Showing papers in "Biochemical Genetics in 1987"

Rapid isolation of animal mitochondrial DNA in a small fixed-angle rotor at ultrahigh speed.

Abstract: In recent years, mitochondrial DNA (mtDNA) sequence analysis has become a powerful tool for the investigation of the evolutionary and population biology of various animal species (Wilson et al., 1985). Most such studies have relied on physical purification of mtDNA, typically by ultracentrifugation in cesium chloride gradients. Thorough descriptions of such methods are given by Lansman et al. (1981) and Wright et al. (1983). Practical concerns over the expensive instrumentation and extensive time required by such methods have been expressed by several workers (e.g., Grill et al., 1983; Powell and Zufiiga, 1983). Several of our colleagues have expressed doubt that purified mtDNA samples can be generated in a reasonable time in numbers sufficient to perform large-scale population studies. We describe here an ultracentrifugal procedure that yields homogeneous mitochondrial DNA from as many as i0 samples in as little as 10 hr. The procedure uses a relatively inexpensive tabletop ultracentrifuge and relies on a self-forming cesium chloride gradient generated in a small fixed-angle rotor that operates at a speed of 100,000 rpm and a relative centrifugal force of 436,000g.

Immunochemical characterization of human red cell acid phosphatase isozymes.

Abstract: An immunological study was performed on human red cell acid phosphatase (ACP1) isozymes encoded by different alleles, each of which is expressed as an electrophoretically fast (f) isozyme and a slow (s) isozyme. These isozymes reacted as two immunochemically different groups. Allele-specific reactions were not detected between either the f isozymes or the s isozymes. Quantitation of ACP1 isozymes in red cells by crossed immunoelectrophoresis revealed a phenotype-dependent variation in the concentration of isozyme protein. A simple gene dosage effect was indicated and the ordering of the ACP1 alleles (ACP1*A < ACP1*B < ACP1*C < ACP1*E) was identical to that found for enzyme activity levels. Also, an allele effect on the proportion between s and f isozymes (s/f) was observed; the ordering here was ACP1* B < ACP1*A < ACP1*, which is the same as that reported for the susceptibility to modulation with purines. These variations in isozyme protein levels appear to account for the phenotypic differences in the intensity of the isozyme bands, when activity-stained after electrophoresis, and in the red cell enzyme activity levels. Investigation of two carriers of a Null allele showed no evidence of an aberrant protein product, and half-normal concentrations of enzyme protein were observed in the red cells of these individuals.

A multiple homogenizer for rapid sample preparation in immunoassays and electrophoresis

Abstract: A multiple homogenizer is described for preparing samples of small invertebrates or tissue in a flat-bottom immunoplate. Its efficiency was evaluated by immunoassay of a carboxylesterase (E4), the enzyme conferring insecticide resistance in the peach potato aphid (Myzus persicae). This equipment was shown to release more enzyme, with less variability, than homogenizing individual aphids and its efficiency allows one person to analyze up to 3000 individual insects per day. It is also suitable for preparing samples for electrophoretic analysis. In the present study samples were loaded onto electrophoresis gels rapidly and accurately by using an eight-channel multi-pipette.

Genetic analysis of murine strains C57BL/6J and C3H/HeJ to confirm the map position of Ath-1, a gene determining atherosclerosis susceptibility

Abstract: Previous results suggested that strains C57BL/6J and C3H/HeJ differed in a single gene for atherosclerosis susceptibility, calledAth-1. Based on data from recombinant inbred strainsAth-1 was tentatively assigned to chromosome 1 linked toAlp-2. In this report, a cross between C57BL/6 and C3H/HeJ was carried out in order to test whether the tentative map position was correct. Parental strains and F1 and F2 progeny were examined. Susceptible alleles ofAth-1, found in C57BL/6, are associated with relatively low levels of high-density lipoprotein (HDL)-cholesterol in animals fed an atherogenic diet; resistant alleles ofAth-1 are associated with relatively high levels of HDL-cholesterol. F1 progeny have HDL levels that are intermediate between these of the two parental strains. Among the F2 progeny,Alp-2 andAth-1 cosegregated, providing confirmatory evidence thatAth-1 is linked toAlp-2 on chromosome 1. Three mice recombinant forAlp-2 andAth-1 were found among the 60 chromosomes tested, giving an estimated map distance between these two genes of 5.0±2.8 (SE) cM. The phenotypic characteristics ofAth-1 resemble a genetic trait in humans, hyperalphalipoproteinemia, which is characterized by elevated levels of HDL-cholesterol, reduced risk of heart disease, and increased longevity.

