S. S. Dhaliwal

Genetics of glucose phosphate isomerase and phosphoglucomutase in Aedes albopictus (diptera: culicidae).

SummaryGlucose phosphate isomerase (E.C. 5.3.1.9) and phosphoglucomutase (E.C. 2.7.5.1) were found to be polymorphic in a laboratory colony of Aedes albopictus. The glucose phosphate isomerase locus is represented by two alleles resulting in three genotypes, while the phosphoglucomutase locus is represented by at least five alleles giving rise to a total of 15 genotypes. The inheritance of these two enzymes is of the Mendelian type with codominant alleles. Present data indicate that these genes are not linked.Of 105 mosquitoes analysed for these two gene-enzyme systems, the frequencies for glucose phosphate isomerase alleles are GpiS=0.68 and GpiF=0.32, while the frequencies for phosphoglucomutase alleles are PgmA=0.16, PgmB=0.11, PgmC=0.19, PgmD=0.30 and PgmF= 0.24. The frequencies of the three glucose phosphate isomerase genotypes are in accord with Hardy-Weinberg expectations (X12=2.74). Similarly, the frequencies of the 15 phosphoglucomutase genotypes probably do not differ significantly from Hardy-Weinberg expectations (X102= 18.45).

Somatic chromosomes of the flat-headed bats (Tylonycteris spp)

Zwei sympatrische, nahverwandte Fledermausarten,Tylonycteris pachypus (Temminck) undT. robustula Thomas, besitzen 46 beziehungsweise 32 Chromosomen, was offenbar den Robertsonschen Translokationen zuzuschreiben ist.

Biochemical genetic relationship in three taxa of the malaria mosquito Anopheles balabacensis complex

Three taxa of the malaria mosquito Anopheles balabacensis complex representing three geographical regions (Thailand, Peninsular Malaysia and Sabah) in Southeast Asia, were analysed for genetic variation at 15 gene-enzyme systems. The Sabah taxon was monomorphic for all the 15 gene-enzyme systems. Only two gene-enzyme systems (esterase and glucose phosphate isomerase) were variable in the Thailand and Peninsular Malaysia taxa. The average heterozygosity or gene diversity was 0.007 for the Thailand taxon and 0.028 for the Peninsular Malaysia (Perlis) taxon. There were no unique gene-enzyme markers in the three taxa studied. The average values of genetic identities (0.933-0.997) and genetic distances (0.003-0.069) indicate that these three taxa are of subspecific status.

Isocitrate dehydrogenase gene duplication and fixed heterophenotype in the cultivated soybeanGlycine max

Isocitrate dehydrogenase (E.C. 1.1.1.42) gene duplication was demonstrated in the self-pollinated soybean (Glycine max) by means of starch-gel electrophoresis. This finding explains the heterogeneity and/or fixed heterophenotype observed in some soybean cultivars.

Glucose phosphate isomerase and 6-phosphogluconate dehydrogenase polymorphism in Malaysian leaf monkeys

Glucose phosphate isomerase and 6-phosphogluconate dehydrogenase were found to be polymorphic in Malaysian leaf monkeys. Two glucose phosphate isomerase electrophoretic phenotypes were presumed to be homozygous. Three 6-phosphogluconate alleles and four electrophoretic phenotypes were present. The allele frequencies inPresbytis obscura werePgdA=0.64,PgdB=0.27 andPgdC=0.09. The frequencies of the 6-PGD phenotypes inP. obscura were not in accord with Hardy-Weinberg expectations. All the biochemical markers examined show identical electrophoretic patterns in the Malaysian leaf monkeys.

Multiple phosphoglucomutase alleles in two species of Mansonia mosquito.

Multiple phosphoglucomutase (E.C.2.7.5.1) alleles are found in the mosquitoesMansonia crassipes andM. uniformis. The present study reveals 4Pgm alleles, of whichPgm B andPgm C are common to both species whilePgm A is present only inM. crassipes andPgm D only inM. uniformis. The frequencies in both species accord well with Hardy-Weinberg expectations. The most frequent allele is that controlling a phenotype with an intermediate electrophoretic mobility, viz.Pgm B inM. crassipes andPgm C inM. uniformis.

