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.     

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.     

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.     

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.     

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.     

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.     

Studies of a homologous gene-enzyme system,Esterase C,in Drosophila melanogaster and Drosophila simulans

Electrophoretic variants of nonspecific esterases (Est-6 and Est-C) of various populations of Drosophila melanogaster and Drosophila simulans from Northern Greece were studied by means of starch gel electrophoresis, and the results are compared with those obtained from standard stocks. Two new alleles of the Est-6 locus of D. melanogaster and two new alleles of the Est-6 locus of D. simulans are described. The position of the Est-C locus in D. simulans is estimated. Evidence is presented for the genetic homology of the Est-C locus of D. melanogaster and the Est-C locus of D. simulans.     

Inheritance of enzymes and blood proteins in the leopard frog,Rana pipiens: Three linkage groups established

Individuals from natural populations of the leopard frog, Rana pipiens, were analyzed for electrophoretic differences in blood proteins and enzymes from an amputated digit. The proteins examined represent products of 72 loci. Presumptive heterozygotes at multiple loci were selected for experimental crosses. Mendelian inheritance of 18 protein variations were demonstrated in the offspring. Tests for linkage or independent assortment were performed for 75 locus pairs. Three linkage groups were established. Linkage group 1 contains two loci, aconitase-1 (Acon1) and serum albumin (Alb), with a 19% recombination frequency between them. Linkage group 2 contains four loci, glyoxalase (Gly), acid phosphatase-1 (Ap1), acid phosphatase-2 (AP2), and esterase-5 (Est5). The data show the relationships Gly-21.1%-AP1-0%-AP2-6.3%-Est5, and Gly-25.6%-Est5. Linkage group 3 consists of four closely linked esterase loci. The data, Est1-5.1%-Est6, Est6-1.8%-Est10-1.9%-Est4 and Est6-3.0%-Est4, do not establish a complete order but suggest that Est10 is between Est4 and Est6. These results, with data demonstrating apparent independent assortment of 67 other locus pairs, provide a foundation for establishing the frog genetic map.The project was supported by Grant No. RR-00572 from the Division of Research Resources, National Institutes of Health. This paper is contribution No. C-87 from the Amphibian Facility, George W. Nace, Director.     

Genetics of esterases in Drosophila. III. Influence of different chromosomes on esterase pattern in Drosophila

The present report presents the results of starch and polyacrylamide gel electrophoretic studies of the influence of the X chromosome on the expression of esterase-6 in D. melanogaster × D. simulans hybrids heterozygous for locus Est-6 as well as studies of the influence of autosomes on esterase expression in Drosophila of the virilis group. A differential expression of esterase-6 has been detected in D. melanogaster × D. simulans hybrid males. A differential decrease in the activity of esterase-6 (both F and S allozymes) derived from D. melanogaster has been noted. In hybrid females, the activity of parental esterases is the same. It is suggested that the X chromosome regulates the expression of esterase-6 in D. melanogaster. Analysis of individuals obtained in different schemes of crosses between different species of Drosophila of the virilis group by use of stocks marked with mutations in various chromosomes indicates that other autosomes (in particular, autosomes 4 and 5) also influence the phenotypic expression of esterases (which are controlled by genes located on the second chromosome).     

Linkage relationships and chromosomal locations of enzyme-coding genes in pepper,Capsicum annuum

The linkage relationships and chromosomal locations of 14 enzyme-coding genes were investigated in Capsicum annuum L. (garden pepper) by monitoring segregations in backcross and F₂ progeny of an interspecific cross between C. annuum cv. NM6-4 and C. chinense CA4 and by studying allele dosage effects in five hybrid primary trisomics. These conclusions can be reached: 6Pgdh-i is on the metacentric chromosome corresponding to the noir trisomie; Idh-1 and Est-3 are on chromosome 12; an aerocentric chromosome which corresponds to the pourple trisomie; Idh-1 is near the centromere and Est-3 is distal on the long arm of that chromosome. The other loci can be arranged in the following linkage groups and are apparently not located on the trisome corresponding to any of the trisomics tested: Est-4-18cM-(Pgi-1-3cM-Pgm-1); Prx-7-2cM-Tk-1; Pgm-2-2cM-Skdh-1; Est-1-OcM-Est-7. Linkage and dosage data combined with karyotype and meiotic analyses of the two species and F₁ hybrids suggest that Idh-1 and Skdh-1/Pgm-2 are near the breakpoints on the two chromosomes involved in a reciprocal translocation for which the two species differ. One locus, Pgm-3, was detected only in C. annuum cultivars and is apparently the result of a duplication of Pgm-2 which codes for cytosolic phosphoglucomutase activity. Pgm-2 and Pgm-3 are not tightly linked (approximately 20% recombination) which supports the proposal that Pgm-3 originated from a mechanism other than unequal crossing over. A comparison of the linkage relationships of enzyme-coding genes in pepper with those of putative orthologous loci in tomato reveals that two linkage blocks, Est-1-Est-7 and Pgi-1-Est-4, may have remained intact since the divergence of Capsicum and Lycopersicon.     

