Abstract
Two interstrain crosses, YH×M and YH×Z, were done using the markers of plaque morphology and IDU (5-iodo-2′-deoxyuridine) resistance, and the recombination frequencies of 14.1 and 15.2 were obtained, respectively, whose values were practically the same as inteastrain cross of YH reported previously. Furthermore, the reciprocal recombinants were obtained in equal numbers with the cross of YH×Z. Since Z strain has a unique antigenic characteristics, further analyses were carried out on the cross of YH×Z. Characterization of clones from the progeny revealed that antigenicities readily recombined with the other markers, plaque morphology or IDU resistance, but rather high recombination frequencies were obtained. Some clones having intermediate character were found with respect to plaque morphology and antigenicity. The recombinant viruses were stable in their characters except that two recombinant viruses having the intermediate character in antigenicity changed their antigenicity to one of the parents, Z, after passages in cells, and one of them yielded the virus with different plaque morphology.
