bluuebunny/crossref_metadata_2025 huggingface dataset:
An Essential Role for Peptidergic Signalling in the Control of Circadian Rhythms in the Suprachiasmatic Nuclei
Authors: Harmar A. J.
Published: May 2003

Two structurally related neuropeptides, pituitary adenylate cyclase‐activating polypeptide (PACAP), colocalized with glutamate in neurones of the retinohypothalamic tract, and vasoactive intestinal peptide (VIP), present in light‐responsive cells of the suprachiasmatic nuclei (SCN), appear to play distinct and important roles in the control of mammalian circadian rhythms. Mice deficient in the PACAP‐selective PAC1 receptor exhibit altered responsiveness of the SCN clock to light‐induced phase‐shifts, but display robust circadian patterns of wheel‐running behaviour. By contrast, our studies of mice lacking the VPAC2 receptor, which responds to both PACAP and VIP, indicate that this receptor plays a critical role in rhythm generation in the SCN. The predominant factor determining wheel‐running activity in VPAC2 receptor null (Vipr2–/–) mice is ‘masking’ by light. Mutant animals re‐entrain immediately to advances or delays in the light/dark cycle and do not exhibit robust circadian rhythms of behaviour when in constant darkness. The mice do not exhibit circadian expression of core clock genes (mPer1, mPer2, mCry1), or of the clock‐controlled gene arginine vasopressin (AVP), in the SCN. We propose that VIP signalling between SCN neurones provides a paracrine reinforcing signal that is essential for sustained rhythm generation. The presence of VIP signalling in the SCN may explain why SCN neurones are capable of generating long‐lasting self‐sustained oscillations, whereas rhythmic clock gene expression in other tissues is dependent on periodic reinforcement by neural or hormonal signals.
Optimization of Light and Melatonin to Phase‐Shift Human Circadian Rhythms
Authors: Skene D. J.
Published: May 2003

Both light and melatonin, appropriately timed, have been shown to phase‐shift human circadian rhythms. In addition, both light and melatonin have acute physiological and behavioural effects. Depending on the dose, melatonin can reduce core body temperature and induce sleepiness. Conversely, light at night increases body temperature and enhances alertness and performance. The acute and phase‐shifting effects of light and melatonin have justified their investigation and use in the treatment of circadian rhythm sleep disorders. Melatonin is the treatment of choice for blind people with non‐24 h sleep/wake disorder. Current research is directed towards optimizing these therapies with respect to time of administration, dose and formulation of melatonin, intensity, duration and spectral composition of light. Our studies in totally blind people with non‐24 h sleep/wake disorder have shown that, in addition to improving sleep, daily administration of melatonin can entrain their free‐running circadian rhythms. The ability of melatonin to entrain free‐running rhythms depends, in part, on the time of melatonin administration relative to the subject's circadian phase. Subjects who were entrained by melatonin began their treatment in the phase advance portion (CT 6–18) of the published melatonin phase‐response curves (PRCs), whereas those who failed to entrain began their melatonin treatment in the delay portion of the PRC. Whether the effect of light on the human circadian axis can be optimized by altering its spectral composition has been investigated. Recently, it was demonstrated that light‐induced melatonin suppression in humans is sensitive to short wavelength light (420–480 nm; λmax approximately 460 nm), a response very different to the classical scotopic and photopic visual systems. Whether other nonvisual light responses (e.g. circadian phase resetting) show a similar spectral sensitivity is currently being studied.
Leptin and Seasonal Mammals
Authors: Rousseau K. , Atcha Z. , Loudon A. S. I.
Published: May 2003

