複選題4. Which of the following statements about T-DNA are correct? (A) The T-DNA is the transferred DNA of the tumor-inducing (Ti) plasmid. (B) The T-DNA is bordered by 2K base-pair repeats on each end (C) Transfer is initiated at the right border and terminated at the left border and requires the vir genes of the Ti plasmid. (D) Agrobacterium vir genes expression results in generation of a mobile double- stranded T-DNA to be incorporated into the plant genome. (E) Although T-DNA integration does appear to be random, proteins involved in chromatin modification likely play some role in integration.