Chromosomal location of genes coding for endosperm proteins of Hordeum chilense, determined by two-dimensional electrophoresis of wheat-H. chilense chromosome addition lines.

Abstract: The proteins of Hordeum chilense grain were resolved into 25 major components by two-dimensional electrophoresis. Their solubilities in aqueous alcohol solutions were determined to distinguish prolamin storage proteins from metabolic and structural proteins. The prolamins were divided into two groups, based on the presence or absence of intermolecular disulfide bonds determined by gel-filtration chromatography. Using an incomplete set of Chinese Spring wheat-H. chilense disomic addition lines, the structural genes of 21 of the 26 most dominant seed proteins were assigned to chromosomes. The great majority of the prolamin genes, including those coding for a high molecular weight (HMW) prolamin subunit, was present on chromosome 1Hch. However, a small number of prolamin genes also occurred on chromosomes 5Hch and 7Hch. A minor protein, probably belonging to the nonstorage group of proteins, is coded by genes on 5Hch. Various ditelosomic addition lines and ditelosomic and disomic substitution lines for chromosome 7Hch were also analyzed by electrophoresis. This technique revealed that the genes for three major prolamins occur on the β arm of chromosome 7Hch and that a gene for a minor protein, also thought to be a prolamin, occurs on the α arm. These results are discussed in relation to the evolution of prolamin genes in the Triticeae.

Characterization and genetic control of the prolamins of Haynaldia villosa: Relationship to cultivated species of the Triticeae (rye, wheat, and barley)

Abstract: Haynaldia villosa is a wild grass of the tribe Triticeae, other members of which include the cultivated cereals barley, rye, and wheat. We have made an electrophoretic and chemical characterization of the major seed storage proteins (prolamins) of H. villosa and determined the chromosomal locations of the structural genes for some components using the available wheat/H. villosa chromosome addition lines. As in wheat, barley, and rye, groups of high molecular weight (polymeric), sulfur-poor (monomeric), and sulfur-rich (monomeric gamma-type and polymeric) prolamins can be recognized. Most of the components are encoded by genes on chromosome 1 Ha, which is homologous with the chromosomes controlling many of the prolamins in wheat and rye and all of those in barley. In addition, H. villosa also contains alpha-type sulfur-rich prolamins, previously detected only in wheat and its close relatives. These may be encoded by genes on chromosome 6Ha, which is homologous with the group 6 chromosomes that control the alpha-type gliadins of wheat. Despite the proposed close relationship between Haynaldia and ryes, no evidence was found for the presence of proteins closely related to the Mr 75,000 gamma-secalins which are characteristic of wild and cultivated species of Secale.

Contrasting patterns of geographic variation in the cosmopolitan sibling species Drosophila melanogaster and Drosophila simulans.

Abstract: An electrophoretic study was carried out to compare the geographic pattern of genetic variation in Drosophila simulans with that of its sibling species, Drosophila melanogaster. An identical set of 32 gene-protein loci was studied in four geographically distant populations of D. simulans and two populations of D. melanogaster, all originating from Europe and Africa. The comparison yielded the following results: (1) tropical populations of D. simulans were, in terms of the number of unique alleles, average heterozygosity per locus, and percentage of loci polymorphic, more variable than conspecific-temperate populations; (2) some loci in both species showed interpopulation differences in allele frequencies that suggest latitudinal clines; and (3) temperate-tropical genetic differentiation between populations was much less in D. simulans than in D. melanogaster. Similar differences between these two species have previously been shown for chromosomal, quantitative, physiological, and middle-repetitive DNA variation. Estimates of N m (number of migrants per generation) from the spatial distribution of rare alleles suggest that both species have similar levels of interpopulation gene flow. These observations lead us to propose two competing hypotheses: the low level of geographic differentiation in D. simulans is due to its evolutionarily recent worldwide colonization and, alternatively, D. simulans has a narrower niche than D. melanogaster. Geographic variation data on different genetic elements (e.g., mitochondrial DNA, two-dimensional proteins, etc.) are required before these hypotheses can be adequately tested.

