Dominant lethal Aedes aegypti mosquito

OX513A(My1) contains two new traits: (i) conditional dominant lethality and (ii) fluorescence.

The conditional lethality trait encoded by tTAV represses the normal development of the mosquito in the absence of the antibiotic tetracycline. Hence, when this LMOs mate with individuals of the opposite sex (either non-modified or LMOs) the resulting progeny that arise from this mating will be LMOs containing the tTAV dominant gene and expressing the conditional lethality trait, resulting in the death of such individuals in the absence of tetracycline.

The fluorescence trait is based on the expression in the OX513A(My1) strain of a red fluorescent protein encoded by the DsRed gene. Consequently OX513A(My1) LM mosquitoes have a fluorescent phenotype when excited by light of a suitable wavelength. This trait is used as a marker to distinguish OX513A(My1) individuals from their non-modified counterparts.

Aedes aegypti of the Rockefeller strain
Point of collection: Malaysia

Plasmid pLA513 and piggyBac "helper" plasmid phsp-pBac

For detailed information on the DNA sequences inserted into this LMO, please refer to the article by Phuc et al. (2007) available at the end of this record.

Information on OX513A(My1)

OX513A(My1) is a bisex RIDL strain, which means that both female and male insects die unless supplied with the supplement, which in the case of OX513A(My1) is the antibiotic tetracycline.

Released bisex RIDL insects and their progeny die within a few weeks so releases must be sustained to maintain the control.

Source: Oxitec (see developer field above).

Information on the Release of Insects carrying a Dominant Lethal (RIDL) technology

Release of Insects carrying a Dominant Lethal (RIDL) is a method using recombinant DNA technology to create genetically modified insects for biological control. The dominant lethal gene kills the insects but it can be repressed by an external additive, which allows the insects to be reared in manufacturing facilities. This external additive is commonly administered orally, and so can be an additive to the insect food. The insects can also be given genetic markers, such as fluorescence, that make monitoring the progress of eradication easier.

There are potentially several types of RIDL, but the more advanced forms have a female-specific dominant lethal gene. This avoids the need for a separate sex separation step, as the repressor can be withdrawn from the final stage of rearing, leaving only males.

These males are then released in large numbers into the affected region. The released males are not sterile, but any female offspring their mates produce will have the dominant lethal gene expressed, and so will die. The number of females in the wild population will therefore decline, causing the overall population to decline.

Using RIDL means that the males will not have to be sterilized by radiation before release (as done with the "Sterile Insect Technique" (SIT) using radiation), making the males healthier when they need to compete with the wild males for mates.

Source: Wikipedia (see link below).