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.This work was supported by National Institutes of Health Grant AI 16983-01.     

Genetics of three esterase loci in Anopheles stephensi liston

A survey of laboratory strains of Anopheles stephensi for nonspecific esterases by polyacrylamide gel electrophoresis revealed 10 zones of esterase activity. In 3 of the 10 zones, three electromorphs were observed. Genetic analysis revealed that these three zones are controlled by three loci, viz., Est-3, Est-4, and Est-5, and that the electromorphs are codominant alleles at each locus. The three esterase loci were found linked to each other and to an autosomal marker colorless-eye. The esterase loci have tentatively been placed in linkage group II. The probable gene sequence on chromosome 2 is either c-Est-3-Est-4-Est-5 or c-Est-4-Est-3-Est-5.     

A genetically controlled lactate dehydrogenase variant at the B locus in mink

Erythrocytes of 119 mink, and tissue extracts of three mink, were examined for electrophoretic patterns of lactate dehydrogenase (LDH). A variant was detected at the B locus. There are two alleles, LDH-B ^a and LDH-B ^b; three phenotypes, LDH-Ba, LDH-Bab, and LDH-Bb; and three genotypes, LDH-B ^a/LDH-B^a, LDH-B^a/LDH-B^b, and LDH-B ^b/LDH-B^b. The inheritance as observed in 24 families agrees with an autosomal, codominant, two-allele system at the LDH B locus.Supported by National Research Council Grant A-4442 and the Ontario Department of Agriculture and Food.     

Esterases in the mosquito Culex pipiens pipiens L.: Formal genetics and polymorphism of adult esterases

The genetics of two esterase loci active in autogenous adults of the mosquito Culex pipiens pipiens L. has been studied by means of starch gel electrophoresis. Three alleles at the Est-1 locus and eight at the Est-2 locus are described. Both loci have a null allele. Active alleles are codominant and there is no hybrid enzyme in heterozygotes. The Est-1 locus codes esterases preferentially hydrolyzing -naphthylacetate and the Est-2 locus esterases preferentially hydrolyzing -naphthylacetate. Strains homozygous for both loci were selected. Linkage studies of the two loci have shown that they are not sex linked but are linked to each other, the crossover frequency being 8.6%. The polymorphism of two laboratory and two natural populations is described for both loci. Phenotypic distributions are in good agreement with Hardy-Weinberg expectations.This work was conducted at the Université des Sciences et Techniques du Languedoc (Laboratoire de Génétique Expérimentale des Populations), Montpellier, France, in partial fulfillment of the requirements for the degree of Docteur de spécialité.     

Serum esterase genetics in rabbits. II. Genetic analysis of the prealbumin esterase system,including atropinesterase and cocainesterase polymorphism

The zymotypic variation of rabbit prealbumin esterases is controlled by three autosomal loci, each with two alleles: Est-1 ^S and Est-1 ^s, Est-2^F and Est-2 ^f′, Est-3^D and Est-3 ^d. Est-1^S gives rise to the three S zones possessing the cocainesterase activity, Est-2 ^F to the three F zones with atropinesterase activity. Presence of the latter allele is never manifested without the Est-1 ^S allele. Est-3 ^D codes for the D zone. This D esterase reacts with the currently used substrate α-naphthylacetate only in the presence of the F zones. Est-1 and Est-2 loci are closely linked (<0.5% recombination); Est-3 shows no coupling with Est-1 and Est-2. The Est-1 ^S and Est-3 ^D alleles have a complete dominant expression, whereas the Est-2 alleles are codominant. Gene frequencies of the Est-1 and Est-2 loci vary between the examined breeds. A Hardy-Weinberg equilibrium is found in two populations (Cpb:ALU and Cpb:VW). A significant surplus of heterozygotes is demonstrated in a third population (Cpb:CH).     

Polymorphism and chromosomal location of endogenous α-amylase inhibitor genes in common wheat

Summary Polymorphism of an endogenous -amylase inhibitor in wheat was studied using iso-electric focusing followed by monoclonal antibody — based immunoblotting. Ten isoforms of the inhibitor detected in common wheat and its wild counterparts were assigned to five homoeologous loci. Three -amylase inhibitor loci (Isa-1) were identified in common wheat and located on the long arms of chromosomes 2A, 2B and 2D. In a sample of 27 bread wheats, eight durum wheats, and 12 diploid wheat relatives, amphiploids and triticales, a high resolution isoelectric-focusing separation demonstrated two active and one null allele at the Isa-A1, two alleles at the Isa-B1, one allele at the Isa-D1, four alleles at the Isa-S1, and one allele at the Isa-G1 locus. The most frequent electrophoretic pattern of common wheat cultivars consisted of two isoforms, encoded respectively by the Isa-B1b, Isa-D1 a alleles and the Isa-Alnull allele. All the durum wheats had only one inhibitor form controlled by allele Isa-B1b, which was accompanied by the null allele at the Isa-A1 locus.Contribution No. 210 of the Food Science Department, University of Manitoba     