Seasonal mammals commonly exhibit robust annual cycles of adiposity, food intake and energy metabolism. These cycles are driven by changes in the external daylength signal, which generates a diurnal melatonin profile and acts on neuroendocrine pathways. The white adipose tissue hormone leptin reflects overall adiposity in seasonal mammals, and consequently undergoes significant seasonal fluctuations in secretion. The seasonally breeding Siberian (Djungarian) hamster is a convenient laboratory model to study the effect of a seasonal time‐keeping clock on energy metabolism, appetite regulation and the control of adiposity. We have shown that administration of exogenous leptin at physiological doses induces significant loss of adipose tissue for short‐day housed winter‐like hamsters in which endogenous adipose tissue and leptin concentrations are already low. By contrast, long‐day housed hamsters with high adipose tissue reserves are refractory to the effects of leptin. This phenomenon of seasonal leptin resistance appears to be a general feature of other seasonally breeding mammals, and may reflect the operation of an annual timer controlling leptin uptake and/or action on central nervous system signal transduction pathways. The mobilization of fat by leptin in short‐day housed hamsters is not associated with changes in expression in either anorexic or anabolic peptides expressed in leptin‐receptor rich structures in the arcuate region of the hypothalamus, and suggests that leptin may target other structures. These data contrast with studies, which show that homeostatic mechanisms in response to feed‐restriction induce changes in hypothalamic peptides in a similar manner to nonphotoperiodic species. Thus, the long‐term seasonal regulation of body weight set point and leptin feedback may operate through separate pathways to those responsible for acute responses to food restriction.
Therapeutic Perspectives for Melatonin Agonists and Antagonists
Authors: Delagrange P. , Atkinson J. , Boutin J. A. , Casteilla L. , Lesieur D. , Misslin R. , Pellissier S. , Pénicaud L. , Renard P.
Published: May 2003

Melatonin is a neurohormone synthesized in the pineal gland during the dark period in all species, including humans. The diversity and differences in melatonin receptor distribution in the brain and extracerebral organs suggest multiple functional roles for melatonin. Administration of melatonin agonists reduces neophobia and treatment with a melatonin antagonist during the dark period reverses the anxiolytic‐like effect of endogenous melatonin. Chronic treatment with agonists prevents various perturbations induced by chronic mild stress. Melatonin in vivo directly constricts cerebral arterioles in rats and decreases the lower limit of cerebral blood flow autoregulation, suggesting that melatonin may diminish the risk of hypoperfusion‐induced cerebral ischemia. At the extracerebral level, melatonin regulates intestinal motility in rats. The intestinal postprandial motor response is shorter in the dark phase than in the light phase and this reduction is reversed in animals pretreated with a melatonin antagonist. Moreover, melatonin reduces the duration of cholecystokinin excitomotor effect. Endogenous melatonin may modulate intestinal motility to coordinate intestinal functions such as digestion and transit and control the metabolism of the animal. An adipocyte melatonin binding site may also participate in this control. Melatonin is involved in a wide range of physiological functions. The question remains as to whether evolution, adaptation and diurnal life have modified the physiological role of melatonin in humans. Moreover, the functional role of each of the receptor subtypes has to be characterized to design selective ligands to treat specific diseases.
Melatonin: From Seasonal to Circadian Signal
Authors: Pévet P.
Published: May 2003

In 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
Becoming a success story: how boys who have molested children talk about treatment
Authors: LAWSON L.
Published: May 2003

This grounded theory study was designed to generate a mid‐range theory of treatment from the perspective of boys who have molested children and undergone outpatient treatment. Data included information from seven boys’ charts, their written responses to open‐ended questions, and audio‐taped interviews. The interviews generated a series of statements reflecting the boys’ experiences in treatment, which were analysed by the constant comparative method. The basic social process of treatment was ‘becoming a success story’. The structural elements of becoming a success story included relapse prevention, compliance and decision‐making. The boys integrated these structural elements by talking to people they trusted, listening to what people said, and using what people said to help them do what was right. Becoming a success story took place in a context of family and community support. In its current form, this theory of treatment success can be used in practice to monitor progress through treatment.
Role changes experienced by clinical staff in relation to clients’ recovery from psychosis
Authors: FORCHUK C. , JEWELL J. , TWEEDELL D. , STEINNAGEL L.
Published: May 2003

