131 research outputs found

    The combined effect of two mutations that alter serially homologous color pattern elements on the fore and hindwings of a butterfly

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>The ability for serially homologous structures to acquire a separate identity has been primarily investigated for structures dependent on Hox gene input but is still incompletely understood in other systems. The fore and hindwings of butterflies are serially homologous structures as are the serially homologous eyespots that can decorate each of these wings. Eyespots can vary in number between fore and hindwings of the same individual and mutations of large effect can control the total number of eyespots that each of the wings displays. Here we investigate the genetics of a new spontaneous color pattern mutation, <it>Missing</it>, that alters eyespot number in the nymphalid butterfly, <it>Bicyclus anynana</it>. We further test the interaction of <it>Missing </it>with a previously described mutation, <it>Spotty</it>, describe the developmental stage affected by <it>Missing</it>, and test whether <it>Missing </it>is a mutant variant of the gene <it>Distal-less </it>via a linkage association study.</p> <p>Results</p> <p><it>Missing </it>removes or greatly reduces the size of two of the hindwing eyespots from the row of seven eyespots, with no detectable effect on the rest of the wing pattern. Offspring carrying a single <it>Missing </it>allele display intermediate sized eyespots at these positions. <it>Spotty </it>has the opposite effect of <it>Missing</it>, i.e., it introduces two extra eyespots in homologous wing positions to those affected by <it>Missing</it>, but on the forewing. When <it>Missing </it>is combined with <it>Spotty </it>the size of the two forewing eyespots decreases but the size of the hindwing spots stays the same, suggesting that these two mutations have a combined effect on the forewing such that <it>Missing </it>reduces eyespot size when in the presence of a <it>Spotty </it>mutant allele, but that <it>Spotty </it>has no effect on the hindwing. <it>Missing </it>prevents the complete differentiation of two of the eyespot foci on the hindwing. We found no evidence for any linkage between the <it>Distal-less </it>and <it>Missing </it>genes.</p> <p>Conclusion</p> <p>The spontaneous mutation <it>Missing </it>controls the differentiation of the signaling centers of a subset of the serial homologous eyespots present on both the fore and the hindwing in a dose-dependent fashion. The effect of <it>Missing </it>on the forewing, however, is only observed when the mutation <it>Spotty </it>introduces additional eyespots on this wing. <it>Spotty</it>, on the other hand, controls the differentiation of eyespot centers only on the forewing. <it>Spotty</it>, unlike <it>Missing</it>, may be under Ubx gene regulation, since it affects a subset of eyespots on only one of the serially homologous wings.</p

    Cortico-cerebellar functional connectivity and sequencing of movements in schizophrenia

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Abnormal execution of several movements in a sequence is a frequent finding in schizophrenia. Successful performance of such motor acts requires correct integration of cortico-subcortical processes, particularly those related to cerebellar functions. Abnormal connectivity between cortical and cerebellar regions with resulting cognitive dysmetria has been proposed as the core dysfunction behind many signs and symptoms of schizophrenia. The aim of the present study was to assess if these proposed abnormalities in connectivity are a unifying feature of schizophrenia, or, rather, reflect a specific symptom domain of a heterogeneous disease. We predicted that abnormal functional connectivity between the motor cortex and cerebellum would be linked with abnormal performance of movement sequencing.</p> <p>Methods</p> <p>We examined 24 schizophrenia patients (SCH) and 24 age-, sex-, and handedness-matched healthy controls (HC) using fMRI during a modified finger-tapping task. The ability to perform movement sequencing was tested using the Neurological Evaluation Scale (NES). The subjects were categorized into two groups, with (SQ+) and without (SQ-) movement sequencing abnormalities, according to the NES-SQ score. The effects of diagnosis and movement sequencing abnormalities on the functional connectivity parameters between the motor cortex and cerebellum (MC-CRBL) and the supplementary motor cortex and cerebellum (SMA-CRBL) activated during the motor task were analyzed.</p> <p>Results</p> <p>We found no effect of diagnosis on the functional connectivity measures. There was, however, a significant effect on the SQ group: SQ + patients showed a lower level of MC-CRBL connectivity than SQ- patients and healthy controls. Moreover, the level of MC-CRBL and SMA-CRBL negatively correlated with the magnitude of NES-SQ abnormalities, but with no other NES domain.</p> <p>Conclusions</p> <p>Abnormal cortico-cerebellar functional connectivity during the execution of a motor task is linked with movement sequencing abnormalities in schizophrenia, but not with the diagnosis of schizophrenia per se. It seems that specific patterns of inter-regional connectivity are linked with corresponding signs and symptoms of clinically heterogeneous conditions such as schizophrenia.</p

