Both of which are viable. The Roc2KG P element insertion is within the large intron, while the Roc2pBac piggyBac insertion is in a smaller intron upstream of the first protein-coding exon (Fig. 7A). RT-PCR analysis of embryonic mRNA (from mating homozygous males and virgin females) revealed that the Roc2KG allele expresses no detectable mRNA, while the Roc2pBac allele expresses a reduced amount of