The insertion of the PGK_EM7_PuDtk_bGHpA cassette created a deletion of Chromosome 6 (Genome Build 37). This deletion eliminates the DNA sequence for this microRNA. The cassette is composed of a loxP site followed by an F3 site followed by a PGK-puromycin-delta-tk cassette, a loxP site and finally an FRT site. Recombination events removed the selection cassette.