Insect Molecular Biology (1997) 6(3), 291±299 SHORT NOTE The white gene from the yellow fever mosquito, Aedes aegypti C. J. Coates, 1 T. L. Schaub, 1 N. J. Besansky, 2 F. H. Collins 2 and A. A. James 1 1 Department of Molecular Biology and Biochemistry, University of California, Irvine, California, and 2 Division of Parasitic Diseases, Centers for Disease Control, Chamblee, Georgia, USA Abstract We report the cloning and primary characterization of both cDNA and genomic fragments from the white gene of the yellow fever mosquito, Aedes aegypti. Compar- isons of the conceptual translation product with white genes from four other species within the order Diptera show that the Ae. aegypti gene is most similar to the white gene of the mosquito vector of human malaria, Anopheles gambiae (86% identity and 92% similarity). The analysis of the primary sequence of genomic DNA at the 5'-end of the coding region revealed the pre- sence of an intron that is also present in An. gambiae, but not in the vinegar ¯y, Drosophila melanogaster. The isolated clones of the Ae. aegypti white gene will enable the construction of a marker gene for use in the development of a germline transformation system for this species. Keywords: Aedes aegypti, marker gene, transforma- tion, white gene. Introduction The yellow fever mosquito, Aedes aegypti, is an impor- tant vector of several human disease agents, including pathogens that cause lymphatic ®lariasis, yellow fever, dengue fever and chikungunya fever (Nasci & Miller, 1996). The most commonly used forms of Aedes popu- lation control include source reduction through envir- onmental sanitation (Mitchell, 1996) and the use of insecticides targeted at larval or adult stages. Both of these strategies have inherent problems, including the diculty in removing urban container-breeding sites and the development of resistance to the insecticides used for control (Ferrari, 1996). Genetic control of Ae. aegypti populations has been attempted using the Sterile-Insect Technique (SIT) and the use of strains carrying chromosomal translocations (reviewed in Rai, 1996). A major problem with the strains used for these trials was a reduced ®tness of the released individuals. Recently it has been proposed that disease control can be achieved by producing and releasing transgenic mosquitoes (Meredith & James, 1990; Collins & James, 1996). A major hindrance in the development and improvement of genetic control release strains is the lack of a stable germline trans- formation system for Ae. aegypti. The availability of this tool would also enable a greater understanding of the basic biology of the mosquito and, more speci®cally, the mechanisms of virus and parasite transmission. Until recently the only insect species in which a germline transformation system existed was Droso- phila melanogaster and its close relatives (Spradling & Rubin, 1982; Brennan et al., 1984; Scavarda & Hartl, 1984). Successful genetic transformation has also now been reported in the Mediterranean fruit ¯y, Ceratitis capitata (Loukeris et al., 1995). Both of these systems rely on the use of a transposable element to integrate foreign DNA into germline chromosomes, thus allow- ing heritable traits to be introduced. The Hermes transposable element from the house¯y, Musca domestica, has been shown to be capable of interplas- mid transposition within the embryonic soma of Ae. aegypti (Sarkar et al., 1997). Hermes therefore satis®es one of the requirements for the development of a transformation system for Ae. aegypti. It should be a suitable vector for the integration of foreign DNA into Ae. aegypti germline chromosomes. Another important component of a successful trans- formation system is the use of a marker gene to allow the rapid detection of transgenic individuals from a pool of non-transformed siblings. The most successful and widely used marker gene in Drosophila has been the white gene (Gehring et al., 1984; Hazelrigg et al., Received 18 February 1997; accepted 17 April 1997. Correspondence: Dr A. A. James, Department of Molecular Biology and Biochemistry, University of California, 3205 Bio Sci II, Irvine, CA 92697±3900, USA. AID=IMB183 ARTTY=OA # 1997 Blackwell Science Ltd 291