Transgenes in F-4 pMThGH-transgenic common carp (Cyprinus carpio L.) are highly polymorphic

To gain information on the integration pattern of pMThGH-transgene, 50 tran sgenes were recovered from F-4 generation of pMThGH transgenic common carp (Cyprinus carpio L,) and 33 recovered genes were analyzed. The restriction maps of these recovered genes were constructed by digestion with five kinds of enzymes. These transgenes can be classified into 4 types according to t heir restriction maps. Only one type of transgenes maintains its original m olecular form, whereas the other three types are very different from the or iginal one and vary each other on both molecular weight and restriction map s. This implies that the sequences of most transgenes have been deleted and /or rearranged during integration and inheritance. The results of PCR ampli fication and Southern blot hybridization indicate that MThGH in Type I tran sgene keeps intact but most of its sequence has been deleted in other three types. All these results suggest that transgenes in F-4 generation of tran sgenic carp are highly polymorphic. Two DNA fragments concerning integratio n site of transgenes were cloned from recovered transgenes, and found to be homologous to the 5'UTR of beta -actin gene of common carp and mouse mRNA for receptor tyrosine kinase (RTK), respectively.