This study investigates the subjective experiences of staff from many interdisciplinary teams working with clients in the recovery process from psychosis. The clinical staff interviewed in this study included: staff nurses, clinical nurse specialists, occupational therapists, psychologists, social workers, rehabilitation workers, recreation therapists, music therapists, psychiatrists, and lodging home operators. The purpose of this study was to examine the clinical staff's changing roles and relationships with clients recovering from psychosis. The investigation used a naturalistic qualitative design with an ethnographic method of data analysis. The participants were clinical staff working with clients about to commence treatment with clozapine or risperidone. The settings used were a tertiary‐care psychiatric hospital and a general hospital. The clinical staff members who participated in the study were interviewed every 3 months. In the initial interview, members of the clinical staff were asked about their knowledge regarding the new medication and their role in the decision to try the new medication. In all the interviews, clinical staff members were asked about how the recovery process was progressing with the client. Data regarding clinical staff fears related to the client's situation, changes in their relationships with the client and the client's family, and what they perceived to be current rehabilitation implications, were collected. Some of the clinical staff roles that evolved during the recovery process were: health teacher; advocate; counsellor; and support person.
Risk assessment and management of patients whom self‐neglect: a ‘grey area’ for mental health workers
Authors: GUNSTONE S.
Published: May 2003

This study explores the perceptions and experiences of community mental health workers who assess and manage the risk of self‐neglect and severe self‐neglect in people with serious mental health problems. The initial literature review demonstrated a lack of material on this specific subject. Semi‐structured interviews were undertaken with seven community mental health workers who met the criteria of being knowledgeable, skilled and credible practitioners. Data analysis was completed using thematic content analysis. Findings suggest that community mental health workers are operating in a number of areas where there is a distinct lack of clarity –‘The Grey Areas’. The most important of these were the tolerance of workers to situations of self‐neglect/severe self‐neglect, policies, procedures and legislation, and definitions of self‐neglect/severe self‐neglect. The workers dealt with this lack of clarity by completing a detailed risk assessment, which then enabled them to manage the risk. However, the need to balance the safety needs of clients against their need to be treated as autonomous individuals presented a major dilemma for workers.
‘One flew over the psychiatric unit’: mental illness and the media
Authors: ANDERSON M.
Published: May 2003

Media representation of mental illness has received growing research attention within a variety of academic disciplines. Cultural and media studies have often dominated in this research and discussion. More recently healthcare professionals have become interested in this debate, yet despite the importance of this subject only a selection of papers have been published in professional journals relating to nursing and healthcare. This paper examines the way in which mental illness in the United Kingdom is portrayed in public life. Literature from the field of media studies is explored alongside the available material from the field of mental healthcare. Three main areas are used to put forward an alternative approach: film representation and newspaper reporting of mental illness; the nature of the audience; and finally the concept of myth. The paper concludes by considering this approach in the context of current mental health policy on mental health promotion.
Interventions with family caregivers for people with dementia: efficacy problems and potential solution
Authors: CARRADICE A. , BEAIL N. , SHANKLAND M. C.
Published: May 2003

Family members are increasingly caring for relatives with dementia at home. It is well recognized that this is a stressful experience for carers. Treatment approaches that aim to alleviate this stress were introduced in the 1970s and later research began to evaluate their efficacy. Early studies using subjective ratings of satisfaction and usefulness demonstrated encouraging results. However, later studies using standardized measures of distress and burden, have not been able to demonstrate efficacy in a convincing way. There have been some positive significant changes; however, most findings have been poor, inconsistent and equivocal. This may be accounted for by the poor methodological rigour diluting the positive potential benefits of interventions for carers. This paper suggests that in order for the efficacy research to evolve, there needs to be a change in direction. It is vital that instead of repeating ‘more of the same’ studies, researchers need to prioritize the use of theoretically driven interventions and research design. This factor alone could provide the framework to influence the methodological issues that potentially dilute the demonstration of treatment efficacy. Without clearer evidence from research, guidance for practitioners about treatment for carers is ambiguous.
The role of a mental health consumer in the education of postgraduate psychiatric nursing students: the students’ evaluation
Authors: HAPPELL B. , ROPER C.
Published: May 2003

