Gene targeting and somatic cell genetics - a rebirth or a coming of age?

A number of recent advances have significantly facilitated gene targeting i n somatic cells. Gene targeting can now be performed with the same ease and efficiency in somatic cells as in murine embryonic stem cells. Rigorous ge netic analyses can therefore be applied for the first time to the large num ber of excellent human cell culture systems. These tools wilt be important in areas where rodent models do not adequately represent human biology.