Genetic variability in mitochondrial DNA in a regional population of the great tit (Parus major).

Abstract: Genetic variation of mitochondrial DNA (mtDNA) in 18 great tits (Parus major) from three neighboring localities in Sweden was investigated with eight tetranucleotide restriction endonucleases. The 18 individuals could be separated into 13 different maternal lineages. The high number of female lineages present in this regional population contrasts with a low level of sequence divergence between the different mtDNA clones, with a mean of 0.19% sequence divergence between all individuals. There was no obvious spatial structuring of mtDNA clones among the three localities. The presence of a high number of different clones with a low degree of sequence divergence could be explained by the effects of a large long-term effective population size, with the mtDNA clones having diverged about 25,000–200,000 years ago.

Genetic analysis of strains C57BL/6J and BALB/cJ for Ath-1, a gene determining atherosclerosis susceptibility in mice.

Abstract: We previously reported that mice have at least one major gene determining atherosclerosis susceptibility, Ath-1. Susceptible alleles of Ath-1 are found in strain C57BL/6J and are associated with relatively low levels of high-density lipoprotein cholesterol (HDL-C) when these mice are fed an atherogenic diet. Resistant alleles of Ath-1 are found in strains C3H/HeJ and BALB/cJ and are associated with relatively high levels of HDL-C. Data reported earlier from the set of seven recombinant inbred (RI) strains, derived from C57BL/6By and BALB/cBy, showed that these parental strains differed at Ath-1. However, due to the limited number of RI strains, it was not possible to determine with certainty whether Ath-1 was the only major gene determining atherosclerosis susceptibility in these two strains or to determine its map position accurately. In this report, examination of F1, F2, and backcross progeny from a cross between C57BL/6J and BALB/cJ demonstrates that Ath-1 is the major gene determining atherosclerotic lesion formation and HDL-C levels in female mice. The data from male animals suggest that environmental factors or modifying genes also influence male HDL-C levels and thus partly obscure the Ath-1 phenotype. HDL-C levels in F1 progeny resemble the BALB/c parent. The data from the cross provide confirmatory evidence that Ath-1 is linked to Alp-2 on chromosome 1 with a map distance of 4.8 +/- 2.3 (SE). Combining these data with a previous cross between strain C57BL/6 and strain C3H/HeJ gives a map distance between Ath-1 and Alp-2 of 4.9 +/- 1.8 based on 7 crossovers found among 144 tested chromosomes.

Electrophoretic analysis of genetic linkage in Scots pine (Pinus sylvestris L.)

Abstract: Eighty megagametaphytes from each of 24 Scots pines (Pinus sylvestris L.) were subjected to horizontal starch gel electrophoresis. The trees were from crosses among widely separated provenances, and each was polymorphic for 8 to 14 loci. Evidence for linkage among 275 two-locus combinations was tested using chi-square analysis. Data from different trees were pooled to calculate map distances for the species. Nineteen of the twenty-nine loci tested were linked in one of six groups; the groups varied in size from two to seven loci. Similarities in linkage relationships among Scots pine, other pines, and other species within the Pinaceae support karyological research that suggests extensive conservation of the conifer genome.

