Saliva is a non-invasive, easily accessible tissue, which is regularly collected in large epidemiological studies to examine genetic questions. Recently, it is becoming more common to use saliva to ...assess DNA methylation. However, DNA extracted from saliva is a mixture of both bacterial and human DNA derived from epithelial and immune cells in the mouth. Thus, there are unique challenges to using salivary DNA in methylation studies that can influence data quality. This study assesses: (1) quantification of human DNA after extraction; (2) delineation of human and bacterial DNA; (3) bisulfite conversion (BSC); (4) quantification of BSC DNA; (5) PCR amplification of BSC DNA from saliva and; (6) quantitation of DNA methylation with a targeted assay. The framework proposed will allow saliva samples to be more widely used in targeted epigenetic studies.
To reconstruct the evolutionary origin of multicellular animals from their unicellular ancestors, the genome sequences of diverse unicellular relatives are essential. However, only the genome of the ...choanoflagellate Monosiga brevicollis has been reported to date. Here we completely sequence the genome of the filasterean Capsaspora owczarzaki, the closest known unicellular relative of metazoans besides choanoflagellates. Analyses of this genome alter our understanding of the molecular complexity of metazoans' unicellular ancestors showing that they had a richer repertoire of proteins involved in cell adhesion and transcriptional regulation than previously inferred only with the choanoflagellate genome. Some of these proteins were secondarily lost in choanoflagellates. In contrast, most intercellular signalling systems controlling development evolved later concomitant with the emergence of the first metazoans. We propose that the acquisition of these metazoan-specific developmental systems and the co-option of pre-existing genes drove the evolutionary transition from unicellular protists to metazoans.
ABSTRACT
Major Axis‐I disorders including major depressive disorder (MDD), bipolar disorder (BD), anxiety disorder, and schizophrenia are associated with a host of aberrations in the way social ...stimuli are processed. Face perception tasks are often used in neuroimaging research of emotion processing in both healthy and patient populations, and to date, there exists a mounting body of evidence, both behavioral and within the brain, indicating that emotional faces compared to neutral faces are processed abnormally by those with Axis‐I disorders relative to healthy control (HC) groups. The use of neutral faces as a “baseline control condition” is predicated on the assumption that neutral faces are processed in the same way HCs and individuals with major Axis‐I disorders. In this paper, existing fMRI studies examining the way neutral faces are processed in groups with Axis‐I disorders involving socioaffective perception are reviewed. In reviewing available studies, a consistent pattern of results demonstrated that these disorders are associated with abnormal frontolimbic activity in response to neutral faces and in particular within the amygdala and prefrontal regions such as the dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC) compared to HC groups. Specifically, increased amygdala activation was consistently reported in response to neutral faces in anxiety disorders and schizophrenia. Abnormal medial PFC activity was reported in patients with MDD, and patients with BD exhibit decreased activity in the DLPFC and ACC relative to HCs. In addition, specific suggestions to overcome these obstacles with new research and additional analyses are discussed.
Neural Correlates of Epigenesis Canli, Turhan; Qiu, Maolin; Omura, Kazufumi ...
Proceedings of the National Academy of Sciences - PNAS,
10/2006, Letnik:
103, Številka:
43
Journal Article
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The effect of life stress on depression is moderated by a repeat length variation in the transcriptional control region of the serotonin transporter gene, which renders carriers of the short variant ...vulnerable for depression. We investigated the underlying neural mechanisms of these epigenetic processes in individuals with no history of psychopathology by using multimodal magnetic resonance-based imaging (functional, perfusion, and structural), genotyping, and self-reported life stress and rumination. Based on functional MRI and perfusion data, we found support for a model by which life stress interacts with the effect of serotonin transporter genotype on amygdala and hippocampal resting activation, two regions involved in depression and stress. Life stress also differentially affected, as a function of serotonin transporter genotype, functional connectivity of the amygdala and hippocampus with a wide network of other regions, as well as gray matter structural features, and affected individuals' level of rumination. These interactions may constitute a neural mechanism for epigenetic vulnerability toward, or protection against, depression.
Williams syndrome (WS) is a genetic disorder caused by a hemizygous microdeletion on chromosome 7q11.23. WS is associated with a compelling neurocognitive profile characterized by relative deficits ...in visuospatial function, relative strengths in face and language processing, and enhanced drive toward social engagement. We used a combined functional magnetic resonance imaging (fMRI) and event-related potential (ERP) approach to examine the neural basis of social responsiveness in WS participants to two types of social stimuli, negative (fearful) and positive (happy) emotional facial expressions. Here, we report a double dissociation consistent across both methods such that WS participants exhibited heightened amygdala reactivity to positive (happy) social stimuli and absent or attenuated amygdala reactivity to negative (fearful) social stimuli, compared with controls. The fMRI findings indicate that atypical social processing in WS may be rooted in altered development of disparate amygdalar nuclei that subserve different social functions. The ERP findings suggest that abnormal amygdala reactivity in WS may possibly function to increase attention to and encoding of happy expressions and to decrease arousal to fearful expressions. This study provides the first evidence that the genetic deletion associated with WS influences the function of the amygdala to be particularly responsive to socially appetitive stimuli.
