bluuebunny/crossref_metadata_2025_split huggingface dataset:
The distribution of heterozygosity in temperate and tropical species ofDrosophila
Authors: Latter B. D. H. 
Published: September 2009

SUMMARYElectrophoretic surveys for nine species ofDrosophilahave been summarized in terms of the relative contribution to heterozygosity of each of ten gene frequency classes, the mean frequency of heterozygotes within subpopulations, and the degree of genetic divergence between subpopulations. It has been shown that the neutral model proposed by Kimura, and modified by Ohta to include the accumulation of slightly disadvantageous mutations, is capable of explaining all features of the data. The consistent difference between group I and group II enzymes can be explained by a difference in the average intensity of selection against mutational variants in the two groups. A highly significant difference between the temperate and tropical species in the distribution of heterozygosity appears to be due to the smaller effective breeding population sizes in the case of the temperate species.
Multilocus nonrandom associations inDrosophila melanogaster
Authors: Malpica J. M. , Briscoe D. A. 
Published: September 2009

SummarySeven third chromosome samples from laboratory populations and one from a wild population were classified by their genotypes at five allozyme loci and by the occurrence of lethals. The data were analysed for independence among classifications by a randomization method, and it was found that when the number of classifications is high the independence hypothesis does not hold. We have split the independence hypothesis among populations and have found that the lack of fit to the hypothesis comes mainly from the wild population. As one of our classifications was lethality, these findings seriously question the interpretation of multilocus fitness estimations. To split the independence hypothesis into interactions, the criterion of Bartlett for non-interaction with exact probability methods was used; interactions at the levels of pairs and triplets were not significant as a whole. It was not possible to carry the interaction analysis any further as the frequencies of chromosomal types were completely determined by their marginal totals at orders of interaction higher than that of triplets. Available parametric estimations of these high order interactions are therefore of dubious meaning. The analyses of chromosome samples and the temporal surveys of population cages described here, as well as data from the literature, suggest that the Est 6-Pgm region is prone to show disequilibrium.
Lethality of heterozygotes betweent-haplotype complementation groups of mouse: sex-related effect on lethality oft6/tw5heterozygotes
Authors: Bechtol Kathleen B. 
Published: September 2009

SummaryThe various lethalt-haplotypes are divided into several complementation groups defined by lethality oftx/tyheterozygotes, and only partial complementation is usually observed in heterozygotes betweentcomplementation groups. Several effects of thetregion have been found to be preferentially or exclusively detectable in males. This paper describes results showing that the viability oft6/tw5heterozygotes is influenced by the sex of the embryo; female viability is only slightly reduced (viability ratio approximately 0·80), while male viability is far below normal (0·25).
Identification of the chromosomes involved in a wheat-rye translocation using isozyme markers
Authors: Rao I. Narayana , Rao M. V. Prabhakara 
Published: September 2009

SummaryMonosomic and disomic substitutions of Imperial rye chromosome C for 4A of Chinese Spring wheat were analysed for two enzyme markers, alcohol dehydrogenase (ADH) and 6-phosphogluconate dehydrogenase (6-PGD). The gene(s) coding for ADH and 6-PGD were located on the short and long arms of rye chromosome C respectively.Isozyme analyses revealed that the substitute chromosome was a translocation involving alpha arm of wheat chromosome 4A and long arm of rye chromosome C. Pairing behaviour of the substitute chromosome with rye and wheat chromosomes in hybrids with rye addition line C and ditelosomic 4A (alpha) confirmed this.
The structure of hair and follicles of mice carrying the naked (N) gene
Authors: Raphael Kathryn A. , Chapman R. E. , Frith Penelope A. , Pennycuik Pamela R. 
Published: September 2009

SummaryThe hairs and follicles from mice carrying the naked (N) gene have been examined using both scanning and transmission electron microscopy in addition to light microscopy. Fibre cuticle cells and occasionally cortical cells were absent from the follicles of N / + mice when the base of the hair was growing. In N / N follicles there was a frequent lack of both cuticle and cortical cells throughout the growth phase of the follicles. Abnormalities were also observed in the manner in which the synthesized keratin was deposited in the fibres. The possible mode of action of the N gene is discussed in the light of these results.
Genetics of the lac-PTS system ofKlebsiella
Authors: Hall Barry G. , Imai Ko , Romano Charles P. 
Published: September 2009

