GENETIC-ANALYSIS OF 4 LINES OF METASEIULUS-OCCIDENTALIS (ACARI, PHYTOSEIIDAE) TRANSFORMED BY MATERNAL MICROINJECTION

Four lines of Metaseiulus occidentalis (Nesbitt) were transformed by m aternal microinjection. We evaluated the stability of these lines, whe ther the plasmid DNA was integrated into the nuclear genome, and condu cted tests of mode of inheritance to determine whether the transgene w as transmitted by males. The putatively transformed lines were identif ied by standard polymerase chain reaction (PCR) in the G(1) generation . After approximate to 30 generations, the lines were examined by Sout hern blot hybridization, and the plasmid probe was hybridized to uncut high-molecular-weight DNA from all 4 lines, indicating that the trans gene was associated with high-molecular-weight DNA. In restriction-dig ested Southern blots, 1 of the 4 lines (18) displayed a hybridization pattern consistent with integration of 2 plasmids into the chromosomal DNA. All 4 colonies remained positive by PCR after 150 generations. A ll 4 colonies examined by RNA-PCR for messenger RNA (mRNA) expression after 100 generations displayed PCR products consistent with transcrip tion of the introduced genetic sequences. In tests of mode of inherita nce, plasmid sequences were transmitted by line 18 males, which is con sistent with the hypothesis that the plasmid DNA is integrated into th e nuclear genome in this line.