A new variant of the Es-4 locus in the rat

A new variant of kidney esterase in the DK/Nac rat strain is reported. The new esterase was tentatively named ES-4C determined by a third allele of the Es-4 locus of Linkage Group V (LGV). Strain distribution was surveyed using 17 inbred strains, but no strain except for the DK/Nac strain possessed the ES-4C type. Although we surveyed outbred stocks (Jcl: Wistar and Jcl: SD) we could not find rats carrying the ES-4C type. Genetic analysis of the ES-4C type was carried out using mating experiments between DK/Nac and BUF/Nac (ES-4B). The results indicated that the new variant was controlled by the Es-4 locus and it was named the Es-4c allele.     

用19个生化基因位点研究普通级Z:ZCLA长爪沙鼠的遗传多样性

目的调查Z:ZCLA长爪沙鼠原种群普通级长爪沙鼠的遗传多样性。方法用本实验室自行建立的长爪沙鼠19个生化基因位点的乙酸纤维素膜电泳技术并结合基本群体遗传学指标研究了普通级Z:ZCLA长爪沙鼠100个家系的遗传多态性。结果Z:ZCLA长爪沙鼠在Es-1、Car-2、Hbb、Gpi-1、Cs-1、Ce-2I、dh-l、Mod-1呈单态,在Es-2、Es-3、Es-4、Es-6、Es-8、Es-9、Es-10、pd-1、gm-1、Trf、Akp-1个位点上呈现多态性,等位基因从2~4个不等,平均等位基因数3.0,平均杂合度0.512,平均多态信息量0.455。结论提示目前本群遗传多样性水平处于中度多态。     

Genetic variability within and between outbred Wistar strains of rats.

The allelic frequencies at 6 isozyme loci (Es-1, Es-2, Es-3, Es-4, Es-Si and Amy-1) were examined in 4 outbred Wistar strains and additionally 2 SD strains as controls. From the allelic frequencies, the averages of the heterozygosities in individual strains and the geometric genetic distances between every pair of all possible strain combinations were calculated. The averages of the heterozygosities in 2 SD strains were both intermediate (around 0.2) and the genetic distance between them was rather short. But among the Wistar strains, the averages of the heterozygosities were highly variable and the genetic relationships among them were very variable in their genetic distances. From these results, it was suggested that the outbred Wistar strains were different each other in their genetic constitutions and that no suggestion was obtained to descriminate genetically the Wistar strains from the SD strains.     

Es-6, a further polymorphic esterase in the rat

A further polymorphic rat esterase with broad tissue expression and restricted substrate specificity is described and tentatively called Es-6. Inbred rat strains have either fixed allele Es-6^F or fixed allele Es-6^S. Es-6 is not linked to the established esterase cluster consisting of the eight esterase loci Es-1, Es-2, Es-3M, Es-4M, Es-4W, Es-5 (=Es-3W), Es-7, and Es-8 in LG V of the rat or to RT1, Gc, c, a, and h. Esterases with apparently identical biochemical and genetical characteristics are Es-17 of the mouse and Es-A4 of humans.Supported by the Deutsche Forschungsgemeinschaft (Be 352/13 and Gu 105).     

Re-evaluation of LG V of the rat and assignment of 12 carboxylesterases to two gene clusters

Examining the strain distribution pattern of the recombinant inbred strain series LXB and DXE and of backcross progeny of (LEW X LE)F1 X LEW, (LEW X BN)F1 X LEW, and (LEW X BN)F1 X BN for esterase markers, including three carboxylesterase allozymes (ES-15, ES-16, ES-18), hitherto not studied genetically, revealed the existence of two esterase gene clusters within LG V: cluster 1, containing Es-2, Es-8, Es-10, Es-3, Es-7, Es-9, and separated by 8.8 +/- 1.3 cM from cluster 2, containing Es-1, Es-14 (formerly Es-Si), Es-15, Es-16, and Es-18. Analyses of 93 inbred strains of rats showed only 12 and 6 haplotypes for cluster 1 and cluster 2, respectively, indicating a strong linkage disequilibrium. These data and serotyping results of one backcross population for the RT2 blood group system lead to a re-evaluation of linkage group V. Including literature data the following gene order is suggested: RT2 - (7.1 +/- 1.8) Es-2, Es-4, Es-8, Es-10 (2.7 +/- 0.7) Es-3, Es-7, Es-9 (8.8 +/- 1.3) Es-1, Es-14, Es-15, Es-16, Es-18.     

Genic heterogeneity and genetic monitoring of mouse outbred stocks.

