A kit for breeding a pig breed with resistance to the porcine transmissible gastroenteritis virus infection and application thereof. The systems includes a genetically edited protein, pAPN-sgRNA-1, pAPN-sgRNA-2, and a donor DNA. Effectively enzymatic cleavage can be made in two target sites of a pAPN gene by the gene editing protein. By replacing the fragment to be site-directed modified located between two target sites with donor DNA, a codon encoding tryptophan at position 737 in pAPN protein can be mutated to a codon encoding alanine, thereby achieving precise mutation of tryptophan to alanine at position 737 in a pAPN protein. The systems can avoid disruption or alteration of the normal expression of other amino acids in pAPN protein, therefore, the present invention maximally retains the physiological activity function of pAPN protein on the basis of resisting TGEV infection.

A genetically modified non-human animal comprising a genome containing an endogenous non-human ACE2 locus genetically modified to encode a complete human ACE2 gene. According to a further embodiment the genome is genetically modified to encode a second, a third, and a fourth complete human ACE2 gene, the human ACE2 gene is at least 85 percent identical to SEQ ID No: 1, the animal of is a mouse, the human ACE2 gene encodes six protein variants, an endogenous Tmprss2 gene is unmodified, a LoxP gene flanks each of a 5 and a 3 end of a nucleic acid sequence of the human ACE2 gene, and the human ACE2 gene is expressed in a lung, kidney, spleen, stomach, liver, intestine, heart, and skeletal muscle of the animal, and a cortex, striatum, middle brain, hippocampus, olfactory bulb, and cerebellum of a brain of the animal.

A kit for breeding a pig breed with resistance to the porcine transmissible gastroenteritis virus infection and application thereof. The systems includes a genetically edited protein, pAPN-sgRNA-1, pAPN-sgRNA-2, and a donor DNA. Effectively enzymatic cleavage can be made in two target sites of a pAPN gene by the gene editing protein. By replacing the fragment to be site-directed modified located between two target sites with donor DNA, a codon encoding tryptophan at position 737 in pAPN protein can be mutated to a codon encoding alanine, thereby achieving precise mutation of tryptophan to alanine at position 737 in a pAPN protein. The systems can avoid disruption or alteration of the normal expression of other amino acids in pAPN protein, therefore, the present invention maximally retains the physiological activity function of pAPN protein on the basis of resisting TGEV infection.