Recent Australian Government policy reflects the integral nature of active consumer participation to the planning and delivery of mental health services. The effectiveness of consumer participation in improving mental health services has received some attention in the literature. Commonwealth Government funding enabled the development of a partnership between the Centre for Psychiatric Nursing Research and Practice and the Melbourne Consumer Consultants’ Group. The successful application enabled the employment of a mental health consumer as an academic staff member of the Centre for Psychiatric Nursing Research and Practice. One important aspect of this role involved the mental health consumer teaching a consumer perspective to postgraduate psychiatric nursing students. The primary aim was to increase the students’ awareness of and sensitivity to greater consumer participation within the mental health arena. This paper presents the results of an evaluation of the consumer academic role in teaching within the Postgraduate Diploma in Advanced Clinical Nursing (Psychiatric Nursing). An evaluation form was distributed to students (n = 21) on completion of the semester. The findings suggest the experience was considered beneficial to students and was impacting significantly on their current practice. This project supports the value of consumer participation in the education of mental health professionals.
Patient satisfaction with psychiatric services provided by a Melbourne tertiary hospital emergency department
Authors: SUMMERS M. , HAPPELL B.
Published: May 2003

The mainstreaming of psychiatric services within the general healthcare system has created fundamental changes to the manner in which patients access acute psychiatric services. This change was intended to reduce the stigma associated with psychiatric diagnosis and therefore contribute to improved treatment outcomes for patients. The aim of this paper is to discuss the results of a study designed to ascertain the level of psychiatric patient satisfaction with the services received in the emergency department of a Melbourne metropolitan hospital. The results indicate a high level of satisfaction, particularly with the availability of staff with psychiatric qualifications and experience to provident treatment, support and care. The major areas of dissatisfaction identified by patients included: lengthy waiting times, lack of privacy in the triage area and negative attitudes of general staff. These findings support the argument from the literature for psychiatric consultancy services to be available in the emergency department, and further identifies the need for triage guidelines to be tailored to the needs of mental health patients and for emergency department triage staff to be appropriately educated to adequately triage these patients.
Impact of caregiving: listening to the voice of informal caregivers
Authors: SAWATZKY J. E. , FOWLER‐KERRY S.
Published: May 2003

Long‐term care of the elderly and the disabled rests on a vast network of informal caregivers. This qualitative study examined the effects of caregiving on the health and wellbeing of a small, non‐representative sample of urban women caregivers. These 11 informants participated in two interviews. Health was conceptualized in a holistic manner, consistent with the view of the World Health Organization and Health Canada. The caregiving experience, as described in this study, was life changing and consuming. Analysis revealed that the domain of caregiving could be captured by three dominant themes: loss and grieving; adapting and coping; and the short‐ and long‐term impact. The consistency in the findings and policy recommendations of studies of informal caregiving begs the question: when will caregivers finally be heard?
Manipulation: description, identification and ambiguity
Authors: BOWERS L.
Published: May 2003

