Takeo Tadano

Linkage studies on an esterase locus in the mosquito Aedes togoi

An electrophoretic survey of esterases in 7 wild-type and 10 mutant strains of the mosquito Aedes (Finlaya) togoi was undertaken using thin-layer agar gels. Three esterases (designated the Est-1, Est-2, and Est-3 loci in decreasing order of electrophoretic mobility) could be detected from fourth-instar larvae, pupae, and 2- to 5-day-old adults. Homogenates of the larvae gave the most intensely stained bands in the gels, especially for Est-3. The three esterases were designated carboxylesterases based on their response to the two esterase inhibitors, eserine and paraoxon (diethyl-p-nitrophenyl phosphate). The Est-3 locus was found to have five alleles including at least one null. The linkage results of six backcrosses suggest that Est-3 is located only 5–8 map units from the sex allele (m) and the gene arrangement is Est-3-m-s (straw-colored larva) in linkage group I.

Genetics of octanol and α-glycerophosphate dehydrogenases in the mosquito Aedes (Finlaya) togoi

Genetic studies were performed on octanol dehydrogenase (EC 1.1.1.73) and α-glycerophosphate dehydrogenase (EC 1.1.1.8) in the mosquito Aedes (Finlaya) togoi by agar gel electrophoresis. The electrophoretic survey revealed two octanol dehydrogenase loci (Odh-1, Odh-2) and one α-glycerophosphate dehydrogenase locus (α-Gpdh) in this species. Five alleles were observed at the Odh-2 locus in seven laboratory strains, whereas the α-Gpdh locus was completely monomorphic in six of seven strains examined and the second allele at this locus was detected in only one strain at a frequency of 0.14. Both loci code for dimeric enzymes. Linkage studies on Odh-2 and α-Gpdh suggested that the gene arrangement and recombination units were Odh-2—(25.8)—M (sex locus)—(30.5)—s (strawcolored larva) and M—(25.6)—α-Gpdh—(15.4)—s. These results, together with linkage data previously reported, give the following gene linkage on the sex chromosome: Odh-2—Est-3 (carboxylesterase)—Acph (acid phosphatase)—M—α-Gpdh—s—Est-2 (carboxylesterase). The total map length of this arrangement is approximately 75 map units.

Genetic linkage relationships between two enzyme loci, Est-2 and acph, in the mosquito Aedes (Finlaya) togoi

An esterase locus (Est-2), coding for carboxylesterase, and an acid phosphatase locus (Acph) were genetically studied by agar gel electrophoresis in the mosquito Aedes (Finlaya) togoi. The Est-2 and Acph variants occur as a monomer and a dimer, respectively. Both enzyme loci are linked to the sex locus (M) and s (straw-colored larva); the gene arrangement and recombination distances were Est-2—12.6%—s—31.7%—M—2.9%—Acph—3.2%—Est-3. The Est-3 locus was previously shown to code for carboxylesterase.

The inheritance of a mutant yellow larva in the mosquito Aedes togoi

In the mosquito Aedes (Finlaya) togoi (Theobald), which usually breeds in seawater in tidal pools and is a natural or experimental vector of various species of filariae, the mode of inheritance of a new mutant yellow larva (y) was investigated; the y allele is recessive and inherited independently of sex and its linked alleles, and independently of ruby eye (ru) and pigmented pupae (p), both of which are not sex-linked; therefore y is presumed to be on the third linkage group in this species. The allele y is completely penetrant with little variation in its expressivity, but its phenotype could not be reliably distinguished from that of sex-linked allele straw-coloured larva (s).