    Natural course of behavioral addictions: A 5-year longitudinal study

    Get PDF
    BACKGROUND: Resolving the theoretical controversy on the labeling of an increasing number of excessive behaviors as behavioral addictions may also be facilitated by more empirical data on these behavioral problems. For instance, an essential issue to the classification of psychiatric disorders is information on their natural course. However, longitudinal research on the chronic vs. episodic nature of behavioral addictions is scarce. The aim of the present study, therefore, was to provide data on prevalence, substance use comorbidity, and five-year trajectories of six excessive behaviors—namely exercising, sexual behavior, shopping, online chatting, video gaming, and eating. METHODS: Analyses were based on the data of the Quinte Longitudinal Study, where a cohort of 4,121 adults from Ontario, Canada was followed for 5 years (2006 to 2011). The response rate was 21.3%, while retention rate was 93.9%. To assess the occurrence of each problem behavior, a single self-diagnostic question asked people whether their over-involvement in the behavior had caused significant problems for them in the past 12 months. To assess the severity of each problem behavior reported, the Behavioral Addiction Measure was administered. A mixed design ANOVA was used to investigate symptom trajectories over time for each problem behavior and whether these symptom trajectories varied as a function of sex. RESULTS: The large majority of people reported having problematic over-involvement for just one of these behaviors and just in a single time period. A main effect of time was found for each problem behavior, indicating a moderately strong decrease in symptom severity across time. The time x sex interaction was insignificant in each model indicating that the decreasing trend is similar for males and females. The data also showed that help seeking was very low in the case of excessive sexual behavior, shopping, online chatting, and video gaming but substantially more prevalent in the case of excessive eating and exercising. CONCLUSIONS: The present results indicate that self-identified excessive exercising, sexual behavior, shopping, online chatting, video gaming, and/or eating tend to be fairly transient for most people. This aspect of the results is inconsistent with conceptualizations of addictions as progressive in nature, unless treated. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12888-015-0383-3) contains supplementary material, which is available to authorized users

    Quantitative Genetics, Pleiotropy, and Morphological Integration in the Dentition of Papio hamadryas

    Get PDF
    Variation in the mammalian dentition is highly informative of adaptations and evolutionary relationships, and consequently has been the focus of considerable research. Much of the current research exploring the genetic underpinnings of dental variation can trace its roots to Olson and Miller's 1958 book Morphological Integration. These authors explored patterns of correlation in the post-canine dentitions of the owl monkey and Hyopsodus, an extinct condylarth from the Eocene. Their results were difficult to interpret, as was even noted by the authors, due to a lack of genetic information through which to view the patterns of correlation. Following in the spirit of Olson and Miller's research, we present a quantitative genetic analysis of dental variation in a pedigreed population of baboons. We identify patterns of genetic correlations that provide insight to the genetic architecture of the baboon dentition. This genetic architecture indicates the presence of at least three modules: an incisor module that is genetically independent of the post-canine dentition, and a premolar module that demonstrates incomplete pleiotropy with the molar module. We then compare this matrix of genetic correlations to matrices of phenotypic correlations between the same measurements made on museum specimens of another baboon subspecies and the Southeast Asian colobine Presbytis. We observe moderate significant correlations between the matrices from these three primate taxa. From these observations we infer similarity in modularity and hypothesize a common pattern of genetic integration across the dental arcade in the Cercopithecoidea

    Assessing recent trends in high-latitude Southern Hemisphere surface climate

    Get PDF
    Understanding the causes of recent climatic trends and variability in the high-latitude Southern Hemisphere is hampered by a short instrumental record. Here, we analyse recent atmosphere, surface ocean and sea-ice observations in this region and assess their trends in the context of palaeoclimate records and climate model simulations. Over the 36-year satellite era, significant linear trends in annual mean sea-ice extent, surface temperature and sea-level pressure are superimposed on large interannual to decadal variability. However, most observed trends are not unusual when compared with Antarctic paleoclimate records of the past two centuries. With the exception of the positive trend in the Southern Annular Mode, climate model simulations that include anthropogenic forcing are not compatible with the observed trends. This suggests that natural variability likely overwhelms the forced response in the observations, but the models may not fully represent this natural variability or may overestimate the magnitude of the forced response

    One thousand plant transcriptomes and the phylogenomics of green plants

    Get PDF
    Abstract: Green plants (Viridiplantae) include around 450,000–500,000 species1, 2 of great diversity and have important roles in terrestrial and aquatic ecosystems. Here, as part of the One Thousand Plant Transcriptomes Initiative, we sequenced the vegetative transcriptomes of 1,124 species that span the diversity of plants in a broad sense (Archaeplastida), including green plants (Viridiplantae), glaucophytes (Glaucophyta) and red algae (Rhodophyta). Our analysis provides a robust phylogenomic framework for examining the evolution of green plants. Most inferred species relationships are well supported across multiple species tree and supermatrix analyses, but discordance among plastid and nuclear gene trees at a few important nodes highlights the complexity of plant genome evolution, including polyploidy, periods of rapid speciation, and extinction. Incomplete sorting of ancestral variation, polyploidization and massive expansions of gene families punctuate the evolutionary history of green plants. Notably, we find that large expansions of gene families preceded the origins of green plants, land plants and vascular plants, whereas whole-genome duplications are inferred to have occurred repeatedly throughout the evolution of flowering plants and ferns. The increasing availability of high-quality plant genome sequences and advances in functional genomics are enabling research on genome evolution across the green tree of life

    ICAR: endoscopic skull‐base surgery

    Get PDF
    n/
    • 

    corecore