bluuebunny/crossref_metadata_2025_split huggingface dataset:
Origin and radiation of the house mouse: mitochondrial DNA phylogeny
Authors: Boursot P. , Din W. , Anand R. , Darviche D. , Dod B. , Von Deimling F. , Talwar G. P. , Bonhomme F. 
Published: December 2004

AbstractOn the basis of patterns of allele frequency variation in nuclear genes (Din et al., in press) it has been proposed that the house mouse M. musculus originated in the northern Indian subcontinent, from where it radiated in several directions to form the well‐described peripheral subspecies (M. m. domesticus, M. m. musculus and M. m. castaneus). Here we use a mitochondrial DNA (mtDNA) phylogeny to test this hypothesis and to analyse the historical and demographic events that have accompanied this differentiation. This marker also provides a powerful means to check for genetic continuity between the central and peripheral populations. We studied restriction site polymorphism of samples from India and the Middle East as well as samples from the rest of Eurasia and northern Africa. M. m. domesticus and M. m. musculus are both monophyletic for mtDNA and belong to the subspecies‐specific mtDNA lineages that have been described previously. Average nucleotide diversity is low in M. m. musculus (0.2–5%). It is not only higher in M. m. domesticus (0.7–0.9%) but the distribution of pairwise divergence is wider, and the rate of evolution in this branch appears to be higher than in M. m. musculus. The nucleotide diversity found in M. m. castaneus (0.4%) is due to the existence of two rather divergent linages with little intralineage variation. These two lineages are part of a diversified bush of the phylogenetic tree that also comprises several previously undescribed branches and includes all samples from the northern Indian subcontinent and Iran. The degree of diversity found in each of the samples from this region is high (1.2–2.4%) although they come from small geographic areas. This agrees well with the idea that the origin of the radiation was in the northern Indian subcontinent. However, as neither haplotypes on the M. m. domesticus nor on the M. m. musculus branches were found in this region, there appear to be important phylogeographic discontinuities between this central region and these peripherial subspecies. On the basis of the present result and the nuclear data (Din et al., in press), we propose that M. musculus originated in the north of the indian subcontinent. Our calibration of the evolutionary rate of mtDNA in mice suggests that the mouse settlement in this region could be as old as 900 000 years. Possibly from there, a first radiation could have reach the Middle East and the Caspian Sea, where the M. m. domesticus and M. m. musculus lineages, respectively, would have started to differentiate a few hundred thousand years ago, and from where they could have colonised the peripheral part of their ranges only recently.M. m. castaneus appears from its mtDNA to be recent offshoot of the northern Indian population. This multiple and gradual radiation ultimately led to recent peripheral secondary contacts, such as the well‐known European hybrid zone.
Origin and radiation of the house mouse: clues from nuclear genes
Authors: Din W. , Anand R. , Boursot P. , Darviche D. , Dod B. , Jouvin‐Marche E. , Orth A. , Talwar G.P. , Cazenave P.‐A. , Bonhomme F. 
Published: December 2004

AbstractAlthough quite a lot is known about the genetic structure of the polytypic species Mus musculus at the periphery of its range, the centre of origin and dispersion of the species remains unknown. To investigate the amount of genetic subdivision that occurs in the central parts of its range, we analysed the genetic variation in four new samples of mice coming from Iran, Pakistan, northern and southern India using 35 autosomal protein loci and restriction fragment length polymorphisms of three genes of the Vβ gene complex of the immune system. The variation was then compared with that found in the subspecies occupying the peripheral regions of the species range. The two samples from the northern part of the Indian subcontinent were shown to be more heterozygous than the samples from any of the other regions. They also contain the majority of the alleles that exist in the differentiated subspecies at the periphery of the species range. A neighbour‐joining analysis on Nei's genetic distances and a factorial analysis of correspondences on the allelic composition of each sample both place the Pakistani and Indian populations in a phylogenetically and genetically central position compared to the peripheral subspecies. These results suggest that the populations in this geographically central area have retained most of the ancestral polymorphisms, which in turn indicates that the Indian subcontinent is probably the cradle of the species. The nature of the genetic relationships between the various populations throughout the species range and the possibility that they form an incipient ring species are also discussed. Our results are in agreement with the classical model of geographic differentiation where genetic divergence in allopatry is considered to be the prime cause of subspecies formation that may eventually lead to partial reproductive isolation on secondary contact.
Phenotypic plasticity in age and size at maturity and its effects on the integrated phenotypic expressions of life history traits of Cardamine flexuosa (Cruciferae)
Authors: Kudoh H. , Ishiguri Y. , Kawano S. 
Published: December 2004