Genetic control of two esterases of rat plasma (Rattus norvegicus)

Three electrophoretic variants of plasma esterase in the albumin zone, presumably carboxylesterase, have been demonstrated in 250 rats representing a laboratory population of Wistar rats. Electrophoretic variants of the enzyme are believed to be controlled by two codominant alleles at the autosomal locus referred to as Es-2. The variant of carboxylesterase represented by a fast-migrating single band on starch gel electrophoresis is determined by the gene named Es-2 ^a, whereas the slow-migrating variant, represented by two bands, is under control of the allelic gene Es-2 ^b. Animals with Es-2 ^a/Es-2 ^b genotype have three bands of carboxylesterase in the albumin zone. Genetically determined polymorphism of plasma esterase, presumably carboxylesterase, in the prealbumin zone was shown in both laboratory and wild populations of rats. Breeding tests suggest that the gene referred to as Es-1 ^a, responsible for the presence of carboxylesterase in the prealbumin zone, is inherited dominantly, whereas animals homozygous for the allele Es-1 ^b locked this esterase fraction.     

The genetics of glutamic-pyruvic transaminase in mice: Inheritance,electrophoretic phenotypes,and postnatal changes

Glutamic-pyruvic transaminase (GPT, E.C. 2.6.1.2) from 18 inbred strains of mice was subjected to starch gel electrophoresis. Two electrophoretic phenotypes were observed: a fast-migrating pattern in 16 strains and a slower-migrating pattern in two strains. A comparison of electrophoretic patterns of F₁ and backcross progeny of two strains of mice showed that the inheritance of GPT is autosomal with two codominant alleles. The genetic locus for GPT is designated Gpt-1, and its two alleles are designated Gpt-1 ^a and Gpt-1 ^b to represent the fast-migrating (A) and slow-migrating (B) patterns. The GPT was expressed in 11 tissues with different amounts of enzyme activity. Developmental studies of GPT activity in liver showed that between 5 and 12 days after birth the mean activity was 10 units/g protein. Between 12 and 19 days, a dramatic rise in activity occurred and adult values of 300 units/g protein were reached by 26 days.This research was supported by The National Foundation (CRBS-258) and the National Institutes of Health (GM15253).Preliminary results were reported at the Annual Meeting of the American Society of Human Genetics, October 11–14, 1972, in Philadelphia.R. P. D. is an investigator of the Howard Hughes Medical Institute.     

Geographical patterns of genetic variability in introduced Australian populations of the marine toad,Bufo marinus: Sorbitol dehydrogenase,Sdh

The marine toad, Bufo marinus, was introduced to Australia from Hawaii in 1935. From 1935 to 1974, the toad population expanded exponentially to occupy 584,000 km², and now has a continuous distribution from Cape York to Tweed River on the eastern coast of the continent. Genetic analysis of the population indicates a difference in allele frequency at the sorbitol dehydrogenase locus. There are two alleles segregating at the locus (NAD-Sdh^a and NAD-Sdh^b). The NAD-Sdh^aa homozygote is common in the two southern populations, but uncommon in northern populations. The north-south difference has been established in less than 25 generations.     

Species relationship in the Pennisetum gene pool: enzyme polymorphism

Summary Variation in leaf esterases (EST), 6-phosphogluconate dehydrogenase (PGD), shikimate dehydrogenase (SKDH), leucine aminopeptidase (AMP), phosphoglucomutase (PGM) and malate dehydrogenase (MDH) is reported in the Pennisetum gene pool. In the primary gene pool, polymorphism for EST, AMP, SKDH was very high, as compared to the near-monomorphic isozymes of PGD. Two loci controlling leaf esterases Est-1 and Est-2, were identified in the primary gene pool. Differences in allelic frequency distribution of the polymorphic Est-1 locus occur between the cultivated and wild pearl millet. The prevalent alleles of Est-1 are absent in P. purpureum Schumach (secondary gene pool). A monomorphic band of the -esterase-specific Est-2 locus was identified in most of the secondary gene pool accessions, P. squamulatum Fresen and an accession of P. pedicellatum. SKDH and EST revealed differences between most of the tertiary gene pool species. By contrast, a PGD zymogram was prevalent in several species of different sectional taxa. Gene duplication for PGD isozymes occurs in the diploid species, P. ramosum, of the tertiary gene pool. Heterodimers of PGD and EST were observed in the hybrid between pearl millet and P. squamulatum, whereas a monomeric structure characterized SKDH and AMP.     

