Figure 1: Genomic modifications through BACs and TALEN. (a) The recombination of the BAC and a transgene (GFP and the antibiotic resistance gene kanamycin) leads to a modified BAC which is then randomly integrated into the DNA after microinjection into the male pronucleus. (b) The customized TALEN, specific to the sequence of interest, is constructed by PCR and digestion-ligation of hexamers that are cloned into the TALEN backbone. Subsequently, the TALEN is transcripted into RNA followed by the microinjection of the RNA into the cytoplasm of the zygote simultaneous to the injection of the GFP containing targeting vector into the pronucleus. This results in specific integration of the GFP via homologous recombination generating a knock-in locus.