Abstract: The present disclosure includes methods for manipulation of the genome, to products obtained or obtainable from such methods, and uses of these products.

Abstract: This is intended to provide a technique for providing a stem cell having a mutation in both alleles (a pair of alleles). A method for producing a stem cell having a mutation in both chains of alleles which comprises: A) the step of providing a stem cell; B) the step of preventing Blm alleles from functioning in the stem cell; and C) the step of inducing mutation in the stem cell. It is also intended to provide a library of stem cells having a mutation in both chains of alleles wherein stem cells involved in the library have the mutation transferred thereinto over the entire genome.

Abstract: To comprehensively modify genome, it is intended to develop a transposition system of the copy and paste type which has an improved efficiency. This object has been achieved by the finding that an LTR retrotransposon is partly usable in a transposition system. Namely, a technique of efficiently transferring a foreign gene into a cell by using a transposon. More specifically speaking, a complete IPA element and a functional promoter sequence are found out. It is clarified that, without a combination of them, a retrotransposon cannot exert its function.