The word manipulation is frequently applied to some of the difficult‐to‐manage behaviours of the personality‐disordered patient. However, the term is rarely defined, and a review of both the clinical and research literature shows that little has been written about its definition and identification, let alone its clinical management in both in‐ and outpatient settings. Recent empirical work conducted with nurses in forensic settings has demonstrated the range of behaviours that professionals refer to as ‘manipulative’, thus clarifying the use of the term and allowing the provision of a more precise definition. The scope of manipulation in everyday life, management practice and politics is perhaps relatively small, although manipulation can occur in all areas of human activity. Social behaviour is doubly ambiguous with respect to judgements of manipulation, as such judgements involve a moral evaluation combined with the identification of deception on the basis of little or partial evidence. The implications of this social ambiguity for clinical psychiatric practice are that professionals need to guard themselves from two polar faults: seeing manipulation everywhere; or being blind to its presence. In order to achieve a cautious moderation, staff need to hold both alternatives in mind at all times.
Manipulation: searching for an understanding
Authors: BOWERS L.
Published: May 2003

Manipulative behaviour is one of the reasons why some psychiatric professionals dislike personality‐disordered (PD) patients and dislike working with them. Being manipulated arouses strong negative emotions towards the manipulator and can have severe repercussions on the ability to care for or treat those suffering from personality disorders. In order for practitioners to cope with manipulative behaviour and manage their emotional responses towards it, it is necessary to find ways to understand or construe that behaviour, so that moral condemnation and rejection of the patient can be avoided. This article offers a summary of three such methods of interpreting manipulation which are to be found in the literature: manipulation as normal behaviour; manipulation as unconsciously motivated; and manipulation as cognitive distortion. These three viable schemes for the understanding of manipulation provide not just a means to enable a non‐judgemental approach, they also provide ways to manage that behaviour in a therapeutic manner.
The meaning of respite care to mothers of children with learning disabilities: two Irish case studies
Authors: HARTREY L. , WELLS J. S. G.
Published: May 2003

There is a growing interest in Ireland in the nature and significance of respite care for carers and those for whom they care. The relationship of individual stress with caring full time for a child who is learning disabled is well documented. Provision of respite care is seen as an important means of alleviating individual carer stress. Yet, the apparent benefits of respite care have been called into question. The present study looks at this issue within the context of respite service provision in Ireland for young people with learning disabilities. A phenomenological approach was used to explore the views of two mothers on respite care and, in particular, its personal significance for them within the context of their caring relationship for their children. The authors found that for these two mothers, whilst some of the predicted benefits of respite care were present, for example improved social activity, their use of respite care and the experience of separation initiated feelings of guilt and appeared to engender a degree of emotional stress. It is argued that providers of respite services in Ireland need to consider how they can support parents who use respite care so that they see its use as a mark of caring for their child and thereby alleviate such feelings of guilt.
Perspectives of mindfulness
Authors: HIRST I. S.
Published: May 2003

The idea and practice of mindfulness has a long history in some of the world's religions and is also articulated in a number of secular discourses. The therapeutic potential of mindfulness is now being recognized and is being researched in a diverse range of healthcare settings including mental health. Being mindful presupposes that individuals whose awareness is not impaired do have a choice in what phenomena they attend to and how they act. For the psychiatric nurse, understanding the idea and practice of mindfulness is useful for developing both trans‐cultural awareness and to recognize that personal inattention could compromise care. In terms of mental health promotion, mindfulness is worthy of consideration as an important life skill. This paper explores the notion of mindfulness from a number of perspectives. The paper does not claim to have explored all the options. The Buddhist understanding of mindfulness provides the perspective for continuity within the paper and is used to illuminate any similarities and differences with the secular discourses being considered.
Palliative care within secure forensic environments
Authors: FOWLER‐KERRY S.
Published: May 2003

The principles and philosophy of palliative care can be implemented successfully in secure forensic environments. While incarcerated, many inmates will suffer from a variety of life‐limiting illnesses requiring palliative care. There are a number of resources available for the development and implementation of programs within secure forensic environments.
English names for a world list of mammals, exemplified by species of Indochina
Authors: DUCKWORTH J. W. , PINE RONALD H.
Published: May 2003

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

1. 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

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

Spanish 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

Microsatellite 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

Population 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

Proportions 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

Microsatellite 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

Range‐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

The 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

I 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

The 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

African 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

In 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.