Purification of the glutamine synthetase II isozyme of Drosophila melanogaster and structural and functional comparison of glutamine synthetases I and II

Abstract: Glutamine synthetase II was purified from Drosophila melanogaster adults. It was completely separable from the isozyme glutamine synthetase I by means of DEAE chromatography. The complete enzyme has an apparent molecular weight of 360,000. After two-dimensional electrophoresis it gave a single molecular species with an apparent molecular weight of 42,000. Structural analysis of the two isozymes showed that they are different both in subunit molecular weight and in isoelectric point. Peptide maps of the purified subunits showed considerable dissimilarity. Glutamine synthetase II is more active than glutamine synthetase I in the transferase assay, while the opposite is true in the biosynthetic assay. The kinetic parameters were determined, showing again noteworthy differences between the two isozymes. We therefore conclude that two forms of glutamine synthetase are present in Drosophila, with different primary structures, different kinetic behavior, and the possibility of different functional properties.

Polymorphisms of four hepatic cytochromes P-450 in twenty-eight inbred strains of rat.

Abstract: Two-dimensional gel electrophoresis of hepatic microsomes from phenobarbital-treated animals was used to analyze electrophoretic/regulatory polymorphisms for cytochromes P-450b, P-450e, P-450g, and P-450h in 28 inbred strains of rat. Previous studies with outbred rats revealed the existence of four electrophoretic variants for P-450b, two for P-450e, and three for P-450h as well as two regulatory alleles for P-450g. With the exception of one allozymic form of P-450h, all of these alleles as well as a novel (null) allele for P-450e were found to be homozygous in at least two of the inbred strains tested. Eight phenotypes for combinations of these four cytochromes P-450 were observed. Inbred strains were identified that can be used in studies on the structure/function of unique cytochrome P-450-allozymes and in genetic crosses to map the four distinct cytochrome P-450 genes.

The aryl hydrocarbon hydroxylase (Ah) locus and a novel restriction-fragment length polymorphism (RFLP) are located on mouse chromosome 12.

Abstract: The aryl hydrocarbon hydroxylase (Ah) locus that controls the induction of chemical carcinogen-metabolizing enzymes in mice has been found to be linked to a new restriction-fragment length polymorphism (RFLP). Only C57 BL/6 and closely related inbred strains displayed a 7.6-kbHindIII restriction fragment, while all other inbred strains tested displayed an 11.2-kbHindIII restriction fragment when using plasmid pRC2.3 as the hybridization probe. Polymorphisms in this region can also be detected with two other restriction enzymes:SacI andEcoRV. Linkage ofAh and the restriction-fragment length polymorphism was first detected using the BXD (C57BL/6 × DBA/2) recombinant inbred strains and was confirmed by a backcross. Both the restriction-fragment length polymorphism andAh were not linked to the standard genetic markersHba, Hbb, b, d, C-3, andW. However, comparison of the RFLP strain distribution pattern in the BXD recombinant inbred set with the strain distribution pattern of another RFLP, known to be located on chromosome 12, shows complete concordance in 24 of 24 strains, thereby locatingAh on chromosome 12.

Human red cell acid phosphatase (ACP1): evidence for differences in the primary structure of the two isozymes encoded by the ACP1*B allele.

Abstract: One of the notable features of human red cell acid phosphatase (ACP1, E.C. 3.1.3.2) is the generation of 2 isozymes (f and s) by each allele. These isozymes differ with respect to electrophoretic mobility (fig. 1) as well as to catalytic, stability and immunochemical properties (Harris 1980, Dissing 1987). The mechanism responsible for this pair wise production of isozymes has long been a puzzle and is of interest not only to the biochemist and geneticist but also to the forensic scientist.

Identification of shiitake genotypes by multilocus enzyme electrophoresis: Catalog of lines

Abstract: Starch gel electrophoresis of allozymes extracted from mycelium grown in submerged culture was used to identify and catalog lines ofLentinula edodes. Variability at 11 multiallelic loci was used to separate 91 lines collected from worldwide sources into 35 genotypic clases. Genotypic class 2 was the largest, with 18 lines; 18 other genotypic classes contained more than one line; and 16 genotypic classes contained only one line each. Three hybrids, with potential commercial value, were produced by crossing single-spore-derived monokaryons of different genotypes. Each of the three hybrids could be differentiated from the above 35 classes based on their multilocus allelic combinations. Multilocus enzyme analysis should aid the description, registration, and licensing of improved shiitake cultivars.