Linkage relationships of seven enzyme and two pigmentation loci in the snail Biomphalaria glabrata

Crossing experiments with inbred stocks of the snail (Biomphalaria glabrata) demonstrated that variants at two loci determining pigmentation and seven enzyme-determining loci exhibited normal Mendelian segregation ratios in F2 progeny. Among 39 pairwise comparisons for joint segregation, there was evidence of genetic linkage between a locus controlling mantle pigmentation (S) and 6-phosphogluconate dehydrogenase (Pgd) and confirmation of a previously described linkage between esterase-2 (Est-2) and catalase (Cat). Recombination fractions were estimated to be 17 +/- 4 for S-Pgd and 33 +/- 5 for Est-2-Cat. The remaining five loci--Acon-1, Pgm-1, Lap-1, Lap-2, and Pgd--assorted independently. This brings to 17 the number of loci examined for segregation and assortment in this medically important species. As Biomphalaria has a chromosome number n = 18, markers should soon be available for most or all of the linkage groups.     

Biochemical evidence of a translocation between 6 RL/7 RL chromosome arms in rye (Secale cereale L.). A genetic map of 6R chromosome

Summary The segregation of different isozymic loci was investigated in backcrosses and F₂s in rye. The leucin aminopeptidase-1 (Lap-1), Aconitase-1 (Aco-1), Esterase-6 (Est-6), Esterase-8 (Est-8), and Endopeptidase-1 (Ep-1) loci were linked. The Aco-1, Est-6, and Est-8 loci have been previously located on the 6RL chromosome arm. The Lap-1 locus has been located on the 6RS chromosome arm. The results favor the gene order: Lap-1... (centromere)... Aco-1... Est-8... Est-6... Ep-1. The isoelectric focusing separations of aqueous extracts from mature embryo tissue of wheat-rye addition and substitution lines involving the chromosomes of cereal rye Secale cereale L. confirmed the gene location of locus Ep-1 on the 6RL chromosome arm. Screening of wheat-rye addition lines involving the chromosomes of Secale montanum revealed that Ep-1 locus is not located on chromosome 6R of S. montanum. These results are the first biochemical evidence of the translocation between chromosome arms 6RL/7RL in the evolution of S. cereale from S. montanum.     

Linkage of the structural gene for uroporphyrinogen I synthase to markers on mouse chromosome 9 in a cross between feral and inbred mice

The Ups locus has been mapped to mouse chromosome 9 in a three-point cross. The observed gene order is centromere-Ups-15-Mpi-1-22-Mod-1. Ups is unlinked to Lv, which encodes the previous enzyme in the heme biosynthesis pathway. Feral mice collected at Skive, Denmark, have been characterized at several biochemical loci; multiple differences from inbred strains make this a useful stock for linkage analysis.Supported by USPHS Grants GM 24872 and GM 19521.     

Polymorphisms, Linkage and Mapping of Four Enzyme Loci in the Fish Genus Xiphophorus (Poeciliidae)

Electrophoretic variants at four additional enzyme loci--two esterases (Est-2, Est-3), retinal lactate dehydrogenase (LDH-1) and mannose phosphate isomerase (MPI)--among three species and four subspecies of fish of the genus Xiphophorus were observed. Electrophoretic patterns in F1 hybrid heterozygotes confirmed the monomeric structures of MPI and the esterase and the tetrametric structure of LDH in these fishes. Variant alleles of all four loci displayed normal Mendelian segregation in backcross and F2 hybrids. Recombination data from backcross hybrids mapped with Haldane's mapping function indicate the four loci to be linked as Est-2--0.43--Est3--0.26--LDH-1--0.19--MPI. Significant interference was detected and apparently concentrated in the Est-3 to MPI region. No significant sex-specific differences in recombination were observed. This group (designated linkage group II) was shown to assort independently from the three loci of linkage group I (adenosine deaminase, glucose-6-phosphate dehydrogenase, and 6-phosphogluconate dehydrogenase) and from glyceraldehyde-3-phosphate dehydrogenase and two isocitrate dehydrogenase loci. Evidence for conservation of the linkage group, at least in part, in other vertebrate species is presented.     

