In iGEM, most teams have inserted their Biobrick parts or devices into plasmids and have used them. It is true that there are many good points to use plasmids, for instance, it is easy to do transformation, and it is convenient to use high copy plasmid when you want to get high amount of gene expression. However, there are some bad points to use plasmids too. For example, when the reproduction starting point of plural plasmids are covered, they are unstable to coexist at the 1 cell (Fig.2.A.). Also the expression of genes which are in plasmids is sometimes leaky (Fig.2.B). Additionally, it isn’t possible to clone the fragment that over 15kb to plasmids (Fig.2.C). We summarized an advantage and a fault of the plasmids in a lower table. (Table1)

In order to solve these problems, we thought that we should create a new method to use Biobricks in a genome of E.coli. In this method, plasmids are only used as templates. We think that using this method is more convenient and safe than using plasmids. There are following reasons that we think about like that. We describe these reasons below.