Ribosomal DNA sequences attached to the nuclear matrix

Abstract: The organization of rat liver ribosomal DNA (rDNA) as matrix-attached DNA loops was examined using a protocol which fractionates chromatin from discrete regions of DNA loops. Southern blot analysis of matrixattached and solubilized chromatin DNA fragments demonstrated that rDNA is associated with the matrix via its 5′ and 3′ nontranscribed spacer sequences (NTS). Although the 45 S rRNA coding sequences were approximately threefold enriched in matrix preparations, the recovery of this DNA (unlike the NTS) was dependent on the extent of nuclease digest and proportional to the length of the matrix-attached DNA fragments. The data suggest that rDNA is organized as matrix-attached DNA loops and only the NTS are directly involved in matrix binding. Further, we demonstrated that while the kinetics and extent of nuclease digestion were similar in all regions of the DNA loops, the nuclease digestion pattern of bulk nuclear and matrix DNA showed a typical nucleosome organization, but the rDNA fragments retained with the nuclear matrix did not.

Molecular characterization of meiotic recombination within the major histocompatibility complex of the mouse: mapping of crossover sites within the I region.

Abstract: The molecular analysis of crossing-over within the mouse major histocompatibility complex provides a useful approach for the study of the structural characteristics of meiotic recombination. In this study five intra-I-region recombinants, each derived fromIk/Ib heterozygotes, were characterized for restriction-fragment length polymorphisms (RFLPs) characteristic of theI region of the two parental strains. Southern blot analysis of intra-I recombinant strains A.TBR2, A.TBR3, A.TBR5, A.TBR13, and A.TBR17 using sixI-region DNA probes revealed that the point of crossing-over in all five recombinants occurred within a 6.2-kbKpnI-EcoRI segment located within theEβ gene. The segments of DNA containing the crossover point from each of the recombinant chromosomes were cloned by screening partial genomic libraries constructed in λgt7 bacteriophage. Construction of partial restriction maps of the cloned segments from the parental and recombinant chromosomes permitted the boundaries of the area containing the crossover site to be narrowed to a 4.0-kb segment located almost entirely within an intron of theEβ gene. The recognition that the points of crossing-over in all five recombinants studied are clustered in a relatively small area of theI region provides further evidence for a hot spot of recombination associated with theEs gene.

Genetic differentiation between laboratory lines of the musk shrew (Suncus murinus, Insectivora) based on restriction endonuclease cleavage patterns of mitochondrial DNA.

Abstract: The cleavage patterns of mitochondrial DNA (mtDNA) by 17 restriction endonucleases were compared between eight lines of musk shrews derived from different wild-caught stocks. Enzymatic digestion by BamHI, PvuII, XbaI, and XhoI showed a cleavage pattern common to all lines that were from five Japanese islands (Nag, Ize, OKI, TKU, and Tr), Bangladesh (BAN), Sri Lanka (SRI), and Java (Bog), and every line lacked cleavage sites for SalI and SmaI. Different cleavage patterns were detected by the remaining 11 enzymes. Within the BAN line, the presence of at least two types of mtDNAs was proved by six enzymes and was not contradictory to the maternal pedigrees going up to the wild ancestors of the stock. More than 30 cleavage sites of the shrew mtDNA were mapped by double-digestion methods. Nucleotide diversities of mtDNA were calculated from these maps and were estimated to be less than 0.5% among Japanese and Bog lines but to be 3.8% between BAN and the other seven lines and 2.3% within the BAN line. These results indicate that BAN shrews differentiate from the other lines to the intersubspecific extent reported in mice previously.