Genetic Analysis of Trichocyst Discharge of the Wild Stocks of Paramecium tetraurelia*

SYNOPSIS. Aberrant discharge of trichocysts in response to picric acid occurs in 8 of the 28 wild stocks of Paramecium tetraurelia. There are at least 4 distinguishable phenotypes: nondischarge, stocks 139, 163, 169, and 242; temperature-sensitive nondischarge, stock 126; leaky nondischarge, stock 203; and a clonally unstable phenotype, stocks 146 and 148. From each of these stocks a single recessive gene causing nondischarge has been isolated by backcrosses to stock 51. The original stocks 126, 146, and 148 possess other genes which affect the extracted genes. The copper resistance locus is ～ 10 centiMorgans from nd169 and nd242, but none of the other nondischarge genes are linked to 6 marker loci. The genes nd169 and nd242 are only 0.5 centiMorgans apart making them the closest known pair of loci in P. tetraurelia. The genes nd126 and nd242 are distinguishable alleles at the same locus and the genes nd146 and nd148 are apparently identical alleles. The large number of loci involved in producing a similar phenotype in different stocks supports the idea that mutation is much more important than gene flow in this highly inbreeding species.     

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.     

Association of four isozyme loci with a reciprocal translocation between 1R/4R chromosomes in cultivated rye (Secale cereale L.)

Summary The progeny of four crosses between a structural heterozygote for a reciprocal translocation and a homozygote for the standard chromosome arrangement were analyzed in rye (Secale cereale L. cv Ailés) for the electrophoretic patterns of eight different leaf and endosperm isozymes and also for the meiotic configuration at metaphase I. The Pgi-1, 6-Pgd-2 and Mdh-1 loci are linked to each other and also to the reciprocal translocation. These loci have been located on chromosome 1R. The Mdh-1 locus is located in the interstitial segment of chromosome 1R, between the centromere and the breakpoint. The Pgm-1 locus has been located on chromosome arm 4RS and is linked to Pgi-1, 6-Pgd-2, Mdh-1 and the reciprocal translocation. The estimated distance between the Pgm-1 locus and the centromere is 14.98 ± 2.27 cM. Therefore, the reciprocal translocation involves the 1R and 4R chromosomes. Other linked loci detected have been Mdh-2b and Est-2 (7.40 ± 2.90 cM) and Got-3 and Est-2 (5.62 ± 3.07 cM). These three last loci are located on chromosome 3R and their order most probably is Mdh-2b — Est-2 — Got-3.     

Effects of selection for resistance to organophosphorus insecticides on two esterase loci in Drosophila melanogaster

Two laboratory populations of Drosophila melanogaster were exposed to the insecticides ethyl-parathion and fenthion respectively. Three parameters were studied in each generation: resistance to the insecticide (LC 50), AChE activity, and allele frequencies at the Est-6 locus. In both treated populations a significant increase in the resistance was observed within a few generations. This rise in the resistance levels was accompanied by parallel changes in the two esterases AChE and Est-6. With AChE the enzyme activity became considerably higher indicating either structural modification of the enzyme molecule or mutations in the regulatory system of the AChE gene locus. At the Est-6 locus the S allele was eliminated during the selection process which might be due to greater sensitivity of the Est-6^S allozyme.     

Characterization of Esterases in a Brazilian Population of Zaprionus Indianus (Diptera: Drosophilidae)

The aim of this study was to characterize esterases in Zaprionus indianus, a drosophilid recently introduced into Brazil. A further aim was study the variation of activity of esterases in the presence of inhibitors and their expression according to sex, sexual activity and age of individual flies. Polymorphisms were detected in two esterase loci (Est-2 and Est-3) and monomorphisms in four others (Est-1, Est-4, Est-5 and Est-6). Biochemical tests using α- and β-naphthyl acetate and the inhibitors malathion, eserine sulphate and PMSF allowed us to classify EST-2 and EST-5 as β-esterases, both carboxyl-esterases, and EST-1, EST-3, EST-4 and EST-6 as α-esterases. EST-1 and EST-3 were classified as carboxyl-esterases and EST-4 and EST-6 as cholinesterases. EST-5 activity was more pronounced in males and EST-2 was restricted to them or to recently copulated females. EST-4, rarely detected, was not characterized. Based on their biochemical characteristics possible roles for these enzymes are suggested.     

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.