPENCER PETER B. S. , SINGLETON GRANT R. , TAYLOR ANDREA C. 
Published: July 2005

AbstractPopulations of feral house mice (Mus domesticus L.) in Australia undergo multiannual fluctuations in density, and these outbreaks may be partly driven by some change in behavioural self‐regulation. In other vertebrate populations with multiannual fluctuations, changes in kin structure have been proposed as a causal mechanism for changes in spacing behaviour, which consequently result in density fluctuations. We tested the predictions of two alternative conceptual models based on kin selection in a population of house mice during such an outbreak. Both published models (Charnov & Finerty 1980; Lambin & Krebs 1991) propose that the level of relatedness between interacting individuals affects their behavioural response and that this changes with population density, though the nature of this relationship differs between the two models. Neither of the models was consistent with all observed changes in relatedness between interacting female mice; however, our results suggested that changes in kin structure still have potential for explaining why mouse outbreaks begin. Therefore, we have developed a variant of one of these conceptual models suggesting that the maintenance of female kin groups through the preceding winter significantly improves recruitment during the subsequent breeding season, and is therefore necessary for mouse outbreaks. We provide six testable predictions to falsify this hypothesis.
Phylogeography of sexualHeteronotia binoei(Gekkonidae) in the Australian arid zone: climatic cycling and repetitive hybridization
Authors: STRASBURG JARED L. , KEARNEY MICHAEL 
Published: July 2005

AbstractThe biota of much of continental Australia have evolved within the context of gradual aridification of the region over several million years, and more recently of climatic cycling between relatively dry and humid conditions. We performed a phylogeographical study of three sexual chromosome races of theHeteronotia binoeicomplex of geckos found throughout the Australian arid zone. Two of these three races were involved in two separate hybridization events leading to parthenogenetic lineages (alsoH. binoei), and the third is widespread and broadly sympatric with the parthenogens. Based on our analyses, the three sexual races diversified approximately 6 million years ago in eastern Australia, during a period of aridification, then each moved west through northern, southern, and central dispersal corridors to occupy their current ranges. In each case, the timing of major phylogeographical inferences corresponds to inferred palaeoclimatic changes in continental Australia. This scenario provides a simple explanation for diversification, secondary contact, and hybridization between the races. However, data presented elsewhere indicate that formation of the parthenogens was considerably more recent than the westward expansion of the hybridizing races, and that multiple hybridization events were geographically and temporally distinct. We suggest that cyclical climate changes may have led to regional range changes that facilitated hybridization between the races, which are not currently known to be in sympatry.
Phylogeny and historical biogeography of African ground squirrels: the role of climate change in the evolution of Xerus
Authors: HERRON M. D. , WATERMAN J. M. , PARKINSON C. L. 
Published: July 2005

AbstractWe used phylogenetic and phylogeographical methods to infer relationships among African ground squirrels of the genus Xerus. Using Bayesian, maximum‐parsimony, nested clade and coalescent analyses of cytochrome b sequences, we inferred interspecific relationships, evaluated the specific distinctness of Cape (Xerus inauris) and mountain (Xerus princeps) ground squirrels, and tested hypotheses for historical patterns of gene flow within X. inauris. The inferred phylogeny supports the hypothesized existence of an ‘arid corridor’ from the Horn of Africa to the Cape region. Although doubts have been raised regarding the specific distinctness of X. inauris and X. princeps, our analyses show that each represents a distinct well‐supported, monophyletic lineage. Xerus inauris includes three major clades, two of which are geographically restricted. The distributions of X. inauris populations are concordant with divergences within and disjunctions between other taxa, which have been interpreted as results of Plio–Pleistocene climate cycles. Nested clade analysis, coalescent analyses, and analyses of genetic structure support allopatric fragmentation as the cause of the deep divergences within this species.
Comparative host–parasite population structures: disentangling prospecting and dispersal in the black‐legged kittiwakeRissa tridactyla
Authors: McCOY KAREN D. , BOULINIER THIERRY , TIRARD CLAIRE 
Published: July 2005

