Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Effects of fluoxetine on functional outcomes after acute stroke (FOCUS): a pragmatic, double-blind, randomised, controlled trial

Background Results of small trials indicate that fluoxetine might improve functional outcomes after stroke. The FOCUS trial aimed to provide a precise estimate of these effects. Methods FOCUS was a pragmatic, multicentre, parallel group, double-blind, randomised, placebo-controlled trial done at 103 hospitals in the UK. Patients were eligible if they were aged 18 years or older, had a clinical stroke diagnosis, were enrolled and randomly assigned between 2 days and 15 days after onset, and had focal neurological deficits. Patients were randomly allocated fluoxetine 20 mg or matching placebo orally once daily for 6 months via a web-based system by use of a minimisation algorithm. The primary outcome was functional status, measured with the modified Rankin Scale (mRS), at 6 months. Patients, carers, health-care staff, and the trial team were masked to treatment allocation. Functional status was assessed at 6 months and 12 months after randomisation. Patients were analysed according to their treatment allocation. This trial is registered with the ISRCTN registry, number ISRCTN83290762. Findings Between Sept 10, 2012, and March 31, 2017, 3127 patients were recruited. 1564 patients were allocated fluoxetine and 1563 allocated placebo. mRS data at 6 months were available for 1553 (99·3%) patients in each treatment group. The distribution across mRS categories at 6 months was similar in the fluoxetine and placebo groups (common odds ratio adjusted for minimisation variables 0·951 [95% CI 0·839–1·079]; p=0·439). Patients allocated fluoxetine were less likely than those allocated placebo to develop new depression by 6 months (210 [13·43%] patients vs 269 [17·21%]; difference 3·78% [95% CI 1·26–6·30]; p=0·0033), but they had more bone fractures (45 [2·88%] vs 23 [1·47%]; difference 1·41% [95% CI 0·38–2·43]; p=0·0070). There were no significant differences in any other event at 6 or 12 months. Interpretation Fluoxetine 20 mg given daily for 6 months after acute stroke does not seem to improve functional outcomes. Although the treatment reduced the occurrence of depression, it increased the frequency of bone fractures. These results do not support the routine use of fluoxetine either for the prevention of post-stroke depression or to promote recovery of function. Funding UK Stroke Association and NIHR Health Technology Assessment Programme

G₂ chromosomal radiosensitivity in childhood and adolescent cancer survivors and their offspring

It is increasingly recognised that individual risk of cancer may be related to genetically determined differences in the ability of cells to identify and repair DNA damage. Cell cycle based assays of chromosomal radiosensitivity provide the greatest power for discriminating differences in response to DNA damage and it has been suggested that individuals who are genetically susceptible to cancer show increased chromosomal radiosensitivity. The relationship between chromosomal radiosensitivity and early onset cancer was investigated in a population of Danish survivors of childhood and adolescent cancer and a control group comprising of their partners using the G₂ assay of chromosomal radiosensitivity. Heritability was also examined in the offspring. No significant differences in radiosensitivity profiles were found between partner controls and either the cancer survivors or offspring. However, when compared to the Westlakes Research Institute control population, significant differences were observed with the cancer survivors (P = 0.002) and offspring (P < 0.001), supporting an association of chromosomal radiosensitivity with cancer predisposition. Heritability studies suggested the majority of phenotypic variance of chromosomal radiosensitivity was attributable to a putative major gene locus with dominant effect. Since G2 chromosomal radiosensitivity indirectly measures the ability of cells to repair DNA damage induced by ionising radiation exposure, variants in DNA repair genes may explain inter-individual variation observed. Sixteen polymorphisms in nine genes from four DNA repair pathways were investigated. Genotype frequencies at the Asp148Glu polymorphism were associated with childhood cancer in survivors. Analysis of variance and FBAT analysis suggested significant associations at both the Thr241Met and Ser326Cys polymorphism sites with G₂ radiosensitivity, but neither remained significant after multiple-test adjustment. This study invites further exploration of the predictive capacity of G₂ chromosomal radiosensitivity in cancer predisposition. Clearly, further work is needed to correlate radiosensitivity with genetic polymorphisms, which may underlie cancer susceptibility and variation in radiosensitivity

The heritability of G2 chromosomal radiosensitivity and its association with cancer in Danish cancer survivors and their offspring

PURPOSE: To investigate the relationship between chromosomal radiosensitivity and early-onset cancer under age 35 years and to examine the heritability of chromosomal radiosensitivity. MATERIALS AND METHODS: Peripheral blood lymphocytes were cultured for 72 hours prior to being irradiated with 0.5 Gy, 300 kV X-rays. Colcemid was added to cultures 30 minutes post-irradiation. Cultures were harvested 90 minutes post-irradiation and analysed for chromatid gaps and breaks. Heritability was estimated using Sequential Oligogenic Linkage Analysis Routines (SOLAR) software and by segregation analysis. RESULTS: Elevated radiosensitivity was seen for 7 out of 29 (24.1%) cancer survivors, 3 out of 29 (10.3%) partners and 10 out of 53 (20.8%) offspring. Although the proportion of individuals displaying enhanced radiosensitivity was twice as high in both the cancer survivor and offspring groups than the partner controls, neither reached statistical significance. Heritability analysis of the radiosensitive phenotype suggested 57.9 – 78.0% of the variance could be attributed to genetic factors. CONCLUSIONS: An association between G(2) chromosomal radiosensitivity and childhood and young adult cancer is suggested but was not statistically significant. In contrast, there is strong evidence for heritability of the radiosensitive phenotype. The cancer survivors included a broad range of malignancies and future studies should focus on specific cancers with known or likely faults in deoxyribonucleic acid (DNA) damage recognition and repair mechanisms