bluuebunny/crossref_metadata_2025_split huggingface dataset:
The maintenance of polygenic variation through a balance between mutation and stabilizing selection
Authors: Barton N. H. 
Published: September 2009

SummaryThe maintenance of polygenic variation through a balance between mutation and stabilizing selection can be approximated in two ways. In the ‘Gaussian’ approximation, a normal distribution of allelic effects is assumed at each locus. In the ‘House of Cards’ approximation, the effect of new mutations is assumed to be large compared with the spread of the existing distribution. These approximations were developed to describe models where alleles may have a continuous range of effects. However, previous analyses of models with only two alleles have predicted an equilibrium variance equal to that given by the ‘House of Cards’ approximation. These analyses of biallelic models have assumed that, at equilibrium, the population mean is at the optimum. Here, it is shown that many stable equilibria may coexist, each giving a slight deviation from the optimum. Though the variance is given by the ‘House of Cards’ approximation when the mean is at the optimum, it increases towards a value of the same order as that given by the ‘Gaussian’ approximation when the mean deviates from the optimum. Thus, the equilibrium variance cannot be predicted by any simple model, but depends on the previous history of the population.
Inheritance of protein amounts: comparison of two-dimensional electrophoresis patterns of leaf sheaths of two maize lines (Zea maysL.) and their hybrids
Authors: Leonardi A. , Damerval C. , de Vienne D. 
Published: September 2009

SummaryDenatured total proteins of two maize lines and their reciprocal F1hybrids were analysed by two-dimensional electrophoresis. Quantitative (spot more or less intense) and qualitative (presence or absence of spots) differences exist between the lines, and correspond to 11% of the total reproducible spots. Non-additive effects on spot intensities were found in the hybrids, which display spots similar to the more intense parental spot for 11% of varying spots. This may correspond todominance for regulatory systemscontrolling the protein amounts. Such interactions contrast with additivity classically described for enzymes or DNA.
Differences in or near the responder region of complete and partial mouset-haplotypes
Authors: Lyon Mary F. , Zenthon Joanna 
Published: September 2009

SummaryThe transmission ratio distortion seen in males heterozygous for a mouset-complex has been explained on the basis of trans-acting distorter genes, having a harmful effect on a responder gene. Thet-complex form of the responder is relatively resistant to these harmful effects and hence is preferentially transmitted. Animals homozygous for thet-complex responder would be expected to show equal transmission of the two homologous chromosomes, but this is not always so. Studies described in this paper have shown differences among completet's in their transmission when opposite a constant responder carrying partialt-haplotype. In addition, the proximal partial haplotypesth49andtw18, both derived fromtw5but of different lengths, behave differently when opposite a responder. The three central partial haplotypes,tlowH,tlow2Handtlow3H, also differ, in thattlow3Hshows lower transmission thantlowHortloW2Hwhen opposite either wild-type, or another responder, or distorter genes. These results can be explained either on the basis of differences in the responder region of various haplotypes, including the possibility of varying numbers of copies of the relevant sequences, or on the basis of differences in cis-acting (as opposed to trans-acting) distorter genes.
The probability of establishment of an advantageous mutant in a subdivided population
Authors: Barton N. H. 
Published: September 2009

SummaryA method is developed for calculating the probability of establishment of an allele which is favoured in some places, but not others, in a large subdivided population. This method is quite general, and could be used to calculate the chance that any system which is linear near an absorbing boundary will move away from that boundary. The results are applied to a population distributed along one dimension. Only mutants which arise within a distance ∼ σ/ √2s of the region in which they are favoured stand an appreciable chance of establishment. The net chance of establishment of mutations distributed randomly across the habitat will be decreased by gene flow if selection against them is sufficiently strong. However, if the mutations are only weakly deleterious outside some limited region, gene flow may increase the net chance of establishment.
Quantitative variation and chromosomal location of satellite DNAs
Authors: Stephan Wolfgang 
Published: September 2009

SummaryA model of the evolutionary accumulation of highly repeated DNA (HRDNA) is proposed. The accumulation of HRDNA sequences, which are organized largely in tandem arrays and whose functional significance is obscure, is explained here as a consequence of the action of the forces of amplification (promoting increase in copy numbers) and unequal crossing over, random drift and natural selection (controlling copy numbers). This model provides a general framework (i) to study the chromosomal location of satellite DNAs present in the genomes of all higher eukaryotes, and (ii) to explain the significant variation in the amounts of satellites which is frequently found among closely related species, but only rarely within a species. A review of the relevant data is included and open questions are identified.
Sterility-mutability correlation: On the correlation between sterility and mutability during P-M hybrid dysgenesis inDrosophila melanogaster
Authors: Simmons Gail M. 
Published: September 2009

SummaryTwelve isogenicXchromosome lines from a single natural population ofDrosophila melanogasterwere tested for their potential to induce gonadal dysgenesis andsinged-weakmutability inP-Mhybrid dysgenesis. The correlation between sterility and mutability was significantly positive for Cross A, confirming the results reported by Engels (1984) and Kocur, Drier & Simmons (1986). In Cross A* cytotype tests, however, two of the lines gave strikingly different results when measured by the gonadal dysgenesis test as compared to thesinged-weaktest. Positive correlations between traits within a given line were generally not observed. The results suggest that the relationship between gonadal dysgenesis production and the mobilization ofPelements insinged-weakmutability is more complicated than that proposed by Engels (1984). The two phenomena may be separable under certain conditions. Neither test can be taken as an adequate characterization of the hybrid dysgenesis ‘profile’ of a line of flies.
Erratum
Authors: Nadeau Joseph H. 
Published: September 2009

