Funding for this research was provided by:
National Natural Science Foundation of China (31772552, 31941007, 31872321)
Received: 17 May 2020
Accepted: 24 February 2021
First Online: 2 March 2021
: Ethical permission to collect ear tissue samples from pigs was approved by the Institutional Animal Care and Use Committee of Shanghai Jiao Tong University. As the pig owners’ inability to write, they verbally consented that samples were taken from their pigs and used for research. All procedures in which pigs were involved were per the agreement of the Institutional Animal Care and Use Committee of Shanghai Jiao Tong University (contract no. 2011–0033).
: Not applicable.
: The authors declare that they have no competing interests.