GeneCopoeia brand products include any possible DNA construct/plasmid in addition to an ever-growing offer of associated products and services. Here is a quick overview of the offer:

If you search for any human or murine gene (e.g. NFKB1) on the GeneCopoeia website, you will get a search result like this one displaying the available catalog products:

Mammalian expression constructs for certain genes such as human c-KIT are notorious for undergoing frequent recombinations during cloning and transformation steps in molecular biology labs. Experts suggest that certain genes are “toxic” to bacteria thus leading to a situation in which recombined plasmids are favored. While the molecular mechanisms for this toxicity may be unclear, the end result is that efforts to amplify, subclone, mutate, or make derivative vectors often result in a new plasmid with unwanted sequence errors.

Source: http://en.wikipedia.org/wiki/Agar_plate

Online science discussion forums such as ResearchGate include a variety of strategies proposed by researchers experiencing this kind of plasmid instability. Suggestions include advice such as culturing the bacteria at room temperature rather than 37°C, culturing on plates rather than in flasks, using low copy number EPI400 competent cells, picking the small colonies rather then the large ones from the LB plate, replacing the ampicillin resistance cassette to prevent satellite colonies (so you can see the small colonies), or using a Gateway vector.

But which methods work best?

Molecular biology experts have been telling us for a while that the Gateway® cloning vectors are easy-to-use, saving them significant time and effort.

Basically, the technology allows you to start with a single Open Reading Frame (ORF) and pop it into any kind of vector you want without having to think about different restriction sites in the Multiple Cloning Sites in your mammalian, bacterial, lentiviral, etc. expression vectors.