This article is fear mongering with incomplete information. There are huge problems with the current techniques we use to introduce DNA into cell lines of all

This article is fear mongering with incomplete information. There are huge problems with the current techniques we use to introduce DNA into cell lines of all kinds (human or other mammals). For instance, the virus techniques he describes for inserting DNA cannot control where the DNA lands in the genome. Thus, you may end up with a cell that seems to have the properties you are after, but it acquired those traits through disrupting or activating a normal gene, thus confounding your results. Alternatively, you may be comparing cell lines with viral insertions and would ideally like the expression of the inserted genes to be similar (so that you can fairly compare their effects). These and other problems would be solved by having cell lines with known insertion locations. Whether this is best achieved by adding a new chromosome to these lines or engineering a precise "landing spot" in an existing chromosome is up for debate.