Meiosis of anther culture regenerants in asparagus (Asparagus officinalis L.)

Pollen mother cells obtained from regenerated plants of asparagus (Asparagus officinalis L.), in a population composed exclusively of male plants, through the process of anther culture from the hybrid G27 X 22-8, were analyzed during meiosis. It was observed that, during theprocess of anther culture by organogenesis, the pollen mother cells of the regenerants had great genomic instability, as evidenced by disturbances in all the meiotic phases of the first and second division. Furthermore, structural chromosomal abnormalities, in addition to aneuploidy and polyploidy, were observed.<br>Foi analisada a meiose em células mãe de pólen de plantas de aspargo (Asparagus officinalis L.) de uma população composta exclusivamente de plantas masculinas, obtidas através do processo de cultura de anteras do híbrido G27 X 22-8. Foi observado que, durante o processo de cultura de anteras, via calogênese, as células mãe de pólen dos regenerantes apresentaram grande instabilidade genômica, evidenciada por irregularidades nas fases de diacinese, assim como de metáfase, anáfase, telófase da primeira e segunda divisão meiótica. Além disto, o processo originou anormalidades cromossômicas estruturais em adição às aneuploidias e poliploidias

Enhancing discovery of genetic variants for posttraumatic stress disorder through integration of quantitative phenotypes and trauma exposure information

BACKGROUND: Posttraumatic stress disorder (PTSD) is heritable and a potential consequence of exposure to traumatic stress. Evidence suggests that a quantitative approach to PTSD phenotype measurement and incorporation of lifetime trauma exposure (LTE) information could enhance the discovery power of PTSD genome-wide association studies (GWASs). METHODS: A GWAS on PTSD symptoms was performed in 51 cohorts followed by a fixed-effects meta-analysis (N = 182,199 European ancestry participants). A GWAS of LTE burden was performed in the UK Biobank cohort (N = 132,988). Genetic correlations were evaluated with linkage disequilibrium score regression. Multivariate analysis was performed using Multi-Trait Analysis of GWAS. Functional mapping and annotation of leading loci was performed with FUMA. Replication was evaluated using the Million Veteran Program GWAS of PTSD total symptoms. RESULTS: GWASs of PTSD symptoms and LTE burden identified 5 and 6 independent genome-wide significant loci, respectively. There was a 72% genetic correlation between PTSD and LTE. PTSD and LTE showed largely similar patterns of genetic correlation with other traits, albeit with some distinctions. Adjusting PTSD for LTE reduced PTSD heritability by 31%. Multivariate analysis of PTSD and LTE increased the effective sample size of the PTSD GWAS by 20% and identified 4 additional loci. Four of these 9 PTSD loci were independently replicated in the Million Veteran Program. CONCLUSIONS: Through using a quantitative trait measure of PTSD, we identified novel risk loci not previously identified using prior case-control analyses. PTSD and LTE have a high genetic overlap that can be leveraged to increase discovery power through multivariate methods.</p