SummaryThe isolation of a temperature sensitivepts Imutant which fails to utilize lactose provides strong evidence thatKlebsiellastrain CT-1 utilizes lactose via a phosphoenolpyruvate dependent lactose-phosphotransferase system (PTS-lac). We designate this lactose utilization systemeluforevolved lactose utilization. Analysis of a series ofLac−mutants identifies two genes,eluAandeluB, whose function is required for lactose utilization by this pathway. The functions specified by these genes are not known, but neither locus specifies the hydrolytic enzyme phospho-β-galactosidase. A mutant of CT-1, strain RPD-2, exhibits a half-maximal growth rate at a lactose concentration 40 fold lower than that of strain CT-1; and it has aKmfor lactose uptake that is 40 fold lower than that of strain CT-1. That mutation defines the locuseluC, which is assumed to specify the enzyme Il(lac) of the PTS-lactose system. From the observations that (i) cellobiose induces the phospho-β-galactosidase enzyme, (ii) pregrowth in cellobiose dramatically reduces the growth lag when cells are shifted into lactose minimal medium, (iii)eluBmutants exhibit a growth lag when shifted into cellobiose minimal medium, and (iv) lactose induces a phospho-β-glucosidase enzyme; we speculate that the phospho-β-glucosidase enzyme is the same enzyme as the phospho-β-glucosidase that normally functions in cellobiose metabolism. We conclude that the original mutation that allowed CT-1 to utilize lactose was a regulatory mutation that permitted inducible expression of theeluCgene.
X-chromosome activity in female mouse embryos heterozygous forPgk-1and Searle's translocation, T(X; 16) 16H
Authors: McMahon A. , Monk M. 
Published: September 2009

SUMMARYTo investigate whether the preferential expression of genes on the translocatedXchromosome in female mice carrying theX-autosome translocation T(X; 16)16H (Searle's translocation) is due to non-random inactivation or to cell selection, we examined tissues of mouse embryos heterozygous for the X-linked gene coding for phosphoglycerate kinase (Pgk-1). From the cross T16HPgk-lb/+Pgk-lb♀ × +Pgk-la/Y♂, embryos expressing both isozymic forms of PGK-1 in the epiblast, and only the maternally inheritedPgk-lballele in extra-embryonic tissues, were assumed to be chromosomally balanced, heterozygous female embryos carrying the Searle's translocation (like the mother). The normalXchromosome in this cross carries a high-expressionXceclocus. At 6 days post-coitum (p.c.) both isozymes were equally expressed in the epiblast as expected if bothXchromosomes are active, but by 7 days p.c. the PGK-1B contribution was significantly less than 50%, suggesting thatXinactivation has occurred with a bias towards inactivation of the translocatedXchromosome carrying the lower-expressionXceallele. By 8 days p.c. the situation was the reverse, with aPgk-lbcontribution of significantly more than 50%, and by 12½ days p.c. noPgk-laexpression could be detected. We interpret the dramatic change in isozy me expression between 7 and 8 days p.c. as indicating rapid selection against cells that had inactivated the translocated 16Xchromosome. Two 7-day p.c. embryos unexpectedly showed equal expression of bothPgk-1alleles in both embryonic and extra-embryonic tissues; these were presumably chromosomally unbalanced embryos which had inherited from the mother both an active translocated 16Xchromosome carryingPgk-lband an active normalXchromosome carryingPgk-la.
Post-settlement viability in the American oyster (Crassostrea virginica): an overdominant phenotype
Authors: Zouros E. , Singh Shiva M. , Foltz David W. , Mallet André L. 
Published: September 2009

SUMMARYThe degree of heterozygosity as determined by electrophoretic analysis of three or four polymorphic loci correlates positively with survival in age groups of the American oyster (Crassostrea virginica) collected as spat from two different natural populations. The phenomenon is shown to operate in ages from 2 weeks (post-settlement) to 3 years and appears to be general in populations of marine molluscs. The most likely explanation for this result is that heterozygosity improves survival through its effect on growth (heterozygotes grow faster). The effects of individual loci on viability are independent of each other. A direct involvement of the enzyme polymorphisms is the most probable genetic interpretation of the data, but associative overdominance cannot be excluded.
Cytological location and lethal interactions of three Minute loci in chromosome 3 ofDrosophila melanogaster
Authors: del Prado Jaime Moscoso , Ripoll Pedro 
Published: September 2009

