[Gene mapping on the salivary gland chromosomes of the mosquito Culex pipiens L].

Crossing experiments were done with several mutations and aberrant lines of the mosquito Culex pipiens L. Gene loci and chromosomal structure could be correlated by comparing crossover rates of mutations with breakage points of chromosomal aberrations in the larval salivary gland chromosomes. This confirms linkage groups and their correlated chromosomes.Before comparing crossover rates in one chromosome in different experiments, the problem of different crossover rates between two distinct factors should be solved. The reason for these different rates is not sex, age or small chromosomal aberrations in the heterozygous individuals. It could be interstrain behaviour, characteristic for each strain. This was shown by comparing crossover rates of an allelomorph mutation in two different laboratory strains. Therefore, only results within one pure strain or between two strains with known correlation can be compared. In the small chromosome I, the correlation of the sex-determining allelomorphs M and m with the heteromorphic band 10 C 3 in arm I L was confirmed. This was done by crossover analysis of breakpoints in sex-linked aberrations. The locus of the eye colour mutation w is situated near this band. The eye colour mutation r is located in the segment 3 B/C in arm I R.In chromosome II, two gene loci are narrowed down: the larval colour mutation d is situated on the distal end of arm II L, the eye colour mutation ru in the central part of arm II R. In chromosome III, the male-limited mutation kps is located in arm III L.Hitherto only the sex-factor could be correlated which a distinct structure, i.e. the heteromorphic band 10 C 3 in arm I L. The results of the described experiments made it possible for the first time to establish a cytological gene map of Culex pipiens.