Genetic Traits of the Mosquito Anopheles gambiae: Red Stripe, frizzled, and homochromy1

The expression, inheritance, and linkage relationships of three genetic traits were studied in the malaria vector Anopheles gambiae. Red stripe (Rs) is a common phenotypic polymorphism in numerous A. gambiae populations, whereas frizzled ( f ) and homochromy1 (hom1) were isolated from 60 Co-irradiated mosquitoes. Red stripe appears as a diffuse stripe of pigment on the dorsum of larvae and pupae and is variable in expressivity and penetrance. Our data demonstrate that Red stripe results from a heterozygous collarless genotype (i.e., cþ c, chromosome 2) and is essentially sex-limited to females. frizzled is a sexlinked recessive semi-lethal identified by deformed lateral larval setae; its lethality manifests as low rates of adult emergence and brief adult survival. frizzled is located on the X chromosome between pink eye and Mosaic, 3 cM from Mosaic and approximately 12 cM from pink eye. Finally, the mutation homochromy1 (hom1) is on chromosome 2 and causes a recessive phenotype that prevents normal darkening of larvae when reared in a black container. Unlike mutants with this characteristic described thus far, the eye color of hom1 mutants is normal. We determined that hom1 is located between Dieldrin resistance and collarless, approximately 3 cM from the latter. We discuss the possibility of differences in male and female recombination values and the range of values that have been observed in testcrosses for chromosome 2 markers.