SUMMARYUsing seven newly induced duplications, three Minute loci have been located cytologically:M(3)hS 37in 65F10–11; 66A (a new Minute locus),M(3)iin 67C, andM(3)hyin 68F; 69F.M(3)hS 37andM(3)hywere previously thought to be allelic because they do not complement for lethality. The finding of Minute mutations with additive or synergistic rather than epistatic interactions makes us suspect that some other Minute mutations have been erroneously called allelic. The involvement of Minute loci in more than one biochemical pathway is discussed in view of the existence of synergistic interactions and of Minute loci without known mutant alleles.
Genetic variation in β-adrenergic receptors in mice: A magnesium effect determined by a single gene
Authors: Markovac Jasna , Erickson Robert P. 
Published: September 2009

SUMMARYGenetic variation in the amount of binding of dihydroalprenolol (a potent antagonist) to hepatocyte β-adrenergic receptors has been observed among inbred strains of mice. This variation is attributed to a differential effect of magnesium on the receptors between the high and low binding strains. Evidence for a single gene controlling the magnesium effect on dihydroalprenolol binding to β-adrenergic receptors was found using recombinant inbred lines between the high and low strains. We suggest the provisional gene symbolBadm.
Quantitative genetic variation in the skeleton of the mouse: I. Variation between inbred strains
Authors: Lovell D. P. , Johnson F. M. 
Published: September 2009

SUMMARYA series of six bones from samples of mice from eleven inbred strains and one F1hybrid were measured using a simple apparatus. The bones examined were the mandible, os coxae, femur, tibia–fibula, scapula and humerus. Considerable variation in the shape of each bone was found and successful discrimination between the strains was obtained. Correct strain classification ranged from 87% for the scapula to 98% for the os coxae. Gross abnormalities and quantitative variants were identified.As the pattern of discrimination is different for each bone, the use of other bones in addition to the mandible may improve resolution in the identification and quality control of mouse stocks. The objective and precise identification of abnormal and variant bones suggests that the method may be useful for population studies and for the detection of induced skeletal abnormalities in toxicological investigations.
The genetic control of hexokinase isozymes in wheat
Authors: Ainsworth C. C. 
Published: September 2009

SUMMARYIn extracts of mature wheat grains, 13 hexokinase isozymes were distinguished by IEF. The genes controlling the production of five isozymes were located on chromosome arms 1BS, 1DS and 3BS by nullisomic analysis. The three loci, part of two homoeoallelic series (Hk-1andHk-2) are designatedHk-B1,Hk-D1andHk-B2respectively. Analysis of chromosome 1D short-arm terminal deletions indicated theHk-D1locus to be located proximally to the glucose phosphate isomerase locus,Gpi-D1on the shortarm. Three variant HK phenotypes were distinguished amongst 55 hexaploid wheats examined. Analysis of seven Chinese Spring/Agropyron elongatumchromosome addition lines showed thatAg. elongatumisozymes were expressed in the wheat background in additions IV and V.
Clear plaque mutation sites linked to theimmIregion of the Salmonella phage P22
Authors: Prell Hermann H. , Auer Johanna M. , Soška Jiri 
Published: September 2009

SUMMARYA complete genetic map has been established for the P22 clear plaque forming mutationscir4-l,cir5-l andcir6-l. These are located within or closely linked to theimmIregion of P22 and represent a new class of clear plaque forming mutants located outside and rather distant from the immC region. They were mapped with respect to the markersmnt, vyand ant of theimmIregion and to genes16and9which span it. The threecirmutations complement each other and – with one possible exception – thecl,c2andc3mutations of theimmCregion. P22cir6-l – like P22cir5-l (Harveyet al.1981) – is suppressed by theant−am19 allele, whereas P22cir4-l is not. The results are discussed in terms of the regulation of earlyantexpression.
Daughterless X Sxr/Y Sxr mice
Authors: McLaren Anne , Burgoyne Paul S. 
Published: September 2009

SUMMARYMcLaren & Monk (1982) and Cattanach et al. (1982) reported that T(X; 16)16H/X Sxr mice, in which the X chromosome bearing Sxr is the inactivated X chromosome, can develop as fertile females. By mating such females to X/Y Sxr males it has been possible to produce mice homozygous for Sxr. Two X Sxr / Y Sxr males were identified which together fathered 141 sons and 1 daughter. The single daughter proved to be XO, indicating a non-disjunctional event with neither paternal sex chromosome being transmitted. It is concluded that X Sxr / Y Sxr mice are viable and fertile, and that all their progeny, provided they receive a paternal sex chromosome, develop as males.
Activity differences between acid phosphatase allozyme variants ofDrosophila virilis: Differences in intracellular localization of allozymes
Authors: Narise Sumiko 
Published: September 2009

