pJmammalian expression vectors constitute the latest offering in the expression-vector family. Along with pJexpress bacterial expression vectors, the pJmammalian family of vectors are free for gene-synthesis customers and provide the flexibility of working with expression vectors that are not constrained by intellectual property restrictions. pJmammalian vectors offer equal or higher levels of protein expression than a pCDNA3.1 vector when using the same insert. Customers may choose from blasticidin, hygromycin, neomycin, puromycin, or zeocin resistance markers.