AbstractWe analyzed variation in phenotypic plasticity of life history traits between two Cardamine flexuosa populations based on differences in plasticity of age and size at maturity. C. flexuosa (Cruciferae) is a facultative, vernalization‐sensitive, long‐day annual, and its phenology and the phenotypic expressions of many life history traits are largely controlled by photoperiod and vernalization in natural populations. We used plants from two populations which differed in their responses to chilling and photoperiod treatments. The timing of developmental processes was changed by controlling temperature and photoperiod regimes in growth chambers. Plasticity in size at maturity was analyzed as changes in a growth trajectory using two parameters, age at maturity (Δt) and growth rate (k). Both traits showed plasticity, but differences between the populations were found mostly for Δt. Distinctive differences in size at maturity of individuals in the two populations were mainly due to different amounts of plasticity in Δt. Variations in plasticity of nine other life history traits and their associations to age and size at maturity were also analyzed. Variation for eight of the traits can be described, at least in part, as a function of age and size at maturity for both populations, and most of the variation in the total number of seeds was explained by age and size at maturity. Only age at maturity had any effect on changes in resource allocation. The nine life history traits were integrated through associated character expressions with age and size at maturity. Changes in the association between a trait and age and/or size at maturity were rather conservative compared to changes in the plasticity of a trait between the two populations. Associations with age and size at maturity are mostly explicable in terms of inherent relationships in the developmental processes, and they may limit the ecological range expansion and the adaptive evolution of plasticity in C. flexuosa. The negative correlation between reproductive allocation and age at maturity can be a cost of delaying maturation in C. flexuosa.
Ejaculate size in bushcrickets: the importance of being large
Authors: Wedell N. 
Published: December 2004

AbstractSexual size dimorphism is common in animals. Females, which often experience increased fecundity with size, are generally the larger sex. In males, the pre‐copulatory advantages of large size have been extensively investigated. However, in polyandrous species, large male size may also be advantageous after copulation due to sperm competition. Male size co‐varies with ejaculate size and increased fertilization success in many insects. Large male size can also be important for production of nuptial gifts enhancing female fecundity. In this study, the relative importance of male size for ejaculate and nuptial gift production is assessed in 20 bushcricket species (Orthoptera: Tettigoniidae). Relative male size is found to correlate with increased ejaculate size across taxa. In contrast, no association is found between relative male size and the size or quality of the nuptial gift. These findings indicate that selection for increased ejaculate volumes as a response to sperm competition may act to promote large male size in insects.
The seasonal timing of oviposition in sand lizards (Lacerta agilis): why early clutches are better
Authors: Olsson M. , Shine R. 
Published: December 2004

