bluuebunny/crossref_metadata_2025_split huggingface dataset:
Melatonin: From Seasonal to Circadian Signal
Authors: Pévet P. 
Published: May 2003

AbstractIn mammals, the role of melatonin in the control of seasonality is well documented, and the sites and mechanisms of action involved are beginning to be identified. The exact role of the hormone in the circadian timing system remains to be determined. However, exogenous melatonin has been shown to affect the circadian clock. Identification of the molecular and cellular mechanisms involved in this well characterized chronobiotic effect will allow clarification of the role of endogenous melatonin in circadian organization
English names for a world list of mammals, exemplified by species of Indochina
Authors: DUCKWORTH J. W. , PINE RONALD H. 
Published: May 2003

ABSTRACT 1. The lack of a globally accepted list of English‐language names for mammal species leads to various problems stemming from the reduced ability to communicate unambiguously. This impacts directly on their conservation. We use the larger mammals of Indochina to exemplify the use of an explicit set of principles designed to provide each species with a unique and non‐misleading (or at least minimally so) English name. 2. For most species, a suitable name is already in use, sometimes generally so. For species for which multiple names are in use, standardization would consist of adopting the most suitable name. Only for a very few species are all extant names so unsuitable that a neologism should be coined. One species, Panthera pardus, presents potentially insoluble problems. 3. Name standardization among the world's birds has generated some controversy, but this has not led to abandonment of the process. Much can be learned by those developing a similar process for mammals, through studying the bird‐naming process. Progress can be advanced by detractors indicating whether they oppose standardization per se, the principles used or the names resulting from application of the principles. Also, proponents of standardization should always emphasize that the purpose of the process is to produce a list available for those who want to use it, not to produce a binding selection that must be used in all circumstances.
Predation of wildlife by domestic catsFelis catusin Great Britain
Authors: WOODS MICHAEL , MCDONALD ROBBIE A. , HARRIS STEPHEN 
Published: May 2003

ABSTRACT1. A questionnaire survey of the numbers of animals brought home by domestic catsFelis catuswas conducted between 1 April and 31 August 1997. A total of 14 370 prey items were brought home by 986 cats living in 618 households. Mammals made up 69% of the items, birds 24%, amphibians 4%, reptiles 1%, fish < 1%, invertebrates 1% and unidentified items 1%. A minimum of 44 species of wild bird, 20 species of wild mammal, four species of reptile and three species of amphibian were recorded.2. Of a sample of 696 individual cats, 634 (91%) brought home at least one item and the back‐transformed mean number of items brought home was 11.3 (95% CI 10.4–12.2). The back‐transformed means and number of cats retrieving at least one item from each prey group were: 8.1 (7.4–8.9) mammals for 547 (79%) cats, 4.1 (3.8–4.5) birds for 506 (73%) cats, 2.6 (2.2–3.0) herpetofauna for 145 (21%) cats and 2.2 (1.8–2.7) other items for 98 (14%) cats.3. The number of birds and herpetofauna brought home per cat was significantly lower in households that provided food for birds. The number of bird species brought home was greater in households providing bird food. The number of birds and herpetofauna brought home per cat was negatively related to the age and condition of the cat. The number of mammals brought home per cat was significantly lower when cats were equipped with bells and when they were kept indoors at night. The number of herpetofauna brought home was significantly greater when cats were kept in at night.4. Based on the proportion of cats bringing home at least one prey item and the back‐transformed means, a British population of approximately 9 million cats was estimated to have brought home in the order of 92 (85–100) million prey items in the period of this survey, including 57 (52–63) million mammals, 27 (25–29) million birds and 5 (4–6) million reptiles and amphibians.5. An experimental approach should be taken to investigate the factors found by this descriptive survey to influence the numbers of prey brought home by cats. In particular, investigation of potential management practices that could reduce the numbers of wild animals killed and brought home by cats will be useful for wildlife conservation, particularly in suburban areas.
Phylogeography of the Northern short‐tailed shrew, Blarina brevicauda (Insectivora: Soricidae): past fragmentation and postglacial recolonization
Authors: Brant Sara V. , Ortí Guillermo 
Published: May 2003

