DH10B™ cells are highly efficient E. coli, perfect for most applications. The versatile DH10B™ genotype has the following features: lacZfor blue/white screening of recombinant clones,Elimination of mcr and A, mcrBC, mrr, and hsdRMS restriction systems to allow construction of more representative genomic libraries (1,2) A1 mutation to increase plasmid yield and quantity DH10B™ E. coli is available in both electrocompetent and chemically competent formats. The high transformation efficiency makes them ideal for generating cDNA or genomic libraries. High-efficiency transformation is seen with plasmids 150 kb in size (3). .