AbstractWe studied a population of sand lizards (Lacerta agilis) near the northern edge of the species' range in coastal Sweden. We captured, marked, released and recaptured 98 adult female lizards over 5 years. Hatchlings from 146 laboratory‐incubated clutches (1279 eggs) from field‐caught gravid females were measured, weighed, marked and released at the study site. Female sand lizards usually laid only a single clutch of 4 to 15 eggs each year, but varied considerably in the time of year at which they laid their eggs. Oviposition dates shifted between years depending on weather (basking opportunities), but the relative timing of oviposition was consistent within a given female from year‐to‐year. The first females to oviposit each year were large animals in good physical condition, that had grown rapidly in previous years. “Early” clutches were larger than “later” clutches, had higher hatching success, and tended to have higher post‐hatching survival rates. Offspring from early clutches were larger than “later” hatchlings, and differed in body proportions (probably because seasonal changes in maternal temperatures directly modified offspring phenotypes).Overall, our study documents several strong correlates of the timing of oviposition, and suggests that variation in this trait among females has strong fitness consequences, perhaps related to maternal “quality”. The correlations we observed between oviposition date and other traits that have been invoked as determinants of hatchling survival in reptiles (e.g., hatchling size, body shape, opportunities for multiple mating by the mother) suggest that hypotheses advocating simple causal connections between these traits and hatchling success should be viewed with caution.
Fluctuating asymmetry in the honey bee, Apis mellifera: effects of ploidy and hybridization
Authors: Smith D. R. , Crespi B. J. , Bookstein F. L. 
Published: December 2004

AbstractWe present a new measure of morphological asymmetry that avoids most of the statistical problems inherent in character‐by‐character analysis of size or shape. The method is an application of Procrustes analysis, which computes best‐fitting super‐positions of configurations of landmarks to the left and right sides of a single specimen. The Procrustes method combines subtle deviations in all aspects of the landmark configuration into one net asymmetry score. Directional asymmetry is separated from fluctuating asymmetry in a simple partition of a net sum‐of‐squares, and geometrical details of either component can be inspected by traditional methods of multivariate statistical analysis of landmarks.We demonstrate this method in a comparison of wing venation asymmetry in male (haploid) and female (diploid) honey bees (Apis mellifera). In addition we investigate the effects of ploidy and inter‐subspecies hybridization on asymmetry and wing venation abnormalities, using the subspecies A. m. mellifera, A. m. carnica, and the hybrid strain “Nigra”. Results suggest that while the haploid males showed a higher frequency of wing venation abnormalities and greater total asymmetry than the diploid females, most of the asymmetry difference between males and females was in the form of directional, not fluctuating, asymmetry. Hybrid females had a higher frequency of wing venation abnormalities than females of either subspecies, but there were no significant differences in the mean level of asymmetry among females of A. m. mellifera, A. m. carnica and hybrid Nigra. Hybrid males had higher absolute frequency of wing venation abnormalities and asymmetry than males of either subspecies. However the mean frequency of venation abnormalities did not differ significantly between Nigra and A. m. carnica males, and mean asymmetries were not significantly different between Nigra and A. m. mellifera males. We discuss the relationship which is assumed to exist between developmental stability and fluctuating asymmetry in light of our result.
Play Behavior in Juvenile Golden Lion Tamarins (Callitrichidae: Primates): Organization in Relation to Costs
Authors: De Oliveira Cláudia R. , Ruiz‐Miranda Carlos R. , Kleiman Devra G. , Beck Benjamin B. 
Published: December 2004

AbstractPlay is a complex behavior that is widespread among vertebrates. Despite the potential benefits for the development of social, cognitive and motor skills, play behavior has costs: energy expenditure, and the risks of injury and predation. As the fitness benefits of play are presumably to be gained as adults, we expect young animals to minimize its immediate costs. Here, we describe play behavior in golden lion tamarins (GLTs) (Leontopithecus rosalia) and test cost‐minimizing hypotheses. We collected data on play behavior and adult vigilance in nine groups (four wild and five supplemented, the latter deriving from a reintroduction) of wild‐living lion tamarins (16 infants) in Brazil. Results showed that play occupied 3.8% of the activity budget, occurred during the hottest times of the day, and was characterized by being mainly social, involving partners of different ages, and sometimes different species. We found no differences in playing time between wild and supplemented groups. The lion tamarins played less in ‘dangerous’ substrates (canopy branches and forest floor), and more in ‘safe’ substrates (large branches and vine tangles), and favored playing in the center of the group over the periphery. The reproductive animals were vigilant during 78% of the time the infants were playing, and were mostly oriented away from the playing animals. The observed organization of play behavior suggests that juvenile GLTs minimize the risk of predation and accidental injuries, but do not seem to minimize energy expenditure and the risks of social injuries. The social‐cognitive benefits acquired from experience of older partners during play may overcome the costs of the latter behavior, and because little time was spent in play, the energetic costs may be inconsequential.
The Grooming Invitation Dance of the Honey Bee
Authors: Land Benjamin B. , Seeley Thomas D. 
Published: December 2004

