SRP492880 PRJNA1082775 30-day SCNT placenta and AI placental transcriptome sequencing In order to find out the main causes of misdevelopment of cloned pig embryos, this study will help to understand the law of cloned pig embryo development and provide a new method to improve the efficiency of cloned pigs. finds out a main cause of erroneous development of cloned pig fetuses, which will be benificial for understanding the regulation of SCNT embryo development, as well as developing new methods to improve the efficiency of pig cloning.