A female norway rat, Rattus norvegicus, with x0 sex chromosome constitution

Man and the great majority of mammals have the common XX/XY sex chromosome mechanism. However, in addition to species with complex sexchromosome systems, individuals with deviating sex chromosome constitutions have been reported in man and in at least 16 mammalian species with the normal XX/XY mechanism [1]. The commonest types of deviation are XXY, XYY, and XX in individuals with male phenotype, and X0, XXX, and XY in individuals with female phenotype. Of these, the X0 condition appears to be the most common, having been reported in man and 11 species of mammals [1]. In man, the X0 condition leads to Turner syndrome [2]. On the other hand, X0 female mice are fertile [3, 4] but have a considerably shorter reproductive lifespan compared with XX females [5]. In general, large mammals with an X0 constitution are infertile, while small mammals with such a condition are fertile. Although the Norway rat (Rattus norvegicus) has been extensively studied cytologically, there appear to be no reports on the occurrence of X0 female individuals [1]. Indeed, until recently R. norvegicus has been considered an example of karyotypic stability. We report here the finding of a wild female Norway rat with an X0 sex chromosome constitution from Peninsular Malaysia. In August 1986, 8 male and 18 female wild R. norvegicus trapped from Seberang Prai in northwestern Peninsular Malaysia were karyotyped. Chromosome preparations were made from bone marrow by the conventional airdrying technique. All the male rats had a diploid number of 42 with an XY sex chromosome constitution. Seventeen of the female rats studied had a diploid number of 42 with an XX sex chromosome constitution. In the remaining female rat counts of 41 chromosomes were recorded in all the metaphases. Karyotype analysis indicated the presence of a single X chromosome (Fig. 1). The G-banded karyotype shows beyond doubt that this female rat has an X0 sex chromosome constitution. The present finding raises the number of rodent species with sporadic X0 individuals to five; the earlier reported species being Akodon azarae [6], Bandicota bengalensis [7], Mus musculus [3], and Rattus rattus [8 10]. As in the case of Rattus rattus [8], since bone marrow was the only tissue studied in the present female Norway rat, the possibility has to be borne in mind that the loss of the X chromosome might have been confined to bone marrow and perhaps other somatic tissues.

Multiple alleles and low variability of glycerol-3-phosphate dehydrogenase in Aedes albopictus (Diptera: Culicidae) from Peninsular Malaysia

1. A total of 8 samples from three natural populations and a laboratory strain of Aedes albopictus were analysed for glycerol-3-phosphate dehydrogenase phenotypes by means of horizontal starch-gel electrophoresis. 2. The electrophoretic phenotypes were governed by three codominant Gpd alleles. 3. There was low variability, with the heterozygosity in the variable samples ranging from 0.02 to 0.12. 4. The commonest allele in all the population samples was GpdB which encoded an electrophoretic band with intermediate mobility. 5. There was no temporal or spatial variation.

Multiple glucose phosphate isomerase alleles in Aedes albopictus (Diptera:Culicidae) from peninsular Malaysia

1. Three natural populations and a laboratory strain of Aedes albopictus were analysed for glucose phosphate isomerase by means of horizontal starch-gel electrophoresis. 2. The electrophoretic phenotypes were governed by five codominant Gpi alleles. 3. The commonest allele in all the four population samples was GpiC which encoded an electrophoretic band with intermediate mobility. 4. The distributions of GPI phenotypes were in accordance with Hardy-Weinberg expectations. 5. The four population samples could be differentiated by the presence of a unique Gpi allele or the absence of a particular Gpi allele.

Multiple phosphoglucomutase alleles inToxorhynchites splendens (Diptera: Culcidae)

Multiple phosphoglucomutase (E.C. 2.7.5.1) alleles are found in the mosquitoToxorhynchites splendens. The sample studied reveals 3Pgm alleles whose frequencies are in good accord with Hardy-Weinberg expectations. The most frequent allele is that controlling a phenotype with an intermediate electrophoretic mobility. EachPgm allele determines a two-band electrophoretic pattern.