Genetic Applications to Improve the SIT for Tsetse Control/Eradication Including Genetic Sexing

Objective:

To develop tools for the genetic analysis of tsetse field populations. This includes genetic, molecular and cytological approaches.

Activities:

A better understanding of the phylogenetic relationships between different tsetse species, subspecies and strains, and of heritable traits that can be subjected to selection pressure is of particular importance for appropriate action on the tsetse / trypanosomosis problem. Data on genetic variation within a target population and information on the gene flow among neighboring tsetse fly populations will have implications for planning and implementation of area-wide supression / eradication campaigns. The possible development of resistance (physiological or behavioral), based on the selection of particular genotypes, will interact with and influence the type of control measure chosen and its mode of application.

Isozyme analysis for field populations of tsetse is not well developed due mainly to difficulties in obtaining field material in the right condition. Nevertheless, because of the high sensitivity of this analysis work is being carried out in this area. As DNA analysis is not affected by these problems in the same way, mtDNA, RAPD and microsatellite analyses are being pursued. All these approaches are PCR based. Polytene chromosome analysis has also been started and initial chromosome banding patterns have been established. The symbionts that tsetse carry are also being investigated as these are involved in trypanosome development in the fly and those present in the reproductive organs could be used to develop markers for released strains. At present all attention is focussed on Glossina pallidipes because of its relevance to a proposed SIT programme in Ethiopia.

Emphasis was also laid on the development of an automated sexing method for immature fly stages (genetic sexing), and on other genetic or related techniques that foster an efficient large-scale application of the SIT. This also includes research directed at a trans-taxon use of laboratory-reared sterile flies for tsetse and trypanosomosis supresion or eradication activities.

Participants:

Two Contract Holders from Greece and Kenya, and five Agreement Holders from Belgium, Canada, Italy, and USA (2).

Reports: