“…Specifically, the 420 line was used to assess the reshaping of CO frequency patterns along chromosomes due to DNA methylation deficiency, axis formation, and SC mutants, as well as the positive roles of H2A.Z deposition and regional heterozygosity in CO formation ( Choi et al, 2013 ; France et al, 2021 ; Lambing et al, 2020 ; Yelina et al, 2012 ; Ziolkowski et al, 2015 ). Additionally, use of the 420 line led to the identification of HEI10, TAF4B , and SNI1 as natural modifiers of CO frequency with different Arabidopsis accessions ( Lawrence et al, 2019 ; Zhu et al, 2021 ; Ziolkowski et al, 2017 ). Moreover, the 420 seed FTL high-throughput system enabled the forward genetic screening of low or high crossover rate ( lcr or hcr ) mutants using ethyl methanesulfonate mutagenesis ( Kim et al, 2021 ; Nageswaran et al, 2021 ).…”