AbstractAlthough much insight is to be gained through the comparison of the population genetic structures of parasites and hosts, there are, at present, few studies that take advantage of the information on vertebrate life histories available through the consideration of their parasites. Here, we examined the genetic structure of a colonial seabird, the black‐legged kittiwake (Rissa tridactyla) using seven polymorphic microsatellite markers to make inferences about population functioning and intercolony dispersal. We sampled kittiwakes from 22 colonies across the species’ range and, at the same time, collected individuals of one of its common ectoparasites, the tickIxodes uriae. Parasites were genotyped at eight microsatellite markers and the population genetic structure of host and parasite were compared. Kittiwake populations are only genetically structured at large spatial scales and show weak patterns of isolation by distance. This may be due to long‐distance dispersal events that erase local patterns of population subdivision. However, important additional information is gained by comparing results with those of the parasite. In particular, tick populations are strongly structured at regional scales and show a stepping‐stone pattern of gene flow. Due to the parasite's life history, its population structure is directly linked to the frequency and spatial extent of within‐breeding season movements of kittiwakes. The comparison of host and parasite gene flow therefore helps us to disentangle the intercolony movements of birds from that of true dispersal events (movement followed by reproduction). In addition, such data can provide essential elements for predicting the outcome of local co‐evolutionary interactions.
Phylogeographical disjunction in abundant high‐dispersal littoral gastropods
Authors: WATERS J. M. , KING T. M. , O'LOUGHLIN P. M. , SPENCER H. G. 
Published: July 2005

AbstractPhylogeographical disjunctions in high‐dispersal marine taxa are variously ascribed to palaeogeographical conditions or contemporary ecological factors. Associated biogeographical studies, however, seldom incorporate the sampling design required to confidently discriminate among such competing hypotheses. In the current study, over 7800 gastropod specimens were examined for operculum colour, and 129 specimens genetically, to test ecological and historical biogeographical hypotheses relating to biogeographical disjunction in the Southern Hemisphere, and to southern Australia in particular. Mitochondrial DNA sequence analysis of the high‐dispersal intertidal gastropod Nerita atramentosa in southern Australia (88 specimens; 18 localities) revealed an east–west phylogeographical split involving two highly divergent clades (26.0 ± 1.9%) exhibiting minimal geographical overlap in the southeast. The eastern clade of Nerita atramentosa is also widespread in northern New Zealand (43 specimens, 10 localities), but no significant genetic differentiation is explained by the Tasman Sea, a 2000‐km‐wide oceanic barrier. Spatial genetic structure was not detected within either clade, consistent with the species’ dispersive planktotrophic phase lasting for 5–6 months. Digital analysis of operculum colouration revealed substantial differences between eastern (tan) and western (black) specimens. Genetic analysis and visual inspection of 88 Australian specimens revealed a completely nonrandom association between mtDNA data and operculum colouration. Independent examination of a further 7822 specimens from 14 sites in southern Australia revealed both colour morphs at all localities, but reinforced the phylogeographical data by indicating a marked turnover in colour morph abundance associated with a palaeogeographical barrier: Wilsons Promontory. This sharp biogeographical disjunction is in marked contrast to the species’ high dispersal abilities. The genetic similarity of Nerita morio (Easter Island) and the eastern Australian + New Zealand lineage (1.1 ± 0.3%) provides further evidence of long‐distance dispersal in southern Nerita. Phylogenetic relationships of nine species (four genera) of Neritidae, an almost exclusively tropical gastropod family, are consistent with the hypothesis that southern temperate black nerites comprise a monophyletic radiation.
Variation for neutral markers is correlated with variation for quantitative traits in the plant pathogenic fungus Mycosphaerella graminicola
Authors: ZHAN J. , LINDE C. C. , JÜRGENS T. , MERZ U. , STEINEBRUNNER F. , McDONALD B. A. 
Published: July 2005

