Accelerated Recruitment of New Brain Development Genes into the Human Genome

How the human brain evolved has attracted tremendous interests for decades. Motivated by case studies of primate-specific genes implicated in brain function, we examined whether or not the young genes, those emerging genome-wide in the lineages specific to the primates or rodents, showed distinct spatial and temporal patterns of transcription compared to old genes, which had existed before primate and rodent split. We found consistent patterns across different sources of expression data: there is a significantly larger proportion of young genes expressed in the fetal or infant brain of humans than in mouse, and more young genes in humans have expression biased toward early developing brains than old genes. Most of these young genes are expressed in the evolutionarily newest part of human brain, the neocortex. Remarkably, we also identified a number of human-specific genes which are expressed in the prefrontal cortex, which is implicated in complex cognitive behaviors. The young genes upregulated in the early developing human brain play diverse functional roles, with a significant enrichment of transcription factors. Genes originating from different mechanisms show a similar expression bias in the developing brain. Moreover, we found that the young genes upregulated in early brain development showed rapid protein evolution compared to old genes also expressed in the fetal brain. Strikingly, genes expressed in the neocortex arose soon after its morphological origin. These four lines of evidence suggest that positive selection for brain function may have contributed to the origination of young genes expressed in the developing brain. These data demonstrate a striking recruitment of new genes into the early development of the human brain.</p

Chromosomal Redistribution of Male-Biased Genes in Mammalian Evolution with Two Bursts of Gene Gain on the X Chromosome

Mammalian X chromosomes evolved under various mechanisms including sexual antagonism, the faster-X process, and meiotic sex chromosome inactivation (MSCI). These forces may contribute to nonrandom chromosomal distribution of sex-biased genes. In order to understand the evolution of gene content on the X chromosome and autosome under these forces, we dated human and mouse protein-coding genes and miRNA genes on the vertebrate phylogenetic tree. We found that the X chromosome recently acquired a burst of young male-biased genes, which is consistent with fixation of recessive male-beneficial alleles by sexual antagonism. For genes originating earlier, however, this pattern diminishes and finally reverses with an overrepresentation of the oldest male-biased genes on autosomes. MSCI contributes to this dynamic since it silences X-linked old genes but not X-linked young genes. This demasculinization process seems to be associated with feminization of the X chromosome with more X-linked old genes expressed in ovaries. Moreover, we detected another burst of gene originations after the split of eutherian mammals and opossum, and these genes were quickly incorporated into transcriptional networks of multiple tissues. Preexisting X-linked genes also show significantly higher protein-level evolution during this period compared to autosomal genes, suggesting positive selection accompanied the early evolution of mammalian X chromosomes. These two findings cast new light on the evolutionary history of the mammalian X chromosome in terms of gene gain, sequence, and expressional evolution.</p

Is behavioural activation effective in the treatment of depression in young people? : A systematic review and meta-analysis

PURPOSE: Depression is currently the leading cause of illness and disability in young people. Evidence suggests that behavioural activation (BA) is an effective treatment for depression in adults but less research focuses on its application with young people. This review therefore examined whether BA is effective in the treatment of depression in young people. METHODS: A systematic review (International Prospective Register of Systematic Reviews reference: CRD42015020453), following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, was conducted to examine studies that had explored behavioural interventions for young people with depression. The electronic databases searched included the Cochrane Library, EMBASE, MEDLINE, CINAHL Plus, PsychINFO, and Scopus. A meta-analysis employing a generic inverse variance, random-effects model was conducted on the included randomized controlled trials (RCTs) to examine whether there were overall effects of BA on the Children's Depression Rating Scale - Revised. RESULTS: Ten studies met inclusion criteria: three RCTs and seven within-participant designs (total n = 170). The review showed that BA may be effective in the treatment of depression in young people. The Cochrane risk of bias tool and the Moncrieff scale used to assess the quality of the included studies revealed a variety of limitations within each. CONCLUSIONS: Despite demonstrating that BA may be effective in the treatment of depression in young people, the review indicated a number of methodological problems in the included studies meaning that the results and conclusions should be treated with caution. Furthermore, the paucity of studies in this area highlights the need for further research. PRACTITIONER POINTS: Currently BA is included within National Institute for Health and Clinical Excellence (NICE, 2009) guidelines as an evidence-based treatment for depression in adults with extensive research supporting its effectiveness. It is important to investigate whether it may also be effective in treating young people. Included studies reported reductions in depression scores across a range of measures following BA. BA may be an effective treatment of depression in young people

Transition of care for adolescents from paediatric services to adult health services

Background There is evidence that the process of transition from paediatric (child) to adult health services is often associated with deterioration in the health of adolescents with chronic conditions.Transitional care is the term used to describe services that seek to bridge this care gap. It has been defined as ‘the purposeful, planned movement of adolescents and young adults with chronic physical and medical conditions from child-centred to adult-oriented health care systems’. In order to develop appropriate services for adolescents, evidence of what works and what factors act as barriers and facilitators of effective interventions is needed. Objectives To evaluate the effectiveness of interventions designed to improve the transition of care for adolescents from paediatric to adult health services. Search methods We searched The Cochrane Central Register of Controlled Trials 2015, Issue 1, (including the Cochrane Effective Practice and Organisation of Care Group Specialised Register), MEDLINE, EMBASE, PsycINFO, and Web of Knowledge to 19 June 2015. We also searched reference lists of included studies and relevant reviews, and contacted experts and study authors for additional studies. Selection criteria We considered randomised controlled trials (RCTs), controlled before- and after-studies (CBAs), and interrupted time-series studies (ITSs) that evaluated the effectiveness of any intervention (care model or clinical pathway), that aimed to improve the transition of care for adolescents from paediatric to adult health services. We considered adolescents with any chronic condition that required ongoing clinical care, who were leaving paediatric services and going on to receive services in adult healthcare units, and their families. Participating providers included all health professionals responsible for the care of young people

Chromosomal Redistribution of Male-Biased Genes in Mammalian Evolution with Two Bursts of Gene Gain on the X Chromosome

Two bursts of gene gains occurred on the mammalian X chromosome contribute to an age-dependent chromosomal distribution of male-biased genes

Additional file 2: Table S1. of New genes drive the evolution of gene interaction networks in the human and mouse genomes

General characteristics of GGI networks. (PDF 91 kb

Additional file 6: Figure S4. of New genes drive the evolution of gene interaction networks in the human and mouse genomes

PPI network topological patterns of mouse genes in relation to divergence times. (PDF 146 kb