Sheep FGF5 gene site-directed knockout system and application thereof

The invention discloses a sheep FGF5 gene site-directed knockout system, that is transcription activator like effector nuclease TALEN for cutting sheep FGF5 gene target sequence; the transcription activator like effector nuclease TALEN is composed of a nuclease TALEN-L for cutting the recognition module TALFGF5F and a nuclease TALEN-R for cutting the recognition module TALFGF5R; the nuclease TALEN-L is a protein coded by nucleotide shown in the SEQ ID NO.2 or SEQ ID NO.3, and the TALEN-R is the protein coded by SEQ ID NO.4 or SEQ ID NO.5. The invention provides a feasible material and method for further verifying the influences of the sheep FGF5 gene to wool length and wool quality, and simultaneously provides a new technology approach for increasing wool length and improving wool quality.