Est-2 and Est-3 polymorphisms in Culex pipiens L. from southern France in relation to organophosphate resistance

Est-2 and Est-3 linkage disequilibrium was investigated in 43 natural populations. An association between Est-2 ^0.64 and Est-3 ^A alleles (or its reverse, Est-3 ^Null and alleles other than Est-2 ^0.64) was not observed in 19 (1.2%) of the 1599 mosquitoes analyzed, whereas it should have been found in nearly 400 (25%) individuals if the two loci were in equilibrium. This observation is discussed in relation to organophosphate resistance and genetic distance of the two genes.     

Genetic control of lactate dehydrogenase isozymes in Paramecium caudatum

The LDH isozymes were surveyed in bacterized cultures of syngens 1, 3, 12, and 13 of Paramecium caudatum by polyacrylamide gel electrophoresis. All the examined stocks of different syngens except one stock in syngen 3 had a single common LDH isozyme, and intra- and intersyngenic variation was not observed except for the one stock in syngen 3. Breeding data using the exceptional stock indicated that the LDH isozymes of P. caudatum are controlled by two codominant alleles at a single locus whose products aggregate randomly, forming a dimer.     

Serum esterase genetics in rabbits. IV. The prealbumin and β-globulin systems

Discontinuous starch gel electrophoresis revealed a fourth allele of rabbit prealbumin serum esterase at locus Est-2. This allele is designated Est-2 ^f and appears to be silent. In addition to the prealbumin serum esterases, another serum esterase system was studied in rabbits. This system is localized in the β-globulin region. Genetic analysis indicated that one locus with two codominant alleles controls the variation in this region. Linkage of this system with Est-1 and Est-2 of the prealbumin serum esterases was demonstrated. Comparison of the arrangement of these esterase loci on linkage group VI with the esterase loci on chromosome 8 of the mouse gives additional support for the theory of evolutionary conservation of chromosomal segments coding for mammalian esterases.     

Polymorphism of the sixth component of complement (C6) in the dog

Isoelectric focusing was used to identify five alleles at the locus determining the production of the sixth component of complement (C6) in the dog. Four of these alleles,C6 ¹, C6², C6⁴,andC6 ⁵,were studied in family pedigrees and shown to be inherited in a codominant autosomal fashion. All alleles except forC6 ⁴occurred commonly in the multiple breeds tested. This investigation was supported by Grant HL 17265 awarded by the National Institute of Heart, Lung, and Blood Diseases, DHEW, and by Grants CA 18105 and CA 31787 awarded by the National Cancer Institute.     

Inheritance of some marker genes in Setaria italica (L.) P. Beauv.

Summary A study on a series of genetic markers was run on five hybrids of foxtail millet, Setaria italica, and on one interspecific hybrid S. viridisxS. italica (S. viridis is the wild relative of S. italica). Seven enzymatic systems were investigated using starch gel electrophoresis (esterase, alcohol dehydrogenase, glutamate oxaloacetate transaminase, acid phosphatase, malate dehydrogenase, 6-phosphogluconate dehydrogenase, cathodic peroxidase). This genetic analysis of the 6 F2 has allowed us to define 12 polymorphic loci: Est-1, -2 and -3, Adh-1, Got-1 and -2, Acph-1, Mdh-1 and -2, Pgd-1 and -2, and Pox-1. All of them behaved like dimers, except Est-1 and Est-2 which showed monomeric structures. Two other markers were examined: waxy endosperm, which appeared to be controlled by one locus, and anthocyanic pigmentation of the collar, for which at least two loci are responsible. Studies of linkage carried out on three F2 showed two linkage groups: Mdh-1, Pox-1, Wx, Est-3, and a locus for collar colour, and Est-2, and one or two other loci of colouring.     

Glutamate oxalate transaminase (GOT) genetics in Mus musculus: Linkage,polymorphism, and phenotypes of the Got-2 and Got-1 loci

A comparison of electrophoretic patterns of F₁ and backcross progeny of two inbred strains of mice has revealed a new autosomal variant of the mitochondrial form of GOT. The loci controlling the production of the soluble and mitochondrial forms of GOT have been designated Got-1 and Got-2, respectively. The two alleles of the Got-2 locus have been designated Got-2 ^a and Got-2 ^b, which represent the slow- and fast-migrating electrophoretic forms. Twenty-seven inbred strains of mice have been classified for Got-2 ^a and Got-2 ^b. It has been demonstrated that the polymorphism of Got-2 is widely distributed in feral mice. Got-2 was shown to be linked to Es-1, and evidence is also presented for linkage between Got-2 and Es-2, Es-5, and oligosyndactyly (Os). The absence of linkage of Got-2 to seven other loci has also been demonstrated. GOT was expressed in vitro in cell lines derived from human and mouse tissues.     