Abstract Blarina brevicauda is distributed across the northeastern region of North America, in areas previously covered by Pleistocene glaciers. Previous molecular systematic study of the species in the genus Blarina suggested the presence of two distinct eastern and western phylogroups within B. brevicauda, in agreement with traditionally recognized semi‐species. To expand the previous work, a collection of 76 individuals from 14 localities collected throughout the range of B. brevicauda was used to assess the mitochondrial (mt) cytochrome b genealogy for this species. Minimum evolution, maximum parsimony, analysis of molecular variance and nested clade analysis each supported the same conclusions of two well‐differentiated and monophyletic east–west groups, separated by the Mississippi River. Denser sampling in areas immediately East of the Mississippi basin revealed further subdivision within the eastern phylogroup into an East‐Central and an Appalachian clade. The western phylogroup differed from the eastern phylogroup by 2.5% mean absolute DNA sequence difference. About 65% of the genetic variance among samples was explained by the east–west subdivision alone. High haplotype diversities, low nucleotide diversities and unimodal mismatch distributions within subclades suggest recent expansion or diversification within each group. No phylogeographic structure was found within the western phylogroup, but genetic structure because of restricted gene flow and isolation by distance was inferred for the eastern group. The present distribution of B. brevicauda is best explained by past fragmentation and range expansion events during and following the Pleistocene glacial cycles.
Chloroplast DNA phylogeography reveals colonization history of a Neotropical tree, Cedrela odorata L., in Mesoamerica
Authors: Cavers S. , Navarro C. , Lowe A. J. 
Published: May 2003

AbstractSpanish Cedar (Cedrela odorata L.) is a globally important timber species which has been severely exploited in Mesoamerica for over 200 years. Using polymerase chain reaction–restriction fragment length polymorphisms, its chloroplast (cp) DNA phylogeography was studied in Mesoamerica with samples from 29 populations in six countries. Five haplotypes were characterized, phylogenetically grouped into three lineages (Northern, Central and Southern). Spatial analysis of ordered genetic distance confirmed deviation from a pattern of isolation by distance. The geographically proximate Northern and Central cpDNA lineages were genetically the most differentiated, with the Southern lineage appearing between them on a minimum spanning tree. However, populations possessing Southern lineage haplotypes occupy distinct moist habitats, in contrast to populations possessing Northern and Central lineage haplotypes which occupy drier and more seasonal habitats. Given the known colonization of the proto‐Mesoamerican peninsula by South American flora and fauna prior to the formation of the Isthmus of Panama, it seems most likely that the observed population structure in C. odorata results from repeated colonization of Mesoamerica from South American source populations. Such a model would imply an ancient, pre‐Isthmian colonization of a dry‐adapted type (possessing the Northern lineage or a prototype thereof), with a secondary colonization via the land bridge. Following this, a more recent (possibly post‐Pleistocene) expansion of moist‐adapted types possessing the Southern lineage from the south fits the known vegetation history of the region.
Population substructures in the soil invertebrateOrchesella cincta, as revealed by microsatellite and TE‐AFLP markers
Authors: Van Der Wurff A. W. G. , Isaaks J. A. , Ernsting G. , Van Straalen N. M. 
Published: May 2003

AbstractMicrosatellite and three enzyme–amplified fragment length polymorphism (TE‐AFLP) DNA markers were used to describe the population genetic structure in the soil dwelling collembolanOrchesella cincta(L.). Two forests were sampled according to a three‐level nested hierarchical design, with fixed distances among samples within a parcel and among parcels within a forest. The largest component of variation was found at the smallest scale, within parcels (77–97%), while the smallest component of variation was found between forests. The two different methods to study population structure indicated a similar allocation of variance. Population genetic substructuring was revealed between samples on a scale of 50 m; the degree of substructuring however, varied between parcels and forests. One forest showed a high degree of structure as revealed by microsatellites, while another showed a low degree of structure. A significant deviation from random‐mating (averageFIS = 0.23) over the two forests was detected. Two of 18 samples showed a difference in population genetic structure between males and females. We discuss the fact that the population genetic structure ofO. cinctais significantly affected by long‐range dispersal, even though it is a small and wingless insect. This interpretation is supported by observations on tree‐climbing behaviour in this species that may facilitate air dispersal. As a consequence, the assumption that migrationa priorimay be neglected in demographic analysis ofO. cinctais incorrect.
Phylogeography of Cavernularia hultenii: evidence of slow genetic drift in a widely disjunct lichen
Authors: Printzen C. , Ekman S. , Tønsberg T. 
Published: May 2003