AbstractThe grooming invitation dance is a striking behavior in honey bee colonies that has not been extensively studied. The objectives of this study were (1) to describe the dance through video analysis, (2) to test the functional hypothesis that it is a grooming solicitation signal, and (3) to analyze the stimuli that cause its production. A worker bee producing the grooming invitation dance stands stationary and vibrates her whole body from side‐to‐side at a frequency of 4.2 ± 0.2 Hz for 9.3 ± 1.0 s. Sometimes the bee mixes bouts of body vibration with brief bouts of self‐grooming (average duration = 1.4 s). Bees that perform the grooming invitation dance have a far higher probability of being quickly groomed by a nest mate than do bees that do not perform the dance. Bees that had chalk dust puffed onto the bases of their wings produced significantly more grooming invitation dances than did control bees that received only puffs of air. This shows that it may be the accumulation of small particles at the bases of the wings that normally triggers the dance. We suggest that the evolutionary origin of this signal is self‐grooming behavior.
Genetic diversity measures of the bovine Alberes breed using microsatellites: variability among herds and types of coat colour*
Authors: Casellas J. , Jiménez N. , Fina M. , Tarrés J. , Sánchez A. , Piedrafita J. 
Published: December 2004

SummaryThe Alberes population is a native bovine breed of Catalonia with an unclear origin, which historically some authors have assumed as being composed of two different colour varieties (black and fawn). Sixteen microsatellite loci were analysed, all of them included in the AIRE2066 European Concerted Action list. Overall expected and observed heterozygosities reached values of 0.649 and 0.662, respectively. Genetic differences among black and fawn varieties were not significant (FST = 0.007), and therefore the population is a single variety with a great colour gradation. On the contrary, we detected significant genetic differences among herds (FST = 0.026; p < 0.001), showing a genetic heterogeneity over short geographical distances. The number of migrants per generation among pairs of herds oscillates between 1.46 (Roig and Freixe herds) and 5.62 (Castanyers and Roig herds). Moreover, inbreeding and bottleneck situations can be rejected. The Alberes breed has been grouped within the Cantabrian trunk, closely related to the Asturiana de la Montaña and Alistana breeds, although some other breeds may also have influenced the population along its history.
Developmental changes in calbindin‐D28k and calretinin expression in the mouse suprachiasmatic nucleus
Authors: Ikeda Masayuki , Allen Charles N. 
Published: December 2004