Polymorphism of glycophorins in nonhuman primate erythrocytes

Abstract: Using immunoblotting techniques and polyclonal antisera to human erythrocyte alpha glycophorin, we show that erythrocytes of several species of nonhuman primates, including representatives of anthropoid apes (19 chimpanzees, 3 gorillas, 6 orangutans, and 3 gibbons) and Old World monkeys (3 baboons, 5 rhesus monkeys, and 6 cynomolgus macaques), contain human alpha glycophorin-like molecules. Each species displays a unique glycophorin profile; in anthropoid apes the profile is more complex than in Old World monkeys and more similar to that seen in humans. The chimpanzee was the only species in which human delta-like glycophorin was detected but it differed from its human counterpart in electrophoretic mobility and reaction with M-specific monoclonal antibody. In contrast to humans, highly polymorphic glycophorin profiles were observed in each species of anthropoid apes and three distinct patterns were defined in each. No such polymorphism has been found so far among the Old World monkeys in the limited number of animals studied. The major glycophorins in all species but the chimpanzees failed to react with M- or N-specific monoclonal antibodies, suggesting structural differences from the human within the amino terminal regions. The reaction with the minor glycophorins showed inter- and intraspecies variability. All glycophorins, except delta-like glycophorin in the chimpanzee, reacted with the antiserum to the carboxyl terminal fragment of human alpha glycophorin, indicating a structural relation to the human in this region. An unexpected correlation was observed, in the chimpanzee, between the patterns of electrophoretically resolved glycophorins and the V-A-B-D blood-group phenotypes, allowing the assignment of each determinant to specific glycophorin bands. The basis for the differences observed between human and nonhuman primate glycophorins is not clear but the possibilities include a common nonpolymorphic ancestor and differences in selective pressures.

Historical effective size and the level of genetic diversity in Drosophila melanogaster and Drosophila pseudoobscura

Abstract: We report the results of a sequential gel electrophoretic study of protein variation in Drosophila melanogaster and its comparison with D. pseudoobscura. The number of alleles and mean heterozygosity were lower in D. melanogaster than in D. pseudoobscura. On the other hand, geographical populations of Drosophila melanogaster have been shown to be much more differentiated than those of D. pseudoobscura. The results suggest that in D. melanogaster low-frequency alleles have been lost during the colonization process and that major alleles have become differentiated among populations. Population bottlenecks, due to various causes, appear to have played a significant role in the shaping of genetic variation in natural populations of many species. It is proposed that a comparison of genetic variation at homologous gene loci between related species can bring out effects of historical bottlenecks and provide an alternative approach for analyzing causes of genetic variation in natural populations.

Heterozygosity in inbred strains of the tree-hole mosquitoAedes triseriatus

Abstract: Inbred stocks of the tree-hole mosquitoAedes triseriatus from four localities were developed using full-sib mating. The progress of inbreeding was followed electrophoretically at eight variable and six less variable enzyme loci. Rates of fixation of several of these loci were substantially lower than expected. Discrepancies between observed and expected fixation values were evident in the early stages of inbreeding and became larger as inbreeding progressed.Odh, Hbd, Pgm, andHk-4 were usually not fixed. By the F12 and F14 generations of brother-sister mating, most individuals in the two lines were heterozygotes (Odh andHbd in the TK lines andOdh, Hbd, Pgm, andHk-4 in the TV lines). The probability of maintaining heterozygosity at several selectively neutral and unlinked loci simultaneously is very low.Odh, Hbd, Pgm, andHbd loci are linked to lethal recessives on chromosome 2, creating a balanced lethal system which in turn accounts for the heterozygosity in these inbred mosquitoes.

Biochemical genetics of Es-14 (formerly Es-Si) and a new esterase variation, Es-15, of the laboratory rat (Rattus norvegicus): biochemistry, tissue expression, and linkage to Es-1 in linkage group V.