An outbred stock of Swiss:SE mice has been surveyed for genic heterogeneity at 12 loci, encoding biochemical polymorphisms in mice. Using horizontal starch-gel electrophoresis, 6 loci (Es-1, Es-2, Es-3, Es-5, Trf, Dip-1) revealed no genic heterogeneity within the total sample of 289 male mice examined. The other 6 loci (Mpi-1, Mup-1, Hbb, Gpi-1, Pgm-1, Ldr-1) each showed a 2-allelic variation within each of the 3 stock units (pavillions) involved. A pavillion effect on the observed genotype numbers was found for Pgm-1 and Gpi-1 (P less than 0.10). Inadequate genotyping may have occurred at Gpi-1 and Ldr-1, as suggested by a 'week effect' on the observed genotype numbers (P less than 0.05). For studying long-term genetic changes within outbred stocks, a routine monitoring procedure using biochemical polymorphisms is recommended.     

Detection of quantitative trait loci for backfat thickness and intramuscular fat content in pigs (Sus scrofa).

In an experimental cross between Meishan and Dutch Large White and Landrace lines, 619 F(2) animals and their parents were typed for molecular markers covering the entire porcine genome. Associations were studied between these markers and two fatness traits: intramuscular fat content and backfat thickness. Association analyses were performed using interval mapping by regression under two genetic models: (1) an outbred line-cross model where the founder lines were assumed to be fixed for different QTL alleles; and (2) a half-sib model where a unique allele substitution effect was fitted within each of the 19 half-sib families. Both approaches revealed for backfat thickness a highly significant QTL on chromosome 7 and suggestive evidence for a QTL at chromosome 2. Furthermore, suggestive QTL affecting backfat thickness were detected on chromosomes 1 and 6 under the line-cross model. For intramuscular fat content the line-cross approach showed suggestive evidence for QTL on chromosomes 2, 4, and 6, whereas the half-sib analysis showed suggestive linkage for chromosomes 4 and 7. The nature of the QTL effects and assumptions underlying both models could explain discrepancies between the findings under the two models. It is concluded that both approaches can complement each other in the analysis of data from outbred line crosses.     

Esterase-30 (ES-30) of the house mouse: Biochemical characterization and genetics of a new carboxylesterase isozyme linked to cluster-2 loci on chromosome 8

A new carboxylesterase isozyme (EC 3.1.1.1), designated ES-30, is described in mouse liver. Two phenotypes were distinguished, ES-30A, a possible null type, was found in SPE/Pas and in other lines derived fromMus spretus, and ES-30B was found in BALB/cJ and other laboratory inbred strains. ES-30B is characterized by a distinct electrophoretic band when stained using 5-bromoindoxyl acetate as the substrate. After isolation and purification from other esterases by ion-exchange chromatography and molecular sieving, the molecular mass was estimated by two independent methods to be 62 and 64 kDa, respectively. The activity of ES-30B is higher in adult males than in females and can be stimulatedin vivo by testosterone. The distribution of phenotypes on the progeny of a backcross series suggests a separate locus,Es-30, with the allele a for absence andb for presence of the isozyme. LocusEs-30 is shown to be closely linked toEs-2 and toEs-7 of cluster-2 on chromosome 8. The gene orderEs-9—Got-2—(Es-2, Es-7, Es-30) is suggested. This work was supported by the Deutsche Forschungsgemeinschaft. This is communication No. 72 of a research program devoted to the cellular distribution, genetics, and regulation of nonspecific esterases.     

Mapping of rabbit microsatellite markers using chromosome-specific libraries

Recently, rabbit microsatellite markers were developed from a chromosome 1-specific library, and seven new markers were incorporated into the genetic map of the rabbit. We have now developed microsatellite markers from chromosomes 3-, 5-, 6-, 7-, 12-, and 19-specific libraries. Linkage analysis was performed with use of these new markers, five recently physically mapped markers (PMP2, TCRB, ALOX15, MT1, and Sol33), microsatellite markers located in the HBA gene cluster, the MHC region and FABP6 gene, and seven biochemical markers (Es-1, Es-3, Est-2, Est-4, Est-6, Est-X, and HP). This analysis enabled us to verify the specificity of the libraries and to determine the position and orientation of the linkage groups on the chromosomes.     