AbstractWe compared genetic variation and population differentiation at RFLP marker loci with seven quantitative characters including fungicide resistance, temperature sensitivity, pycnidial size, pycnidial density, colony size, percentage of leaves covered by pycnidia (PLACP) and percentage of leaves covered by lesions (PLACL) in Mycosphaerella graminicola populations sampled from four regions. Wide variation in population differentiation was found across the quantitative traits assayed. Fungicide resistance, temperature sensitivity, and PLACP displayed a significantly higher QST than GST, consistent with selection for local adaptation, while pycnidial size, pycnidial density and colony size displayed a lower or significantly lower QST than GST, consistent with constraining selection. There was not a statistical difference between QST and GST in PLACL. We also found a positive and significant correlation between genetic variation in molecular marker loci and quantitative traits at the multitrait scale, suggesting that estimates of overall genetic variation for quantitative traits in M. graminicola could be derived from analysis of the molecular genetic markers.
Ancient DNA from pollen: a genetic record of population history in Scots pine
Authors: PARDUCCI L. , SUYAMA Y. , LASCOUX M. , BENNETT K. D. 
Published: July 2005

AbstractAssessments of plant population dynamics in space and time have depended on dated records of fossil pollen synthesized on a subcontinental scale. Genetic analyses of extant populations have revealed spatial relationships that are indicative of past spatial dynamics, but lack an explicit timescale. Synthesis of these data requires genetic analyses from abundant dated fossil material, and this has hitherto been lacking. Fossil pollen is the most abundant material with which to fill this data gap. Here we report genetic analyses of fossil pollen retrieved from Holtjärnen postglacial lake sediment in Sweden and show that plastid DNA is recoverable from Scots Pine and Norway spruce pollen grains that are 100 and 10 000 years old. By sequencing clones from two short plastid PCR products and by using multiple controls we show that the ancient sequences were endogenous to the fossil grains. Comparison of ancient sequences and those obtained from an extant population of Scots pine establishes the first genetic link between extant and fossil samples in this species, providing genetic continuity through time. The finding of one common haplotype present in modern, 100‐year old and 10 000‐year old samples suggests that it may have persisted near Holtjärnen throughout the postglacial period. This retrieval of ancient DNA from pollen has major implications for plant palaeoecology in conifer species by allowing direct estimates of population dynamics in space and time.
Dumping in a Linder Model of Trade with Multiple Retail Channels
Authors: Chung Ling Wei , Hartigan James C. 
Published: July 2005

AbstractThe last decade has witnessed an accelerating adoption of AD laws by LDCs and their increasing usage against developed countries. Our model of third degree price discrimination with heterogenous consumers that have differing preferences for quality in the two countries suggests that this is likely to continue. Duopolistic interaction may yield bilateral dumping, or unilateral dumping in either direction, under free trade. Even when dumping is unidirectional, there is a compelling basis for the introduction of AD laws by both governments. This mitigates competition, which is beneficial for both firms, and portends pessimism for an abatement of this recent proliferation of AD laws and complaints.
On the Equivalence of Tariffs and Quotas under a Revenue Constraint
Authors: Chiou Jiunn‐Rong , Hwang Hong , Lin Yan‐Shu 
Published: July 2005

AbstractThis paper sets out a duopolistic model to examine the price and welfare equivalence of tariffs and quotas, given the quota rent is equal to the tariff revenue. It shows that the domestic welfare ranking of the two trade policies crucially depends on the relative costs of the domestic and foreign firms; when the domestic firm's relative costs are lower than those of the foreign firm, a quota regime generally leads to a higher welfare level than that of an equivalent tariff regime. This finding contrasts sharply with the conclusions of Dasgupta and Stiglitz (1977), where it was found that a tariff regime always generates higher domestic welfare.
Income Inequality and Macroeconomic Volatility: An Empirical Investigation
Authors: Breen Richard , García‐Peñalosa Cecilia 
Published: July 2005

AbstractWe explore the impact of macroeconomic volatility on the distribution of income. Using a cross‐section of developed and developing countries, we find that greater output volatility, defined as the standard deviation of the rate of output growth, is associated with a higher Gini coefficient and income share of the top quintile. The coefficients suggest that a strong effect on inequality resulting from a reduction in volatility: the Gini coefficient of a country like Chile would fall by 6 points if it were to reduce its volatility to the same level as Sweden or Norway. Our results seem not to be driven by the high‐inequality/high‐volatility Latin American countries.
Caste, Inequality, and Poverty in India
Authors: Borooah Vani K. 
Published: July 2005

