Abstract: Provided is a non-LTR retrotransposon system. An isolated functional protein encoded by a retrotransposon, a nucleic acid encoding the functional protein, a nucleic acid set, a nucleic acid construct, a composition, a recombinant vector, a recombinant host cell and a kit are provided. A method for introducing an exogenous nucleic acid fragment into the genome of a host cell, a method for editing the genome of a host cell, and a method for obtaining a host cell containing an exogenous nucleic acid fragment in the genome are also provided.

Abstract: It relates to the field of molecular biology, and specifically to an isolated nuclease and the use thereof. It further specifically relates to: a nucleic acid and a nucleic acid construct encoding the nuclease, a guide RNA and a nucleic acid construct thereof, and a composition, a recombinant vector, a recombinant host cell and a kit comprising the nuclease. It further specifically relates to: a method for introducing a double-strand break into a targeting gene of a host cell, a method for deleting, replacing or inserting a targeting gene of a host cell, and a method for obtaining a host cell in which a targeting gene is deleted, replaced or inserted.