In vivo recombination of multigene pathways

This paper describes a method to allow construction of multigene pathways in yeast via homologous recombination. Existing methods for this only allow production of only tens to hundreds of clones, therefore limiting the number of mutants that could be explored for optimizing pathways. Although in vitro methods have also been reported, these are inefficient due to poor transformation efficiency of long DNA's. This new method, in contrast, is performed entirely in vivo, and in principle could allow production of thousands of variants. I'm not sure that this a sufficient improvement to allow significant improvements in natural product titres, and the authors haven't really demonstrated this efficiency yet, but nevertheless this method does add to the synthetic biologist's box of tools for creating and optimizing artificial pathways. I also can't help but thinking that all of this would easier from an in vitro synthetic biology perspective - doing away with the living organism entirely!