*3.4. Southern Blot Analysis*

According to the *Cppsy* genomic DNA sequence, *Bam*HI, *Eco*RI, *Nco*I, *Sma*I, and *Xma*I, which showed no recognition sites in the probed region of the *Cppsy* gene, were chosen to digest the whole genomic DNA. The probe was prepared by amplifying genomic DNA with the primers psy-F and psy-R, resulting in a 552-bp fragment of the *Cppsy* gene. The digested DNA was transferred to a Hybond-N membrane (GE Healthcare, Little Chanfont, UK) by capillary transfer and hybridized with a 32P-labelled DNA probe at both low and high stringency overnight.

After hybridization, the radioactivity of the membrane was monitored using a Storm 840 Phosphor Imaging System (Molecular Dynamics, Sunnyvale, CA, USA).
