Recombineering is genetic engineering mediated by homologous recombination proteins that incorporate designed DNA changes into a target DNA molecule. In bacterial systems, recombination functions are commonly supplied by bacteriophage-derived proteins, and sequence homology between the introduced DNA and the target determines the location of the modification ^[1][2]. The target may be a chromosome, a plasmid, or a bacterial artificial chromosome. Donor substrates can consist of single-stranded oligonucleotides or double-stranded DNA, depending on the recombination system and the intended change. In the lambda Red system, Exo processes double-stranded DNA ends, Beta promotes single-strand annealing, and Gam inhibits host RecBCD activity ^[3]. Recombineering can generate substitutions, insertions, deletions, and larger rearrangements. Its outcome depends on donor–target homology, substrate processing, DNA replication, and host repair activities, with screening or selection identifying the resulting modified molecules or cells ^[1][2][4].