AbstractPopulation structure and history is poorly known in most lichenized ascomycetes. Many species display large‐scale infraspecific disjunctions, which have been explained alternately by range fragmentation in species of high age and widespread long‐distance dispersal. Using the lichen Cavernularia hultenii, which is widely disjunct across North America and Europe, Pleistocene and Holocene population history was inferred. The internal transcribed spacer (ITS) and part of the the intergenic spacer (IGS) region of the nuclear ribosomal DNA were sequenced in 300 individuals representing 62 populations across the range of the species. While four ancestral haplotypes are found in all areas, none of the observed tip haplotypes is present in more than one of the three part ranges. Although this is evidence for a past fragmentation event, nested clade analysis (NCA) remains equivocal in the choice between allopatric fragmentation and long‐distance dispersal. Mismatch distributions indicate exponential population growth, probably during postglacial invasion of C. hultenii into formerly glaciated areas of western North America. The presence of one southern and at least one northern glacial refugium in South Central Alaska is inferred. Evidence for another refugium in the Queen Charlotte Islands or Alexander Archipelago is inconclusive because of sparse sampling. However, a range expansion was not confirmed unambiguously by NCA. The limited power of NCA to infer past range fragmentations and expansions is due apparently to the shallow haplotype network and widespread ancestral haplotypes. This can be explained by slow genetic drift causing incomplete removal of ancestral haplotypes from the postfragmentation and postexpansion areas.
Differential patterns of hybridization and introgression between the swallowtailsPapilio machaonandP. hospitonfrom Sardinia and Corsica islands (Lepidoptera, Papilionidae)
Authors: Cianchi R. , Ungaro A. , Marini M. , Bullini L. 
Published: May 2003

AbstractProportions of hybridization and introgression between the swallowtailsPapilio hospiton, endemic to Sardinia and Corsica, and the holarcticPapilio machaon, were characterized using nine fully diagnostic and two differentiated allozyme loci and a mitochondrial DNA marker. Very low frequencies of F1hybrids were detected in both Sardinia (0–4%, average 1.4%) and Corsica (0–3%, average 0.5%), as well as of first generation backcrosses (B1). No F2were observed, in agreement with the hybrid breakdown detected in laboratory crosses. In spite of this minimal current gene exchange, specimens carrying introgressed alleles were found in high proportions inP. machaonbut in lower proportions inP. hospiton. Introgression apparently occurred through past hybridization and repeated backcrossing, as evidenced by hybrid index scores and Bayesian assignment tests. Levels of introgression were low (0–1%) at two sex‐linked loci and mitochondrial DNA, limited (0.4–2%) at three autosomal loci coding for dimeric enzymes, and high (up to 43%) at four autosomal loci coding for monomeric enzymes. Accordingly, selective filters are acting against foreign alleles, with differential effectiveness depending on the loci involved. The low levels of introgression at sex‐linked loci and mitochondrial DNA are in agreement with Haldane's rule and suggest that introgression inP. machaonproceeds mainly through males, owing to a lower fitness of hybrid females.Papilio machaonpopulations showed higher levels of introgression in Sardinia than in Corsica. The role of reinforcement in the present reproductive isolation betweenP. machaonandP. hospitonis examined, as well as the evolutionary effects of introgressive hybridization between the two species.
Patch establishment and development of a clonal plant, Polygonum cuspidatum, on Mount Fuji
Authors: Zhou Zhihua , Miwa Makoto , Nara Kazuhide , Wu Bingyun , Nakaya Hironobu , Lian Chunlan , Miyashita Naoya , Oishi Ryuuya , Maruta Emiko , Hogetsu Taizo 
Published: May 2003