The position of a poly(A) site of eukaryotic mRNA is determined by sequence signals in pre-mRNA and a group of polyadenylation factors. To reveal rice poly(A) signals at a genome level, we ...constructed a dataset of 55 742 authenticated poly(A) sites and characterized the poly(A) signals. This resulted in identifying the typical tripartite cis-elements, including FUE, NUE and CE, as previously observed in Arabidopsis. The average size of the 3′-UTR was 289 nucleotides. When mapped to the genome, however, 15% of these poly(A) sites were found to be located in the currently annotated intergenic regions. Moreover, an extensive alternative polyadenylation profile was evident where 50% of the genes analyzed had more than one unique poly(A) site (excluding microheterogeneity sites), and 13% had four or more poly(A) sites. About 4% of the analyzed genes possessed alternative poly(A) sites at their introns, 5′-UTRs, or protein coding regions. The authenticity of these alternative poly(A) sites was partially confirmed using MPSS data. Analysis of nucleotide profile and signal patterns indicated that there may be a different set of poly(A) signals for those poly(A) sites found in the coding regions. Based on the features of rice poly(A) signals, an updated algorithm termed PASS-Rice was designed to predict poly(A) sites.
Trust is an important component of human social life. Within the brain, the function within a neural network implicated in interpersonal and social-cognitive processing is associated with the way ...trust-based decisions are made. However, it is currently unknown how localized structure within the healthy human brain is associated with the tendency to trust other people. This study was designed to test the prediction that individual differences in the tendency to trust are associated with regional gray matter volume within the ventromedial prefrontal cortex (vmPFC), amygdala and anterior insula. Behavioral and neuroimaging data were collected from a sample of 82 healthy participants. Individual differences in the tendency to trust were measured in two ways (self-report and behaviorally: trustworthiness evaluation of faces task). Voxel based morphometry analyses of high-resolution structural images (VBM8-DARTEL) were conducted to test for the association between the tendency to trust and regional gray matter volume. The results provide converging evidence that individuals characterized as trusting others more exhibit increased gray matter volume within the bilateral vmPFC and bilateral anterior insula. Greater right amygdala volume is associated with the tendency to rate faces as more trustworthy and distrustworthy (U-shaped function). A whole brain analysis also shows that the tendency to trust is reflected in the structure of dorsomedial prefrontal cortex. These findings advance neural models that associate the structure and function of the human brain with social decision-making and the tendency trust other people.
In this study of eight rare atypical deletion cases with Williams-Beuren syndrome (WS; also known as 7q11.23 deletion syndrome) consisting of three different patterns of deletions, compared to ...typical WS and typically developing (TD) individuals, we show preliminary evidence of dissociable genetic contributions to brain structure and human cognition. Univariate and multivariate pattern classification results of morphometric brain patterns complemented by behavior implicate a possible role for the chromosomal region that includes: 1) GTF2I/GTF2IRD1 in visuo-spatial/motor integration, intraparietal as well as overall gray matter structures, 2) the region spanning ABHD11 through RFC2 including LIMK1, in social cognition, in particular approachability, as well as orbitofrontal, amygdala and fusiform anatomy, and 3) the regions including STX1A, and/or CYLN2 in overall white matter structure. This knowledge contributes to our understanding of the role of genetics on human brain structure, cognition and pathophysiology of altered cognition in WS. The current study builds on ongoing research designed to characterize the impact of multiple genes, gene-gene interactions and changes in gene expression on the human brain.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The language that scientists use to frame biological invasions may reveal inherent bias-including how data are interpreted. A frequent critique of invasion biology is the use of value-laden language ...that may indicate context bias. Here we use a systematic study of language and interpretation in papers drawn from invasion biology to evaluate whether there is a link between the framing of papers and the interpretation of results. We also examine any trends in context bias in biological invasion research. We examined 651 peer-reviewed invasive species competition studies and implemented a rigorous systematic review to examine bias in the presentation and interpretation of native and invasive competition in invasion biology. We predicted that bias in the presentation of invasive species is increasing, as suggested by several authors, and that bias against invasive species would result in misinterpreting their competitive dominance in correlational observational studies compared to causative experimental studies. We indeed found evidence of bias in the presentation and interpretation of invasive species research; authors often introduced research with invasive species in a negative context and study results were interpreted against invasive species more in correlational studies. However, we also found a distinct decrease in those biases since the mid-2000s. Given that there have been several waves of criticism from scientists both inside and outside invasion biology, our evidence suggests that the subdiscipline has somewhat self-corrected apparent biases.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Cultural context can affect how changes in self-concepts are either valued or tolerated. However, very little is currently known regarding how culture may differentially confer consequences to people ...that change their self-concepts over the course of several years. We investigated the moderating role of culture (Japan and USA) on the link between long-term (∼4 years) self-concept changes and a comprehensive set of well-being measures (hedonic, eudaimonic, and family based). We found that American’s self-concept instability was more negatively associated with one’s well-being and emotional support within one’s family than Japanese. Furthermore, Americans were particularly negatively impacted when they became less agentic and conscientious over time. One possible interpretation is that Western, individualistic cultures may discourage people from changing their identities throughout their adult life. Although American culture often espouses the sanctity of freedom, American culture may also limit people’s freedom to change how they see themselves over time.
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