TRANSMISSION OF INJECTED DNA-SEQUENCES TO MULTIPLE EGGS OF METASEIULUS-OCCIDENTALIS AND AMBLYSEIUS-FINLANDICUS (ACARI, PHYTOSEIIDAE) FOLLOWING MICROINJECTION

The persistence of DNA injected into two species of adult female phyto seiids and its transmission to serial eggs deposited by them was asses sed by the polymerase chain reaction (PCR). The effect of DNA concentr ation on persistence and transmission was examined in Metaseiulus occi dentalis. M. occidentalis females were microinjected with plasmid DNA at three different concentrations (250, 500, 750 ng muL-1) and allowed to deposit one to five eggs before the females and their last eggs we re analyzed. Plasmid DNA was found in 82% of the females assayed and i n 70% of all the eggs analyzed (including the fifth eggs produced afte r microinjection). Transmission of DNA to multiple eggs was also exami ned in Amblyseius finlandicus. Females of this species are less trauma tized by microinjection allowing analysis of transmission over a more extended number of eggs. Females were microinjected and allowed to dep osit eggs until their death. DNA from every fifth egg was analyzed by the PCR. PCR products were amplified from 51% of the eggs and from all egg classes except the 30th egg. The persistence and presence of plas mid DNA in both eggs and females suggests that (1) maternal microinjec tion is a more efficient method for DNA delivery than traditional egg microinjection, (2) it may be possible to isolate transformants from f ewer fewer maternally-microinjected females than originally expected, and (3) maternal microinjection could be useful as a DNA delivery syst em in other phytoseiids.