AbstractThis paper analyses inequality and poverty in India within the context of caste‐based discrimination. It does so by decomposing the difference between (caste) Hindu and Scheduled Caste (SC) and Scheduled Tribe (ST) households in: their average household incomes; their probabilities of being in different income percentiles; their probabilities of being at different levels of poverty into: a “discrimination effect”, which stems from the fact that a household's income level, into which its (income‐generating) profile translates, depends on whether it is SC/ST; an “attributes (or residual) effect” which stems from the fact that there are systematic differences between SC/ST and Hindu households in their (income‐generating) profiles. The results, based on unit record data for 28,922 households, showed that at least one‐third of the average income/probability differences between Hindu and SC/ST households was due to the “unequal treatment” of the latter.
The Persistence of Income Shocks: Evidence from Rural Indonesia
Authors: Newhouse David 
Published: July 2005

AbstractThis paper estimates the persistence of transient income shocks to farm households in rural Indonesia. Persistence is defined as the elasticity of a household's 1997 household per capita income with respect to its 1993 per capita income, controlling for time‐invariant characteristics of the household. Local rainfall levels are used as an exogenous source of transitory variation in 1993 income. Four main conclusions emerge. First, roughly 30% of household income shocks remain after four years. Second, the persistence of negative and positive shocks is approximately equal; if anything, positive shocks last longer. Third, neither positive nor negative income shocks disproportionately affect poor households. Finally, measurement error in income and unobserved household heterogeneity are important sources of bias. These findings cast doubt on common arguments advocating public intervention to stabilize or redistribute income, and suggest that anti‐poverty policy should address more permanent causes of household poverty.
Gene expression profiling of cultured human NF1 heterozygous (NF1+/–) melanocytes reveals downregulation of a transcriptional cis‐regulatory network mediating activation of the melanocyte‐specific dopachrome tautomerase (DCT) gene
Authors: Boucneau Joachim , De Schepper Sofie , Vuylsteke Marnik , Van Hummelen Paul , Naeyaert Jean‐Marie , Lambert Jo 
Published: July 2005

SummaryOne of the major primary features of the neurocutaneous genetic disorder Neurofibromatosis type 1 are the hyperpigmentary café‐au‐lait macules where disregulation of melanocyte biology is supposed to play a key etiopathogenic role. To gain better insight into the possible role of the tumor suppressor gene NF1, a transcriptomic microarray analysis was performed on human NF1 heterozygous (NF1+/–) melanocytes of a Neurofibromatosis type 1 patient and NF1 wild type (NF1+/+) melanocytes of a healthy control patient, both cultured from normally pigmented skin and hyperpigmented lesional café‐au‐lait skin. From the magnitude of gene effects, we found that gene expression was affected most strongly by genotype and less so by lesional type. A total of 137 genes had a significant twofold or more up‐ (72) or downregulated (65) expression in NF1+/– melanocytes compared with NF1+/+ melanocytes. Melanocytes cultured from hyperpigmented café‐au‐lait skin showed 37 upregulated genes whereas only 14 were downregulated compared with normal skin melanocytes. In addition, significant genotype ×lesional type interactions were observed for 465 genes. Differentially expressed genes were mainly involved in regulating cell proliferation and cell adhesion. A high number of transcription factor genes, among which a specific subset important in melanocyte lineage development, were downregulated in the cis‐regulatory network governing the activation of the melanocyte‐specific dopachrome tautomerase (DCT) gene. Although the results presented have been obtained with a restricted number of patients (one NF1 patient and one control) and using cDNA microarrays that may limit their interpretation, the data nevertheless addresses for the first time the effect of a heterozygous NF1 gene on the expression of the human melanocyte transcriptome and has generated several interesting candidate genes helpful in elucidating the etiopathology of café‐au‐lait macules in NF1 patients.
The ocular albinism type 1 (OA1) protein and the evidence for an intracellular signal transduction system involved in melanosome biogenesis
Authors: Schiaffino M. Vittoria , Tacchetti Carlo 
Published: July 2005

