A science researcher has developed a computer model of the process of dna replication in a eukaryotic cell. The model includes the following sequence of bases in one strand of the dna molecule. Aacctggccatggacctttatataaactaggat the researcher wants to revise the model to show the transcription of dna to form mrna. Scientists have observed that the same gene may produce several different mrna molecules. How could the researcher's model show this variety of mrna molecules? identify the stage that introduces this variety.