AbstractMicrosatellite analysis was used to investigate the patch establishment and development of Polygonum cuspidatum Sieb. et Zucc, a clonal herbaceous plant that dominates the primary succession on the southeast slope of Mount Fuji. Genotypes of P. cuspidatum in 155 patches at the study site differed from each other. This indicates that P. cuspidatum patches are initially established by seed dispersed on the bare scoria field, and not by clonal rhizome extension. Genetic differentiation was estimated using the FST values between subpopulations at the study site. There was almost no genetic differentiation between subpopulations, indicating the presence of massive gene flow. The pollen fathers of seeds and maternal genets of current‐year seedlings were inferred from the microsatellite allele composition by a simple exclusion method. The wide, random distribution of pollen fathers suggests that pollen dispersal occurs over a broad area. Maternal analysis showed a tendency for seed dispersal to be biased to the area nearby and down slope from the mother plants. Patch establishment under massive gene flow may result from such pollen and seed dispersal. To understand the process of patch development, aerial photographs taken from 1962 to 1999 were compared, and then genets in each of 36 patches were identified from the microsatellite genotypes of P. cuspidatum shoots. The comparison of aerial photographs showed that most of the patches enlarged each year and that some neighbouring patches combined during growth. Genet analysis demonstrated a high correlation between patch area and the area of the largest genet within it, and that new genets were recruited at the patch periphery. These findings indicate that both vegetative and sexual reproduction, i.e. rhizome extension and the establishment of new seedlings, contribute to the development of P. cuspidatum patches.
Phylogeography of maritime pine inferred with organelle markers having contrasted inheritance
Authors: Burban C. , Petit R. J. 
Published: May 2003

AbstractRange‐wide variation of maritime pine was studied at maternally inherited and paternally inherited markers (mitochondrial DNA and chloroplast DNA). While chloroplast DNA exhibits the highest diversity, phylogeographic inferences from this marker are blurred by homoplasy and extensive pollen flow. In contrast, the only three mitochondrial haplotypes found provide a clear picture of nonoverlapping areas colonized from different refugia, with no single population having a mixed composition (GST = 1). Comparison of the genetic structure inferred from both organelle genomes allows the investigation of differential seed and pollen dispersal, pointing to pollen, but not seed, dispersal across the Strait of Gibraltar (from Morocco into Iberia). A comparison with already available genetic information, especially that of one of the maritime pine's most threatening insect pests, the bast scale Matsucoccus feytaudi, further completes the picture.
Evidence of a hybrid‐zone in Atlantic cod (Gadus morhua) in the Baltic and the Danish Belt Sea revealed by individual admixture analysis
Authors: Nielsen Einar E. , Hansen Michael M. , Ruzzante Daniel E. , Meldrup Dorte , Grønkjær Peter 
Published: May 2003

AbstractThe study of hybrid zones is central to our understanding of the genetic basis of reproductive isolation and speciation, yet very little is known about the extent and significance of hybrid zones in marine fishes. We examined the population structure of cod in the transition area between the North Sea and the Baltic Sea employing nine microsatellite loci. Genetic differentiation between the North Sea sample and the rest increased along a transect to the Baltic proper, with a large increase in level of differentiation occurring in the Western Baltic area. Our objective was to determine whether this pattern was caused purely by varying degrees of mechanical mixing of North Sea and Baltic Sea cod or by interbreeding and formation of a hybrid swarm. Simulation studies revealed that traditional Hardy–Weinberg analysis did not have sufficient power for detection of a Wahlund effect. However, using a model‐based clustering method for individual admixture analysis, we were able to demonstrate the existence of intermediate genotypes in all samples from the transition area. Accordingly, our data were explained best by a model of a hybrid swarm flanked by pure nonadmixed populations in the North Sea and the Baltic Sea proper. Significant correlation of gene identities across loci (gametic phase disequilibrium) was found only in a sample from the Western Baltic, suggesting this area as the centre of the apparent hybrid zone. A hybrid zone for cod in the ecotone between the high‐saline North Sea and the low‐saline Baltic Sea is discussed in relation to its possible origin and maintenance, and in relation to a classical study of haemoglobin variation in cod from the Baltic Sea/Danish Belt Sea, suggesting mixing of two divergent populations without interbreeding.
An empirical exploration of data quality in DNA‐based population inventories
Authors: Paetkau D. 
Published: May 2003

