Abstract
Mixed infections of secondary rhesus monkey kidney cells with human rotaviruses carrying rearranged genomes and with bovine rotavirus yielded a high percentage of reassortants. The genotypes of 511 plaque-purified clones raised in either MA104 or BSC-1 cells have been determined and the frequencies of different genotypes have been calculated. It was found that (i) reassortants did not emerge at random; (ii) there was non-random association of certain genes; (iii) the cell line used to isolate reassortants influenced the result, i.e. host cell factors had a selective effect on a recombinational mixture.