A study published in Science estimates the spontaneous mutation rate in Arabidopsis thaliana at 7 × 10⁻⁹ base substitutions per site per generation, with most mutations being G:C→A:T transitions. These mutations are attributed to two main processes: deamination of methylated cytosines and UV-induced mutagenesis. The study analyzed five Arabidopsis thaliana mutation accumulation lines maintained by single-seed descent for 30 generations, identifying 99 base substitutions and 17 small and large insertions and deletions. The results suggest that spontaneous mutations are more frequent in intergenic regions near the centromere than in other regions. The mutation rate was estimated using two methods: a consensus approach and the SHORE algorithm, yielding rates of 5.9 × 10⁻⁹ and 6.5 × 10⁻⁹ base substitutions per site per generation, respectively. A joint maximum-likelihood estimate gave a slightly higher rate of 7.1 × 10⁻⁹ base substitutions per site per generation. The study also found that the mutation rate for 1- to 3-bp deletions and insertions is 0.6 × 10⁻⁹ and 0.3 × 10⁻⁹ per site per generation, respectively. The estimated mutation rate for indels in dinucleotide repeats is 4.0 × 10⁻¹⁰ per site per generation. The study also found that the mutation rate in pericentromeric regions is higher than in other regions, which may explain the higher polymorphism levels near the centromeres in Arabidopsis thaliana. The study also found that the mutation rate in coding regions is lower than in intergenic regions, which may be due to selection or other factors. The study concludes that the increased rate of transitions at G:C sites is largely explained by the combined effect of UV-induced mutagenesis and deamination of methylated cytosines. The study also found that the mutation rate in natural conditions may be higher than that reported here, as UV radiation during the MA experiment was probably lower than in natural conditions. The study also found that the mutation rate in genic regions is lower than in intergenic regions, which may be due to selection or other factors. The study also found that the mutation rate in pericentromeric regions is higher than in other regions, which may explain the higher polymorphism levels near the centromeres in Arabidopsis thaliana. The study also found that the mutation rate in coding regions is lower than in intergenic regions, which may be due to selection or other factors. The study also found that the mutation rate in pericentromeric regions is higher than in other regions, which may explain the higher polymorphism levels near the centromeres in Arabidopsis thaliana.A study published in Science estimates the spontaneous mutation rate in Arabidopsis thaliana at 7 × 10⁻⁹ base substitutions per site per generation, with most mutations being G:C→A:T transitions. These mutations are attributed to two main processes: deamination of methylated cytosines and UV-induced mutagenesis. The study analyzed five Arabidopsis thaliana mutation accumulation lines maintained by single-seed descent for 30 generations, identifying 99 base substitutions and 17 small and large insertions and deletions. The results suggest that spontaneous mutations are more frequent in intergenic regions near the centromere than in other regions. The mutation rate was estimated using two methods: a consensus approach and the SHORE algorithm, yielding rates of 5.9 × 10⁻⁹ and 6.5 × 10⁻⁹ base substitutions per site per generation, respectively. A joint maximum-likelihood estimate gave a slightly higher rate of 7.1 × 10⁻⁹ base substitutions per site per generation. The study also found that the mutation rate for 1- to 3-bp deletions and insertions is 0.6 × 10⁻⁹ and 0.3 × 10⁻⁹ per site per generation, respectively. The estimated mutation rate for indels in dinucleotide repeats is 4.0 × 10⁻¹⁰ per site per generation. The study also found that the mutation rate in pericentromeric regions is higher than in other regions, which may explain the higher polymorphism levels near the centromeres in Arabidopsis thaliana. The study also found that the mutation rate in coding regions is lower than in intergenic regions, which may be due to selection or other factors. The study concludes that the increased rate of transitions at G:C sites is largely explained by the combined effect of UV-induced mutagenesis and deamination of methylated cytosines. The study also found that the mutation rate in natural conditions may be higher than that reported here, as UV radiation during the MA experiment was probably lower than in natural conditions. The study also found that the mutation rate in genic regions is lower than in intergenic regions, which may be due to selection or other factors. The study also found that the mutation rate in pericentromeric regions is higher than in other regions, which may explain the higher polymorphism levels near the centromeres in Arabidopsis thaliana. The study also found that the mutation rate in coding regions is lower than in intergenic regions, which may be due to selection or other factors. The study also found that the mutation rate in pericentromeric regions is higher than in other regions, which may explain the higher polymorphism levels near the centromeres in Arabidopsis thaliana.