Engineered genetic sterility of pest insects

Thesis

In the light of increasing pesticides resistance in agricultural pests and in insect vectors of human diseases, leading to the rise in occurrence of mosquito-borne diseases, new, efficient and environmentally friendly methods of pest control are needed.

Sterile Insect Technique (SIT), relying on mass releases of radiation sterilised males to reduce reproductive potential of target pest populations, although not new, offers an alternative to the use of pesticides and is an environmentally non-polluting method of insect control. Many insect species, however, are not very amenable to classical SIT, due to detrimental side-effects of radiation treatment.

We propose a new method, a genetically engineered modification of classical SIT, replacing radiation with genetically induced sterility. Based on conditional expression of male-germline targeted nucleases which introduce double strand breaks into the male germline DNA to render males sterile, this method emulates SIT mechanism, at the same time eliminating radiation and associated detrimental side-effects.

Different variants of such a system were investigated in this project, eventually leading to the creation of functional conditional male-sterility systems in two model organisms – the Yellow fever mosquito, Aedes aegypti and the Mediterranean fruit fly, Ceratitis capitata. Both systems utilise chimeric nuclease composed of protamine and FokI cleavage domain fusion. The sperm-specificity and the conditionality of the sterile phenotype have been achieved through the use of tetracycline repressible expression system driven by the β2-tubulin promoter in Ceratitis capitata and by the Topi promoter in Aedes aegypti.

Authors: Bilski, MM

• Publication date: 2012
• DOI: 10.5287/ora-54gdjbq70
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Keywords: sterile insect technique; transgenic insects; genetic pest control; sterile male; FokI nuclease; RIDL
• Subjects: Transgenics; Zoological sciences; Genetics (life sciences)