Genetic control of leucine aminopeptidase and esterase isozymes in the interspecific cross Cucurbita ecuadorensis x C. maxima

Starch gel electrophoretic analyses of crude seed extracts of Cucurbita ecuadorensis, C. maxima, their F₁ and F₂, and three of the four possible interspecific backcrosses reveal that the genus is polymorphic for alpha-naphthyl acetate esterases (Est) and leucine aminopeptidase (LAP). The two electrophoretic forms of both Est and LAP are controlled by codominant alleles. The two loci do not exhibit linkage. Neither the LAP nor the Est phenotypes exhibit a significant deviation from the expected 1:1 ratio in interspecific backcrosses when the donor parent alleles are transmitted through female gametes, but there is a significant deviation for Est when transmission is through male gametes. Differential gametic selection involving the Est-1 locus suggests structural differences between the genomes of the parental species for the chromosomal region in which this locus occurs. No structural differences are indicated between the parental genomes for the chromosome region bearing the Lap-1 locus.     

Genetic study of pancreatic proteinase and α-amylase in mice (Mus musculus)

Genetic variants were found at two loci for pancreatic proteinase in mice. The Prt-1 locus contains a pair of allelic genes, Prt-1 ^a and Prt-1 ^b , ad the Prt-2 locus contains two codominant allelic genes, Prt-2 ^a and Prt-2 ^b .Expression of the two genetic variants of proteinase allowed mice strains used in this study to be classified into three phenotypic classes. Prt-1 ^b andPrt-2 ^a were found in most of the Japanese inbred strains, Prt-1 ^b andPrt-2 ^a were found in most of the inbred strains imported from the United States, and, furthermore, Prt-1 ^b and Prt-2 ^b were present in Japanese feral-origin mice strains. Prt-1, Prt-2, and Amy-2 loci did not belong to the same linkage group.     

Genetics of a tissue esterase polymorphism (Est-6) in the rabbit (Oryctolagus cuniculus)

Genetic analysis of a polymorphic tissue esterase revealed a new locus (Est-6) with two alleles (Est-6 ^a andEst-6 ^b) on linkage group VI of the rabbit.Est-6 is closely linked to theEst-1,2,4 cluster. Esterase ofEst-6 is found in many organs, particularly in liver and small intestine, but not in erythrocytes and serum.Est-6 esterase hydrolyzes -naphthyl acetate and butyrate, naphthol AS-D acetate, indoxyl acetate, and butyrate as well as 5-bromoindoxyl acetate,N-acetyl-l-alanine--naphthyl ester but not 4-methylumbelliferyl acetate and fluorescein diacetate. The enzyme is inhibited by bis-p-nitrophenyl phosphate and eserine but not byp-chloromercuribenzoate. It was classified as a carboxylesterase (EC 3.1.1.1). Based on chromosomal localization, tissue distribution, substrate specificity, inhibitor sensitivity, and range ofpI's, rabbitEst-6 is assumed to be homologous with mouseEs-7.The contribution of Dr. O. von Deimling (No. 59) was supported by the Deutsche Forschungsgemeinschaft (De 315/2-2).     

Genetic control and linkage relations of additional isozyme markers in chick-pea

Summary Allozyme polymorphisms of nine enzymes — aspartate aminotransferase (AAT), diaphorase (DIA), esterase (EST), formate dehydrogenase (FDH), -galactosidase (GAL), -glucosidase (GLU), malate dehydrogenase (MDH), malic enzyme (ME), and peroxidase (PRX) — were described in chick-pea (Cicer L.). Thirteen isozyme loci, Aat-c, Dia-4, Est-2, Est-4, Est-10, Fdh, Gal-2, Gal-3, Gal-4, Glu-3, Mdh-2, Me-2, and Prx-2, were genetically defined. Alleles of each of these isozyme loci expressed codominantly in heterozygotes and exhibited a codominant, single-locus segregation ratio in F₂. The loci Est-2, Mdh-2, and Me-1 were expressed only in flower. Linkage relations were determined for these 13 and several previously defined isozyme loci. The following new genetic linkages were identified: Pgm-p (locus for plastid phosphoglucomutase) — Est-10; Ald-p1 (one of the duplicate loci for plastid aldolase) — Glu-3 — Gal-2 — Est-2,3; Gal-3 — Aco-m (locus for mitochondrial aconitase) — Prx-2,3; Gpi-c (locus for cytosolic glucosephosphate isomerase) — Fdh; and Est-4 — Me-1. This study provides further confirmation on the existence of several conserved linkage groups among Cicer, Pisum, and Lens.