Transgenes in F₄ pMThGH-transgenic common carp (Cyprinus carpio L.) are highly polymorphic

Abstract

To gain information on the integration pattern of pMThGH-transgene, 50 transgenes were recovered from F₄ 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 their restriction maps. Only one type of transgenes maintains its original molecular form, whereas the other three types are very different from the original one and vary each other on both molecular weight and restriction maps. This implies that the sequences of most transgenes have been deleted and/or rearranged during integration and inheritance. The results of PCR amplification and Southern blot hybridization indicate thatMThGH in Type I transgene keeps intact but most of its sequence has been deleted in other three types. All these results suggest that transgenes in F₄ generation of transgenic carp are highly polymorphic. Two DNA fragments concerning integration site of transgenes were cloned from recovered transgenes, and found to be homologous to the 5′UTR ofβ-actin gene of common carp and mouse mRNA for receptor tyrosine kinase (RTK), respectively.