AbstractThe hypothalamic suprachiasmatic nucleus, the primary circadian pacemaker in mammals, and the retinohypothalamic tract, the retinal afferent fibres to the suprachiasmatic nucleus, both mature during early postnatal life. The establishment of circadian rhythms is thought to depend on input from the retina, but the mechanism remains unknown. Here we examined developmental changes in the expression of the Ca2+‐binding proteins calbindin‐D28k and calretinin in the mouse hypothalamus. Robust calbindin‐D28k immunoreactivity was observed in the dorsomedial suprachiasmatic nucleus and the supraoptic nucleus in neonatal mice (postnatal day 3). The calbindin‐D28k immunoreactivity decreased significantly in the suprachiasmatic nucleus but not in the supraoptic nucleus during postnatal days 9–15, when retinohypothalamic tract projections to the suprachiasmatic nucleus are completed. Calretinin immunoreactivity was low in the neonatal suprachiasmatic nucleus and increased with development in the ventrolateral suprachiasmatic nucleus, in parallel with the developmental reduction of calbindin‐D28k immunoreactivity observed in the dorsomedial suprachiasmatic nucleus. Developmentally stable calretinin immunoreactivity was also observed in retinohypothalamic tract fibres. Organotypic slice cultures of the suprachiasmatic nucleus were prepared from postnatal day 3 mice to examine the effect of the absence of retinohypothalamic tract inputs on developmental changes in calbindin‐D28k and calretinin expression. After 12 days in vitro, the cultured suprachiasmatic nucleus slices exhibited dense calbindin‐D28k immunoreactivity similar to neonatal mice, and calretinin immunoreactivity in the ventrolateral suprachiasmatic nucleus similar to young adult mice. These results demonstrate a developmental reduction in calbindin‐D28k expression that paralleled retinohypothalamic tract formation and a developmental increase in calretinin expression that is independent of retinohypothalamic tract connections to suprachiasmatic nucleus neurons.
The integration of cortical and behavioural dynamics during initial learning of a motor task
Authors: Serrien Deborah J. , Brown Peter 
Published: December 2004

AbstractHere we test the hypothesis that frequency and topographically specific changes in the strength of functional cortico–cortical coupling occur during the acquisition of a completely new task. To this end we studied the behavioural and cortical dynamics of a bimanual multifrequency coordination pattern during which one hand moved at twice the frequency of the other hand. This pattern represents a noninherent assignment and necessitates training before appropriate interlimb decoupling takes place. Results showed that acquisition of the multifrequency task was associated with an improved behavioural output that matched specific changes in the electroencephalogram dynamics. In particular, practice of the coordination pattern was accompanied by a decrease in coherence between the primary sensorimotor regions, and over the midline area in the alpha and beta bands, respectively, along with an increase in functional interhemispheric coupling between the prefrontal areas in the gamma band. These data suggest that the strength of cortico–cortical connectivity is adaptively modified across regions and across frequencies during early learning as the functional couplings are created and optimized for the purpose of movement execution.
Forebrain astroglial plasticity is induced following withdrawal from repeated cocaine administration
Authors: Bowers M. Scott , Kalivas Peter W. 
Published: December 2004

AbstractAstrocytes actively participate in synaptic plasticity and respond to insult or metabotropic glutamate receptor activation with increased expression of the intermediate filament glial fibrillary acidic protein (GFAP). Extended withdrawal from repeated cocaine administration induces many forms of neuroplasticity. The present study with rats utilized a 3‐week withdrawal period from daily cocaine administration (i.p.; 7 days) to investigate whether astrocytes participate in cocaine‐mediated plasticity observed in brain nuclei associated with addiction. Following the 3‐week withdrawal period, immunoblotting revealed increased GFAP expression in the prefrontal cortex (PFC) and in the shell and core compartments of the nucleus accumbens (NAshell and NAcore). Upregulation of GFAP did not occur in the striatum or in any brain region tested following shorter withdrawal times from repeated cocaine (24 h or 1 week) or following 2‐h withdrawal from an acute cocaine injection (30 mg/kg i.p.). However, GFAP expression increased following a 3‐week withdrawal from a single cocaine injection selectively in the NAshell. Cell counts revealed that astrocyte cell number increased only in the NAcore while immunoblots of a marker for immature or reactive astrocytes, vimentin, showed an increase only in the PFC following the 3‐week withdrawal. Taken together, these results suggest that altered intermediate filament expression within forebrain astrocytes may be a significant part of the plasticity occurring during withdrawal from repeated cocaine. Furthermore, the increase in GFAP may arise from regionally distinct mechanisms, with the NAcore relying more on cell proliferation while the PFC relies on a larger reactive astrocyte population.