Models of stable underdominance have shown potential in driving the introduction of refractory genes into pest populations that are responsible for the spread of infective diseases such as
malaria and
dengue fever. A refractory gene alone would not have higher fitness than the native genes, but engineered underdominance may prove effective as a mechanism to spread such a gene. In this model, two genetics constructs are introduced into two non-
homologous chromosomes. Each construct is lethal when expressed individually but can be suppressed by the other construct. In this way, individuals with only one of the two constructed genes (heterozygotes) are selected against, but homozygotes with both or neither construct are genetically healthy. Analysis of this model using simple population genetics shows that successful spread of refractory genes using this engineered underdominance is possible with relatively small release of the constructed genotype into the population. The genetic construct in this system employs a dsRNAi knockdown of a
C-reactive protein, RpL14, as well as a rescue element (a complete copy of the
wild type RpL14 gene). Individuals that are heterozygous for this construct experience lowered fitness due to limited restoration of the RpL14 gene, which results in reduced female fertility and delayed development, along with various other mutations that ultimately lower fitness by 70-80%. This system of underdominance allowed manipulation of the population and ultimate fixation of the constructed genotype and has potential applications in a number of settings, including agriculture and the reduction of various pest-carried diseases. == See also ==