SummaryOcular albinism type 1 is an X‐linked disorder characterized by severe reduction of visual acuity, retinal hypopigmentation, foveal hypoplasia, optic misrouting and the presence of giant melanosomes (macromelanosomes) in skin melanocytes and retinal pigment epithelium. The protein product of the OA1 gene is a pigment cell specific membrane glycoprotein, displaying structural and functional features of G protein‐coupled receptors (GPCRs). However, in contrast to all other previously characterized GPCRs, OA1 is not localized to the plasma membrane, but is targeted to intracellular organelles, namely late endosomes/lysosomes and melanosomes. These unique characteristics suggest that OA1 represents the first example described so far of an exclusively intracellular GPCR and regulates melanosome biogenesis by transducing signals from the organelle lumen to the cytosol. These findings support previous hypotheses that GPCR‐mediated signaling might also operate at the internal membranes in mammalian cells.
Early disease onset and increased risk of other autoimmune diseases in familial generalized vitiligo
Authors: Laberge Greggory , Mailloux Christina M. , Gowan Katherine , Holland Paulene , Bennett Dorothy C. , Fain Pamela R. , Spritz Richard A. 
Published: July 2005

SummaryGeneralized vitiligo is an autoimmune disorder in which acquired white patches of skin and overlying hair result from autoimmune loss of melanocytes from involved areas. Although usually sporadic, family clustering of vitiligo may occur, in a non‐Mendelian pattern typical of multifactorial, polygenic inheritance. Sporadic vitiligo is associated with autoimmune thyroid disease, pernicious anemia, Addison's disease, and lupus; these same disorders occur at increased frequency in patients’ first‐degree relatives. Here, we studied 133 ‘multiplex’ generalized vitiligo families, with multiple affected family members. The age of onset of vitiligo is earlier in these ‘multiplex’ families than in patients with sporadic vitiligo. Affected members of the multiplex vitiligo families have elevated frequencies of autoimmune thyroid disease, rheumatoid arthritis, psoriasis, adult‐onset insulin‐dependent diabetes mellitus, pernicious anemia, and Addison's disease. Probands’ unaffected siblings have elevated frequencies of most of these same autoimmune diseases, particularly if the proband had non‐vitiligo autoimmune disease. Familial generalized vitiligo is thus characterized by earlier disease onset and a broader repertoire of associated autoimmune diseases than sporadic vitiligo. This mostly likely reflects a greater inherited genetic component of autoimmune susceptibility in these families. These findings have important implications for autoimmune disease surveillance in families in which multiple members are affected with vitiligo.
Melanocytes in conditional Rb–/– mice are normal in vivo but exhibit proliferation and pigmentation defects in vitro
Authors: Tonks Ian D. , Hacker Elke , Irwin Nicole , Muller H. Konrad , Keith Patricia , Mould Arne , Zournazi Anna , Pavey Sandra , Hayward Nicholas K. , Walker Graeme , Kay Graham F. 
Published: July 2005

SummaryThe function of the retinoblastoma tumour suppressor (Rb1), and the pocket protein family in general, has been implicated as an important focal point for deregulation in many of the molecular pathways mutated in melanoma. We have focused on the role of Rb1 in mouse melanocyte homeostasis using gene targeting and Cre/loxP mediated tissue‐specific deletion. We show that constitutive Cre‐mediated ablation of Rb1 exon 2 prevents the production of Rb1 and recapitulates the phenotype encountered in other Rb1 knockout mouse models. Mice with conditional melanocyte‐specific ablation of Rb1 manifest overtly normal pigmentation and are bereft of melanocytic hyperproliferative defects or apoptosis‐induced depigmentation. Histologically, these mice have melanocyte morphology and distribution comparable with control littermates. In contrast, Rb1‐null melanocytes removed from their in vivo micro‐environment and cultured in vitro display some of the characteristics associated with a transformed phenotype. They proliferate at a heightened rate when compared with control melanocytes and have a decreased requirement for mitogens. With progressive culture the cells depigment at relatively early passage and display a gross morphology which, whilst reminiscent of early passage melanocytes, is generally different to equivalent passage control cells. These results indicate that Rb1 is dispensable for in vivo melanocyte homeostasis when its ablation is targeted from the melanoblast stage onwards, however, when cultured in vitro, Rb1 loss increases melanocyte growth but the cells are not fully transformed.