Molecular analysis of P element behavior in Drosophila simulans transformants.

In this report we describe the successful transformation of Drosophila simulans with an autonomous P element from Drosophila melanogaster without the use of a selectable marker. This result demonstrates that there is no species barrier for P element transposition. Utilizing gel blotting and in situ hybridization techniques, we have monitored the behavior of newly-introduced P elements in several D. simulans transformed lines over twelve generations. In most instances, an overall increase in the number of P elements was observed. An examination of the frequency of P-element-bearing individuals in one line revealed the rapid spread of P elements through the population. Analysis of well-characterized sublines confirmed that P elements increase in number by transposition to new genomic sites. The formation of degenerate elements occurred in at least one case. These observations suggest that P elements may behave similarly in D. melanogaster and D. simulans.