Occurrence of the heterozygosity at Es-1 locus in a sub-strain of the NZB mice]

In the course of inspection of the biochemical marker genes in inbred strains of mice maintained in our laboratory, a female mouse of the NZB strain was found to be heterozygous for the Es-1 locus. Namely, it was Es-1a/Es-1b type. After this finding, many heterozygous mice were found among her sisters and the descendants. However, these heterozygotes (Es-1a/Es-1b) showed no heterozygosity for other 11 characters, i.e., the 6 biochemical markers (Hbb, Trf, Es-2, Id-1, Mod-1, Gpd-1) and the 5 coat colour markers (A, B, C, D, AND S) were idential as those previously described. It was, moreover, observed that they possessed the immunological characteristics typical of the NZB mice. Therefore, it could be concluded that the heterozygosity had been originated from a single mutation at the Es-1 locus, i.e., from Es-1a to Es-1b or vice versa. With regard to the alleles at the Es-1 locus, an investigation was carried out in two sub-strains of the NZB mice having different breeding history and the followings were clarified. One substrain imported from Karolinska Institute, Sweden, had been fixed with the Es-1a allele and the other imported from England was found to be Es-1b/Es-1b type. The NZB mice which displayed the heterozygosity had been derieved from the Karolinska sub-strain. Importance of biochemical marker genes for inspection of proper maintenance of inbred strains has been discussed.     

A fourth allele in the plasma esterase-1 (Es-1) system of the domestic fowl

Plasma samples of fowl were analysed by horizontal polyacrylamide gel electrophoresis (pH 9.0). Evidence was presented for the subdivision of an earlier reported esterase-1 allele (Es-1A) into two alleles designated Es-1A1 and Es-1A2. Family data were consistent with the hypothesis that the Es-1 phenotypes were controlled by four codominant, autosomal alleles Es-1C, Es-1A1, Es-1A2 and Es-1B). The White Leghorn samples showed high frequency of Es-1A1 (about 0.7) and also had considerable frequency of Es-1A2 (0.2) and of Es-1B (0.1). The three meat-type breeds studied (White Plymouth Rock, Rhode Island Red and New Hampshire) showed a very high frequency of Es-1B (0.8-1.0).     

Linkage of faded gene (fe) to chromosome 6 of the mouse

Linkage tests on the faded gene were carried out with some coat color and biochemical markers, It was shown that the faded locus was not closely linked to the following loci: Idh-1 (chromosome 1), a (2), Car 2 (3), Mup-1 (4), Pgm-1 (5), Hbb (7), Gpi-1 (7), Es-1 (8), Trf (9), Es-3 (11), s (14), Sod-1 (16) and Ce-2 (17). The mutant locus showed linkage with Ggc on chromosome 6.     

Esterase 13, a new mouse esterase locus with recessive expression and its genetic location on chromosome 9

A new esterase locus (Es-13) has been identified in Mus musculus. Strains AEJ/GnRk, LG/J, SJL/J, and SWR/J carry a recessive allele, Es-13 ^b, for a locus possibly involved in the posttranslational modification of a kidney esterase. All other strains observed carried the dominant Es-13 ^a allele. Es-13 was mapped on Chr 9 by recombinant inbred lines and by conventional backcrossing experiments. Backcross data produced the following gene order and map distances: Lap-1 (31.6±7.5 cM) Es-13 (2.6±2.6 cM) Mod-1.     

Genetic Analysis and Mapping of Biochemical Markers in an F2 Intercross of Two Inbred Strains of the Rabbit (Oryctolagus cuniculus)

A total of 40 biochemical and four immunological markers found to be polymorphic in the rabbit in previous studies were screened in the AX/JU and IIIVO/JU inbred strains. Although the strains are considered unrelated, only eight (biochemical) markers were found to be polymorphic between the two strains. These eight markers were analyzed in an F₂ intercross population. Linkage was found for Est-5 and C on chromosome 1 and for Es-1, Est-2, Est-4, Est-6 and HP on linkage group VI. Two polymorphic markers, Es-3 and Mhr-1 could not be linked to any of the other markers.     

Analysis of quantitative trait loci using hybrid pedigrees: quantitative traits of animals

A method is proposed for analysis of quantitative traits in animal hybrid pedigrees formed by crosses between outbred lines differing in allele frequencies of the genes controlling the trait studied. The method is based on the decomposition of trait variances into components and uses maximization of the likelihood function for estimating model parameters, which allows the estimation of additive and dominance effects of the gene involved in trait determination and its allele frequencies, as well as determination of the chromosomal position of this gene relative to genotyped markers. To test the linkage of this gene with markers, a statistic with the noncentral chi(2) distribution has been chosen. Analytical expressions for the power of this method have been derived. The method has been tested on small model hybrid pedigrees. Phenotypic values of the trait and information on marker genotypes for each individual in hybrid pedigrees are original data for the analysis of a quantitative trait.     

