Genetic characteristics of polycistronic system‑mediated randomly‑inserted multi‑transgenes in miniature pigs and mice.

Multi‑transgenic technology is superior to single transgenic technology in biological and medical research. Multi‑transgene insertion mediated by a polycistronic system is more effective for the integration of polygenes. The multi‑transgene insertion patterns and manners of inheritance are not completely understood. Copy number quantification is one available approach for addressing this issue. The present study determined copy numbers in two multi‑transgenic mice (K3 and L3) and two multi‑transgenic miniature pigs (Z2 and Z3) using absolute quantitative polymerase chain reaction analysis. For the F0 generation, a given transgene was able to exhibit different copy number integration capacities in different individuals. For the F1 generation, the most notable characteristic was that the copy number proportions were different among pedigrees (P<0.05). The results of the present study demonstrated that transgenes within the same vector exhibited the same integration trend between the F0 and F1 generations. In conclusion, intraspecific consistency and intergenerational copy numbers were compared and the integration capacity of each specific transgene differed in multi‑transgenic animals. In particular, the copy number of one transgene may not be used to represent other transgenes in polycistronic vector‑mediated multi‑transgenic organisms. Consequently, in multi‑transgenic experimental animal disease model research or breeding, copy numbers provide an important reference. Therefore, each transgene in multi‑transgenic animals must be separately screened to prevent large copy number differences, and inconsistent expression between transgenes and miscellaneous data, in subsequent research.