Genetic studies on hexokinase in the mosquitoAedes togoi

Hexokinases (EC 2.7.1.1) were genetically analyzed in the mosquitoAedes togoi by agar gel electrophoresis. Enzyme activity was observed anodally in one major banding region (HK-1) on the gel and in another faintly stained region (HK-2). A total of six bands was detected in the HK-1 region. All six bands could be detected in three body parts, head, thorax, and abdomen, of adults with different banding intensities. The third and fourth bands, numbered from the more anodal side, showed the broadest substrate specificity and the greatest enzyme activity throughout development. Genetic analysis of the six HK-1 bands was undertaken on the hypothesis of a single gene locus (or three extremely tightly linked loci). The analysis gave the following gene order:HK-1—4.2±1.8 (recombination units±SE)—To-2—Odh-2—29.5±2.5—sex (M/m)—s. A comparison is made of gene loci for hexokinases among the mosquito speciesCulex pipiens, Aedes aegypti, and this species, along with a comment on linkage relationships betweenHk andOdh (octanol dehydrogenase) loci in threeAedes species.

Linkage studies on ?-glycerophosphate and isocitrate dehydrogenases in Aedes albopictus (diptera: Culicidae)

Linkage studies were carried out on α-glycerophosphate dehydrogenase (α-GPDH) and isocitrate dehydrogenase (IDH) in the mosquito Aedes (Stegomyia) albopictus. Only one locus coding for α-GPDH was revealed on agar gels by applying adult homogenates. Two loci for IDH were observed using either fourth-instar larvae, pupae, or adults. This study was restricted to the more anodal Idh-2 of the two loci, and α-Gpdh. Both α-Gpdh and Idh-2 encode dimeric enzymes. Thirteen backcrosses indicated that the α-Gpdh and Idh-2 loci are arranged in linkage group 2 in the following order: p (pigmented pupa)—(ca. 2 map units)—Wb (white-body)—(7.5–17.8)—Idh-2—(13.1)—α-Gpdh. Females exhibited more recombination than males.

Genetics of white eye in the mosquito Aedes togoi

The white-eye mutant (w), isolated in the mosquito Aedes (Finlaya) togoi, a vector of various species of filariae, is recessive and fully penetrant; this spontaneous mutant can be distinguished from other eye-colour mutants throughout its life cycle. Linkage studies by two-, three-, and four- point backcrosses revealed that the w allele was linked to the p (pigmented pupa) allele in linkage group 2 and the recombination units varied from 31·2±3·0 to 47·4±1·2, and that p was linked to ca (cut antenna), as reported earlier, with recombination units of 34·7±2·1 to 35·9±2·0. This and previous studies suggested the gene sequence as ca—(eight units)—ru (ruby eye)—(30 units)—p—(over 40 units)—w; the total length of linkage group 2 thus far measured is roughly 80 map units. The w allele was epistatic to ru.

Disturbed venation, a new sex-linked mutant, in the mosquito Aedes togoi.

Genetic linkage of a new sex-linked mutant, disturbed venation (dv), in Aedes (Finlaya) togoi has been studied by utilizing representative markers, s (straw-coloured larva), ru (ruby eye), and y (yellow larva), of the three linkage groups. The dv allele is recessive, disturbs drastically venation of the wing veins, cu1, m1+2, m3+4, r2, r3, and r4+5, and also affects shape of the wings along with loss of many fringe scales. The wings become shortened, especially in females, and somewhat narrowed in males. Much variation occurs in the expression of dv with its fairly good penetrance, although an increased mortality of the dv homozygotes may occur at pupal stage or during emergence. This allele was located at 5 to 6 recombination units from s and 28.56 units from sex locus (M) in the gene order of s-dv-M.

Genetics of a new mutant, curved wing, of the mosquito Aedes togoi.

A new recessive mutant curved wing (c) in the mosquito Aedes (Finlaya) togoi (Theobald), a vector of various species of filariae in the Far East, has been shown to be linked to yellow larva (y), with a recombination value of 13.26 +/- 1.41 to 20.53 +/- 1.41%. These linked alleles are inherited independently of either sex (M), straw-coloured larva (s), ruby eye (ru), or pigmented pupa (p). Evidence has now been produced that sex (M)-s, ru-p, and y-c mark the three linkage groups in this species (2n = 6), and these markers, respectively, have been placed provisionally in linkage groups 1, 2, and 3.