text_1: A strong bias in the phage genome locations where the spacers were derived has been observed in many CRISPR subtypes that confer the immunity to phage.
text_2: Our results suggest that, in Escherichia coli, acquisition of new spacers largely depends on RecBCD-mediated processing of double-stranded DNA breaks occurring primarily at replication forks, and that the preference for foreign DNA is achieved through the higher density of Chi sites on the self chromosome, in combination with the higher number of forks on the foreign DNA.