RESUMO
As one of the most important applications of digitalization, intelligence, and service, the digital twin (DT) breaks through the constraints of time, space, cost, and security on physical entities, expands and optimizes the relevant functions of physical entities, and enhances their application value. This phenomenon has been widely studied in academia and industry. In this study, the concept and definition of DT, as utilized by scholars and researchers in various fields of industry, are summarized. The internal association between DT and related technologies is explained. The four stages of DT development history are identified. The fundamentals of the technology, evaluation indexes, and model frameworks are reviewed. Subsequently, a conceptual ternary model of DT based on time, space, and logic is proposed. The technology and application status of typical DT systems are described. Finally, the current technical challenges of DT technology are analyzed, and directions for future development are discussed.
RESUMO
Seven single nucleotide polymorphisms (SNPs) were identified by PCR-SSCP and sequencing in the chicken apoA5 gene in F2 chickens from an experimental cross of White Plymouth Rock x Silkies. One SNP(C-169T) located on the 5'-regulatory region, another two in the second exon were transitions of C to T (600) and T to C (635). Four SNPs in the third exon were found, which were C841G, C914T, C1142G, C1394T. The association of the polymorphisms with carcass traits was investigated. The most significant results were yielded from primer apoA3F/R: the abdominal fat weight of CC chickens were significantly higher than that of AA, AB, AC, BB and BC chickens (P<0.05); AC chickens had lower liver weight than that of AA, AB, BB, BC and CC (P<0.05); BC chickens had lower heart weight than that of BB (P<0.05).