System and method for genome editing based on c2c1 nucleases

A genome editing system for site-directed modification of a target sequence in the genome of a cell, comprising at least one of the following i) to v):

• i) a C2c1 protein or variant thereof, and a guide RNA;
• ii) an expression construct comprising a nucleotide sequence encoding a C2c1 protein or variant thereof, and a guide RNA;
• iii) a C2c1 protein or variant thereof, and an expression construct comprising a nucleotide sequence encoding a guide RNA;
• iv) an expression construct comprising a nucleotide sequence encoding a C2c1 protein or variant thereof, and an expression construct comprising a nucleotide sequence encoding a guide RNA;
• v) an expression construct comprising a nucleotide sequence encoding a C2c1 protein or variant thereof and a nucleotide sequence encoding a guide RNA;
• wherein the guide RNA is capable of forming complex with the C2c1 protein or variant thereof and targeting the C2c1 protein ortholog or variant thereof to the target sequence in the cell genome.