DNA extraction and cloning of genomic clones of Crr1a alleles

Genomic DNA was isolated using a DNeasy Plant Mini Kit (Qiagen, Germany). Amplification was carried out using Ex Taq HS polymerase (TaKaRa Bio, Japan) as follows: initial denaturation at 94°C was performed for 2 min followed by 30 cycles of amplification, including 10 s at 94°C, 30 s at 58°C, and 6 min at 72°C. The PCR product was ligated into the XL-TOPO vector (Thermo Fisher Scientific, USA) according to the manufacturer’s instructions. At least three clones were sequenced to verify the sequence.