SummaryThree acid phosphatase allozyme strains (Acph-1, Acph-2 and Acph-4) ofDrosophila virilisshow large differences of enzyme activity when examined by means of starch gel electrophoretic technique, Acph-4 strain showing approximately four times the activity of Acph-1 and twice that of Acph-2, as reported previously (Narise, 1976). Crude extract difference between Acph-4 and Acph-1 strains is less than twofold and this compared with larger differences in supernatants. Cell fractionation and density gradient centrifugation demonstrated that the acid phosphatase resides mainly in lysosomes and becomes soluble in part during preparation without structural damage to lysosomes. The solubility of the allozymes from lysosomes was variable among the three strains. ACPH4allozyme was released in the highest degree. However, the release-rate of other lyso-somalenzymes, such as α-glucosidase, β-galactosidase and β-glucuronidase was similar among these strains. These results suggest that the strain variation in ability of the allozymes to be incorporated into lysosomes is due to the allozymes themselves, not due to alteration in the lysosomes.
The genetics of hormone-induced cyclic AMP production and PhospholipidN-methylation in inbred strains of mice
Authors: Markovac Jasna , Erickson Robert P. 
Published: September 2009

SummaryGenetic variation in hormone-sensitive cyclic AMP production was investigated among inbred strains of mice. Significant strain differences were observed in β-adrenergic- and glucagon-stimulated adenylate cyclase activity. Comparable differences were also found in membrane methyl-transferase I activity in these strains. Our results of studies using F1progeny of high and low strains suggest a dominance of high MT I activity over low MT I activity. Investigation of recombinant inbred lines between the high and low strains indicates that MT I activity is regulated by at least two major genes;H-2-congenic lines of several inbred strains were then used to identify an association between hormone-stimulated MT I activity and the mouse major histocompatibility complex.
Genome organization of thePseudomonas aeruginosanarrow host range plasmid R91–5 determined by deletion and cloning analysis
Authors: Moore R. J. , Krishnapillai V. 
Published: September 2009

SummaryBy physical and genetic analysis of deletion mutants of the narrow host range IncP-10P. aeruginosaconjugative plasmid R91–5 it has been shown that the phenotypes related to its transfer, namely the inhibition of the replication of the phage G101, entry exclusion and the fertility inhibition of the wide host range plasmid R18 map at kilobase coordinates 19·7–20·7, 18·5–19·7, 28·8–30·15 and/or 34·9–36·15, respectively. These locations have been confirmed by cloning restriction enzyme generated DNA fragments of R91–5 into a small broad host range, multicopy non-conjugative plasmid.
Observed relationships between protein heterozygosity and protein genetic distance and comparisons with neutral expectations
Authors: Ward R. D. , Skibinski D. O. F. 
Published: September 2009

SummaryRelationships between protein genetic distance (D) and protein heterozygosity (H) were studied using allele frequency data for 42 proteins derived from multilocus electrophoretic surveys of genetic variation in over 200 invertebrate and over 300 vertebrate species.D¯andH¯values for the different proteins (mostly enzymes) were calculated, and large and significant correlations betweenD¯andH¯were found in comparisons of both intraspecific and interspecific populations. Empirical relationships betweenD¯andH¯were compared with neutral expectations under the stepwise model of neutral mutation with the assumption that populations are in equilibrium with respect to the effects of mutation and genetic drift.At low divergence levels, a linear relationship ofD¯onH¯was observed, but at high levels of divergenceDtended towards an asymptote at highH¯. The results at high divergence cannot be explained using the approximate relationshipD=2ut(whereu= mutation rate,t= time). However, computer simulations of neutral models showed that changes of this nature in the relationship betweenD¯andH¯were to be expected as divergence increases, the equationD=2utbeing a poor approximation at highDWe therefore conclude that the observed relationships betweenD¯andH¯are, in fact, compatible with equilibrium neutral theory.
A gamma ray-induced non-excitable membrane mutant inParamecium caudatum: a behavioral and genetic analysis
Authors: Takahashi Mihoko , Haga Nobuyuki , Hennessey Todd , Hinrichsen Robert D. , Hara Ritsuo 
Published: September 2009