AbstractI present data from 21 population inventory studies — 20 of them on bears — that relied on the noninvasive collection of hair, and review the methods that were used to prevent genetic errors in these studies. These methods were designed to simultaneously minimize errors (which can bias estimates of abundance) and per‐sample analysis effort (which can reduce the precision of estimates by limiting sample size). A variety of approaches were used to probe the reliability of the empirical data, producing a mean, per‐study estimate of no more than one undetected error in either direction (too few or too many individuals identified in the laboratory). For the type of samples considered here (plucked hair samples), the gain or loss of individuals in the laboratory can be reduced to a level that is inconsequential relative to the more universal sources of bias and imprecision that can affect mark–recapture studies, assuming that marker systems are selected according to stated guidelines, marginal samples are excluded at an early stage, similar pairs of genotypes are scrutinized, and laboratory work is performed with skill and care.
Molecular evidence reveals a polyphyletic origin and chromosomal speciation of Lake Baikal's endemic asellid isopods
Authors: Hidding B. , Michel E. , Natyaganova A. V. , Sherbakov D. YU. 
Published: May 2003

AbstractThe six endemic isopod species of Lake Baikal have been regarded as a small species flock with uncertain affinities to related asellids. We provide evidence from 16S rRNA sequences for polyphyletic origins of Baikalian Asellidae. One clade of two species is related to the Eurasian genus Asellus. The other clade, Baicalasellus, shows affinities to North American asellids and may have a long evolutionary history within the lake basin. Some speciation events within Baicalasellus clearly have a chromosomal basis. In contrast with numerous taxa exhibiting monophyletic radiations in ancient lakes, the endemic Baikalian isopods arose by multiple invasions and chromosomal mechanisms.
Estimating population sizes for elusive animals: the forest elephants of Kakum National Park, Ghana
Authors: Eggert L. S. , Eggert J. A. , Woodruff D. S. 
Published: May 2003

AbstractAfrican forest elephants are difficult to observe in the dense vegetation, and previous studies have relied upon indirect methods to estimate population sizes. Using multilocus genotyping of noninvasively collected samples, we performed a genetic survey of the forest elephant population at Kakum National Park, Ghana. We estimated population size, sex ratio and genetic variability from our data, then combined this information with field observations to divide the population into age groups. Our population size estimate was very close to that obtained using dung counts, the most commonly used indirect method of estimating the population sizes of forest elephant populations. As their habitat is fragmented by expanding human populations, management will be increasingly important to the persistence of forest elephant populations. The data that can be obtained from noninvasively collected samples will help managers plan for the conservation of this keystone species.
Genetic marker investigation of the source and impact of predation on a highly endangered species
Authors: Banks Sam C. , Horsup Alan , Wilton Alan N. , Taylor Andrea C. 
Published: May 2003

AbstractIn September and October 2000, the remains of a number of apparently predated northern hairy‐nosed wombats (Lasiorhinus krefftii) were discovered in Epping Forest National Park, the site of the only known population of this highly endangered species. Analysis of DNA recovered from six carcasses and a section of intestine found nearby was carried out using microsatellite and Y‐specific primers. This identified seven individual wombats, the identity of three of which was inferred from a genotype database prepared from animals sampled during trapping programmes. Six victims were male and one female, suggesting that female‐biased predation rates are unlikely to be the cause of the current male‐biased population sex ratio. DNA isolated from four canid faeces found in the vicinity revealed three distinct canid microsatellite genotypes with very high probabilities of belonging to dingoes (Canis familiaris dingo). A wombat genotype matching that of one of the dead individuals was identified from scats of two of the dingoes. In addition, two macropod microsatellites were amplified from two dingo scats. These observations provided vital information regarding predation on northern hairy‐nosed wombats, and prompted the permanent exclusion of dingoes from the park by the erection of a dingo‐proof fence.