Mapping of theEs-4 locus and linear order of esterase genes (linkage group V; LGV) in the rat

There are three different linear orders of esterase loci of linkage group V (LGV) in the rat (Rattus norvegicus). The first is Es-2-Es-3-Es-1, the second Es-3-(Es-2,Es-4)-Es-1, and the third Es-3-Es-2-Es-1-Es-4. We carried out mating experiments to define the order clearly. Linkage analyses of the four esterase loci, Es-1, Es-2, Es-3, and Es-4, were carried out using two inbred strains carrying different alleles at the four loci. Six locus combinations examined in this study were as follows: Es-1-Es-2, Es-1-Es-3, Es-1-Es-4, Es-2-Es-3, Es-2-Es-4, and Es-3-Es-4. The recombination frequencies of each combination were 6.3, 6.3, 6.3, 5.2, 1.8, and 3.4%, respectively. The first recombination between Es-2 and Es-4 was observed. We propose that the esterase loci of LGV be classified into three clusters according to distances between the loci. The linear order of the four loci is shown to be as follows: [Es-3] (cluster II)-3.4 +/- 2.4%-[Es-4-1.8 +/- 1.7%-Es-2] (cluster III)-6.3 +/- 6.1%-[Es-1] (cluster I).     

Enzyme polymorphism in the European starling: Study on plasma esterases

In plasma of the European starling (Sturnus v. vulgaris L.), genetic variation was detected by polyacrylamide gel electrophoresis. Two esterase zones, of which one is polymorphic, had already been described earlier. In addition to these two zones (Es-1 and Es-3), we describe a third (Es-2) that also showed variations. The distribution of the phenotypes observed in the Es-2 zone closely fits the expected distribution according to the law of random mating so that the polymorphism of Es-2 is hereditary. This Es-2 locus is postulated to be a codominant system, controlled by two alleles.     

Esterase-23 (ES-23): Characterization of a new carboxylesterase isozyme (EC 3.1.1.1) of the house mouse,genetically linked to ES-2 on chromosome 8

Genetic variation of a carboxylesterase isozyme (EC 3.1.1.1) of the house mouse, designated ES-23, is described. ES-23 was found in kidney, liver, and intestine. The isozyme was resistant to inhibition by 10(-3) mol/liter eserine and was stained using alpha-naphthyl butyrate or 5-bromoindoxyl acetate as substrate. Five different phenotypes, ES-23A to ES-23E, could be distinguished by disc electrophoresis and by isoelectric focusing. ES-23 is controlled by a structural locus situated within the esterase gene cluster 2 on chromosome 8. An analysis of allele distribution among different strains suggested a separate structural locus for the isozyme, Es-23e, which is closely linked to the loci Es-2, Es-5, Es-7, and Es-11. Of the five phenotypes, only ES-23B was expressed in lung. This variation is apparently controlled by a cis-acting regulatory element, presumably a temporal locus, Es-23t, closely linked to the presumed structural locus Es-23e.     

Esterase polymorphisms in Microtus ochrogaster: interaction and linkage

Three polymorphic loci have been identified in the prairie vole, Microtus ochrogaster. Together they control a group of plasma esterases which can be separated using starch gel electrophoresis. A structural locus, Es-1, produces an enzyme which from genetic evidence appears to be a dimer. The allele Es-1 ^a produces a wholly active subunit, and homozygotes give a single enzyme band. The product of the second allele, Es-1 ^o, cannot form active enzyme on its own but will dimerize with the Es-1 ^a subunit, giving a hybrid enzyme with a slower electrophoretic mobility than the pure Es-1 ^a enzyme. The third allele, Es-1 ^–, has no detectable product. A second structural locus, Es-2, is linked to Es-1. The allele Es-2 ^a produces a single enzyme band, but the second allele Es-2 ^– has no detectable product. A modifier locus, Me, changes the mobility of the Es-1 enzymes. Me ^f is dominant over me ^s, and in homozygotes for me ^s the mobility is reduced.This work was supported by National Science Foundation Grant GB6273.This is contribution No. 869 from that Department.     

Comparative Autosomal Linkage in Mammals: Genetics of Esterases in MUS MUSCULUS and RATTUS NORVEGICUS

Recombination between Esterase-4 and Esterase-2 in the rat was not observed in 278 backcross offspring. Es-4 is thus included within the "esterase cluster" in Linkage group V. A new map of this region was constructed and the relationship of the four esterase loci was found to be: Es-4-(9.6+/-1.6 cM)-Es-2, Es-4-(1.5+/-0.7cM)-Es-3. Homology of this region with a region of Linkage Group XVIII (Chromosome 8) of the mouse was proposed on the basis of tissue distribution, subcellular localization and response of enzymes to inhibiotrs. Specifically, rat Es-1 was suggested as the homolog of mouse Es-6. An autosomal segment comprising at least 15cM of the rat and mouse genomes appears to have remained relatively intact with respect to genetic content during rodent speciation. In addition, a new polymorphism for mouse esterase was described. The locus was designated Esterase-10 (Es-10) and proposed as the mouse homolog of human Esterase D. Linkage of Es-10 with nucleoside phosphorylase-1-(Np-1) on Chromosome 14 was established.