Abstract: The segregation of rat esterases controlled by loci residing in linkage group V (LGV) has been studied in two backcross series, (LEW/Han × BN/Han)F1 × LEW/Han and (LEW/Han × LE/Han)F1 × LEW/Han. Es-14 (formerly Es-Si) was shown to be closely linked to Es-1. A new esterase locus, Es-15, was described which codes for a liver isozyme. The distribution pattern of three alleles at the Es-15 locus is presented for 52 independent inbred strains. Close linkage of Es-15 to Es-14 and to Es-1 was established, proposing the following gene order: [Es-2, Es-10]—[ES-1, ES-14, ES-15]. The esterase loci on LGV are thus separated into two gene clusters, cluster 1 and cluster 2. These conclusions are supported by the strain distribution patterns of the two RI strain series, LXB and DXE.

Subunit interaction: A molecular basis of heterosis

Abstract: Acid phosphatase, a dimeric enzyme, in Drosophila malerkotliana was studied in isogenic flies to explore the molecular basis of heterosis. As the enzyme activity in heterozygotes is 34% more than that in the better parent (S/S), heterosis is indicated. V max, K m , and K i values are 14.60, 3.6×10−4 m, and 0.45×10−4 m, respectively, for the enzyme from F/S flies and 11.80, 4.0×10−4 m, and 0.37×10−4 m, respectively, for the enzyme from S/S flies. Thus heterosis for enzyme activity results from a better enzyme in F/S flies. The higher efficiency and better quality of the enzyme in F/S flies were traced to the heterodimeric allozyme, present only in heterozygotes. Enzyme activity, V max, K m , and K i values are 0.739, 42.1; 3.6×10−4 m, and 0.50×10−4 m, respectively, for the heterodimeric and 0.513, 36.8; 4.1×10−4 m, and 0.37×10−4 m, respectively, for the better parental homodimeric allozyme. On an equimolar basis the enzyme activity of the heterodimer is 44% higher than that of the better homodimer. The better performance of the heterodimer is probably a reflection of superior conformation resulting from interaction between component subunits (F and S polypeptides).

Macromolecular interaction and the electrophoretic mobility of esterase-5 from Drosophila pseudoobscura

Abstract: Esterase-5 is one of the most polymorphic loci in Drosophila pseudoobscura. Some variants reportedly produce a dimeric enzyme, while a few produce a monomeric form. This paper reports the finding that during electrophoresis ESTERASE-5 exists in a dynamic equilibrium between monomers and dimers, an equilibrium that is dependent on the running temperature of the gels. This is shown by a series of analytical electrophoresis experiments in which the apparent molecular weights of several variants are determined at four different temperatures. Increasing temperatures result in a linear decrease in the logarithm of apparent molecular weights. Macromolecular interactions thus are a significant determinant of EST-5 electrophoretic mobility.

Adh expression in species of the mulleri subgroup of Drosophila.

Abstract: The locus encoding the NAD-dependent alcohol dehydrogenase (alcohol:NAD oxidoreductase; EC 1111) is duplicated in some species of the cactophilicmulleri subgroup ofDrosophila Here we report a survey on the expression throughout development and in different tissues for this system, its regulation using interspecific hybrids, and the effects induced by 2-propanol in 10 species belonging to four different clusters of the abovementioned subgroup Our results indicate different expression throughout development and in different tissues,cis regulation in hybrid ovaries,trans (−) regulation in hybrid adults, and different responses to 2-propanol

Allozyme variation in Anopheles stephensi Liston from Pakistan (Diptera: Culicidae).

Abstract: Allozyme variability was analyzed at 16 loci in 11 lines of Anopheles stephensi Liston from Pakistan. Six lines were considered as samples from natural populations. For these lines the mean number of alleles was 1.31-1.63, the degree of polymorphism was 0.188-0.375, the observed heterozygosity was 0.065-0.086, and the genetic distance ranged from 0.001 to 0.016. No population-specific alleles were found. Interbreeding was considerable (mean Fit = 0.183). Differences in allele frequencies were due considerable (mean Fit = 0.183). Differences in allele frequencies were due primarily to local inbreeding (Fis greater than Fst at most loci). The Lahore line, reared for more than 20 generations, had more homozygotes than the other lines. A line refractory to Plasmodium falciparum and a genetic sexing line exhibited decreased allozyme variability. The latter line showed reduced staining intensity at 10 loci. Linkage studies are recommended for the following loci with rare alleles: Acp, Gapdh, Icd-1, Icd-2, Mpi, and Pgd.