SUMMARYA new CNR (caudatumnon-reversal) mutant ofParamecium caudatumwas isolated after gamma ray mutagenesis. This CNR lacks not only the transient inward Ca2+current but also the sustained Ca2+current. It was shown to complement the three known CNR mutants ofP. caudatum(cnrA, cnrBandcnrC) by crossbreeding analyses. Thus, this new mutant belongs to a 4th CNR locus, designatedcnrD. The defect ofcnrDcan be partially rescued by microinjection of cytoplasm from any of the three CNR mutants or the three Pawns (pwA, pwBandpwC) inP. tetraurelia. Since the three CNR genes have been shown to be different from the three Pawn genes by cytoplasmic complementation test (Hagaet al.1983), this result suggests thatcnrDis the 7th non-excitable mutant inParamecium. Thus, there are at least seven genes controlling Ca2+channel function inParamecium.
Male mating success and fertility inDrosophila melanogaster
Authors: Partridge Linda , Mackay Trudy F. C. , Aitken Susan 
Published: September 2009

SUMMARYThe male mating ability and male fertility of 40 third chromosome homozygote lines has been measured. There was significant between-line differentiation for both characters, and comparison with a heterozygous stock indicated inbreeding depression and hence dominance variation for them. The characters showed significant positive correlation both with each other and with other fitness components and total fitness, as measured by Mackay (1985). This pattern of large positive correlations between fitness components is not expected to occur in outbred populations.
Chromosome differences between substrains of the inbred 101 mouse strain
Authors: Evans E. P. , Burtenshaw M. D. , Adler Ilse-Dore 
Published: September 2009

SUMMARYA centromeric heterochromatin (Hc) comparison of two substrains of the mouse inbred strain 101 with another two, revealed differences in at least two and possibly in up to six chromosome pairs. The differences could have arisen by the inclusion of chromosomes from the inbred strain C3H/He.
Structural genes for phosphatases inAspergillus nidulans
Authors: Caddick Mark X. , Arst Herbert N. 
Published: September 2009

SUMMARYAlthough the fungusAspergillus nidulanshas a multiplicity of phosphatases and of genes where mutations affect one or more phosphatases, we have succeeded in identifying structural genes for three phosphatases as well as one other gene which might encode a fourth. Using both conditional and non-conditional mutations,palD has been shown to be the structural gene for a phosphate-repressible alkaline phosphatase,palG to be the structural gene for a non-repressible alkaline phosphatase which apparently exists in two electrophoretically distinct forms (but whose rates of thermal inactivation are apparently very similar) andpacA to be the structural gene for both intracellular and secreted forms of a phosphate-repressible acid phosphatase. Colony staining techniques for the enzymes specified bypalD andpacA have been described previously but we have now shown that the enzyme specified bypalG can be detected by staining toluene-permeabilized colonies. Mutations inpacG lead to loss of non-repressible acid phosphatase as judged by colony staining and electrophoretic patterns but their effects on assays of activity in cell-free extracts are only marginal. Under phosphate-limited, but not phosphate-starved or phosphate-sufficient, conditions,pacG−mutations also affect the regulation of other, phosphate-repressible phosphatases. None of these phosphatases, alone or in combination, plays an essential role.
Two-dimensional Gel Analysis of Proteins from Mouse Fetuses with Trisomy 19 after DEAE-Sepharose Chromatography
Authors: Reichert Gerd H. 
Published: September 2009

SummaryIsoelectrofocusing two-dimensional polyacrylamide gel electrophoresis (IEF-2D-PAGE) offers the opportunity to detect typical alterations in the protein pattern of trisomic mouse foetuses at a given time of development. The fractionation of the cell lysate by differential centrifugation into various subcellular components (nuclei, membranes, polyribosomes, cytoplasmic proteins) and fractionation of the proteins through DEAE-Sepharose chromatography allows detection of protein differences.It is possible to detect eight differences in the protein patterns between trisomy 19 (Ts 19) mouse foetuses and euploid mouse fetuses at day 15. Five of these differences are quantitative in nature, three are qualitative. One of these proteins is synthesized in Ts 19 foetuses at a higher level than in euploid mouse fetuses (primary gene dosage effect). The other seven proteins are reduced or not present in trisomic foetuses (consequences of primary gene dosage effects).The molecular mass of the individual proteins ranges from 13 to 41 kDa.