Female-Specific Lethal Genetic Systems For Use In Sterile Insect Technique (Sit): Development And Mechanism
Female-Specific Lethal Genetic Systems for use in Sterile Insect Technique (SIT):
Development and Mechanism
Michael C. Delomen
MS Genetics
ABSTRACT
Sterile insect technique (SIT) is a means of biological pest control. Sterile males are released into the environment, mates with wild females, producing no offspring. SIT is not chemical based and it is species-specific. However, it is an expensive technique. Sterilization via irradiation also sometimes affects the males’ health; such that sterile males cannot compete with wild males when seeking mates. Also, during laboratory rearing, the males may be difficult to distinguish morphologically from the females. To solve this, RIDL (release of insects carrying a dominant lethal) technique is being developed. This involves insertion of dominant lethal genes that are repressible via certain chemical substances into insects. The usual lethal genetic system is designed to be female-specific. A pest population with this kind of system can be reared in the laboratory, where the growth medium used is supplied with the repressor of the lethal genetic system. Upon reaching a desired population size, the repressor will be withdrawn from the medium, killing all females and leaving only males for SIT. These males are not sterile, but when they mate with wild females, any female offspring would inherit the lethal genetic system and die. Reduction of females would eventually lead to reproductive failure of the population. RIDL can make for easier separation of males from females during rearing. No sterilization is required; reducing expenses without reducing the reproductive ability of the released males. A system like this has been designed for Drosophila. The system involves a lethal proapoptotic gene (hid) controlled by a tetracycline-activated transactivator (tTA). The latter is then controlled by the female-specific enhancer from Drosophila yolk protein 1 (yp1)....
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