Assignment of the gene for adenine phosphoribosyltransferase on the genetic map of mouse chromosome 8

Abstract: Two electrophoretic variants of adenine phosphoribosyltransferase (APRT) were identified in a population of wild mice (Mus musculus bactrianus). Breeding tests demonstrated that the APRT variants are under the control of two alleles at an autosomal locus designatedAprt. We have examined the linkage relationships betweenAprt and the markers of chromosome 8 including esterase-1 and the centromere. The recombination distance between the centromere andAprt is 44 ± 7 cM, and that betweenEs-1 andAprt is 25 ± 2 cM, i.e., the probable order of the markers examined is cen-Es-1-Aprt on chromosome 8.

Evolutionary relationships between laboratory mice and subspecies of Mus musculus based on the genetic study of pancreatic proteinase loci, Prt-1, Prt-2, Prt-3, and Prt-6.

Abstract: Various patterns of mouse pancreatic proteinase activity bands were observed on agarose gel electrophoresis. Prt-1 a and Prt-1 b genes control the positive (PRT-1A) and negative (PRT-1B) expression of tryptic band V, respectively; Prt-2 a and Prt-2 b correspond to chymotryptic bands II (PRT-2A) and III (PRT-2B); Prt-3 a and Prt-3 b control the low (PRT-3A) and high (PRT-3B) tryptic activities of band IV; the Prt-1 and Prt-3 loci are closely linked on the same chromosome; Prt-6 a and Prt-6 b correspond to tryptic bands I (PRT-6A) and I′ (PRT-6B). Twenty-four laboratory strains from the United States showed the phenotype PRT-1A, PRT-3A, and PRT-2A. Of laboratory strains established in Europe, 6 showed PRT-1A, PRT-3A, and PRT-2A, and 10 had PRT-1B, PRT-3A, and PRT-2A bands. Most wild mice around the world and their descendants showed the phenotype PRT-1B, PRT-3B, and PRT-2A. Only the phenotype of M. m. brevirostris was PRT-1A, PRT-3A, and PRT-2A, which was the same as most laboratory inbred strains. PRT-2B was observed mainly in Japanese (M. m. molossinus) and Korean (M. m. yamashinai) wild mice. PRT-6B was detected only in Mus spicilegus and Mus caroli, but all other mice including wild populations and laboratory strains showed PRT-6A. New biochemical phenotypes such as PRT-2C and PRT-3C were also found in this study.

Localization of the inosine triphosphatase locus (Itp) on chromosome 2 of the mouse.

Abstract: An electrophoretic variant of the enzyme inosine triphosphatase was found by screening inbred strains of mice. Strains with the slower-migrating variant include BALB/cJ, DBA/1J, and PL/J. The Itp locus was mapped between the β-2-microglobulin (B2m) and the agouti (a) loci on chromosome 2. The mapping of Itp on chromosome 2 identifies a chromosomal segment that has been conserved since the divergence of lineages leading to mouse and man.

Characteristics of βA chromosome haplotypes in Japanese

Abstract: DNA polymorphism patterns linked to the βA-globin gene were analyzed in healthy Japanese using four different restriction endonucleases. The chromosomes with the βA-globin gene were mapped through an evaluation of the presence of seven different restriction sites (HincII 5′ to e; HindIII in Gγ and Aγ; HincII in, and 3′ to, ψβ1; AvaII in β; Bam-HI 3′ to β). Among 36 chromosomes analyzed, 20 chromosomes had a haplotype of [+−−−−−+]. Among 55 individuals examined, 7 possessed a homozygous haplotye of [+−−−−−+]. All Japanese with the AγT-globin gene had a subhaplotype of [−++−+] 5′ to the δ-globin gene. Their major haplotypes were [−++−+−+] and [−++−++−]. It was expected that the presence of the AγT-globin gene in Japanese may be deduced from subhaplotypes 5′ to the δ-globin gene.