Cells are constantly bombarded with mutagens, both endogenous and exogenous in origin. Endogenous sources of mutation include reactive oxygen species formed during aerobic respiration, replication errors by DNA polymerase, and spontaneous deamination and depurination (Jackson 2009). Exogenous sources of mutation include UV and ionizing radiation, aflatoxins, and polycyclic aromatic hydrocarbons...
A unique, permanent root-growth arrest phenotype was observed in UV-B irradiated Arabidopsis thaliana roots lacking the DNA damage response kinase ATR. Segregation analysis suggests the dependence of this phenotype on another, unidentified gene, termed ursu. High-throughput sequencing technologies were used to map and identify the causal ursu mutation. Illumina HiSeq...