Genet. Res., Camb. (1986), 48, pp. 175–178A chromosomal segment conserved since divergence of lineages leading to man and mouse: the gene order of aminoacylase-1, transferrin and beta-galactosidase on mouse chromosome 9In the summary on page 175 and in the last paragraph on page 176, the second aminoacylase locus, Acy-2, was inadvertently described as requiring MgC12. The correct compound is MnC12.
Heterospecific transcription of theEscherichia coli rpoB-3 allele in Gram-negative bacteria
Authors: Al-Doori Zainab 
Published: September 2009

SummaryrpoB is the structural gene for the β-subunit ofE. coliRNA polymerase. TherpoB-3 allele confers resistance to the antibiotic rifampicin and is unusual in being dominant to the wild-type allele. We used the plasmid pZD23, a derivative of the broad host range conjugative plasmid RP4, to introduce therpoB-3 allele into a range of bacterial species. Species belonging to the same family asE. coli(Enterobacter aerogenes, Citrobacter freundii, Hafnia alvei møller, Klebsiella pneumoniae, Salmonella typhimurium) expressedrpoB-3 to give a rifampicin resistant phenotype; this demonstrated heterospecific transcription. The transfer of pZD23 to the non-Enterobacteriaceae speciesAzotobacter vinelandiiandRhizobium leguminosarumdid not result in rifampicin resistance. In the former case this was due to non-expression of therpoB-3 resistance phenotype, in the latter case the dominant resistance phenotype had been lost from pZD23. Heterospecific transcription can be used as a criterion for the investigation of genetic relatedness between bacterial species.
Genetic and developmental analysis of the sex-determining gene ‘double sex’ (dsx) ofDrosophila melanogaster
Authors: Nöthiger Rolf , Leuthold Margrit , Andersen Nils , Gerschwiler Pia , Grüter Armin , Keller Walther , Leist Christian , Roost Maja , Schmid Helen 
Published: September 2009

SummarySex determination inDrosophiladepends on the ratio ofXchromosomes to sets of autosomes (X:A). This chromosomal signal is used to regulate a few control genes whose state of activity selects either the male or the female sexual pathway. We have studied the structure and function ofdsx(double sex) which appears to be the last regulatory gene on whose function the sexual pathway eventually depends. We have mutagenized the locus, varied the doses of dominantdsx-mutations and wildtype alleles, and combined differentdsx-alleles with recessive mutations in other sex-determining genes, such asix,tra-2andtra.The locusdsxharbours two genetic functions,dsxmto implement the male program,dsxfto implement the female program. We found thatdsxmanddsxfcan mutate independently although most mutations abolish both functions. We conclude thatdsxmanddsxfeach have their specific domain, but also share a large region of DNA that is essential for both functions. We present evidence that the dominant mutations correspond to a constitutive expression of the male-determining functiondsxm, with the simultaneous abolishment of the female-determining functiondsxf. This effect can be counteracted by two doses of expresseddsxfso that a female phenotype results. The products of one dose of expresseddsxmand one dose of expresseddsxfin the same cell appear to neutralize each other which leads to a null phenotype. The mutant combinations suggest that the product ofdsxfrequires the products ofix+,tra-2+andtra+to become functional.
Erratum
Authors: Boussy Ian A. 
Published: September 2009

Genet. Res., Camb. (1987), 49, pp. 11–18A latitudinal cline in P–M gonadal dysgenesis potential in Australian Drosophila melanogaster populationsFigures 1 and 2 have been interchanged with their legends. Thus the maps shown as Fig. 2 belong to the legend of Fing. 1, and should be labelled Fig. 1, and vice versa.
Biochemical phylogeny of the eight species in the Drosophila melanogaster subgroup, including D. sechellia and D. orena
Authors: Cariou Marie Louise 
Published: September 2009

SummaryThe phylogenetic relationships of the eight species of the Drosophila melanogaster subgroup are examined on the basis of genetic variation at 33 putative enzyme loci. Values of Nei's genetic distance (ds) range from 0·28 to 1·74. D. sechellia appears closer to D. simulans than to D. mauritiana, the two former being the most closely related. D. orena is quite distantly related to D. erecta (ds = 1). Genetic differentiation supports the existence of three main lineages within the melanogaster subgroup and the yakuba-teissieri pair appears to be closer to the melanogaster lineage than to the erecta-orena one. Inferences of the times of species divergence from allozyme data are made and their agreement to other estimates is discussed.
Linkage disequilibrium in experimental populations ofDrosophila simulans: a test of the random drift hypothesis
Authors: Montchamp-Moreau Catherine , Katz Mariano 
Published: September 2009

SummaryLinkage disequilibrium between five polymorphic enzymic loci of the third chromosome (Esterase-6, Phosphoglucomutase, Esterase-C, Aldehyde Oxidase and Acid Phosphatase) was studied in experimental populations ofDrosophila simulans. Gametic data were obtained by mating sampled males with homozygous females at the five loci. Four cage populations were initiated with flies caught from natural populations. Extensive linkage disequilibrium was detected after 25 or 34 generations. The effective size of these populations was estimated about 400. Monte-Carlo simulations were performed in order to determine whether the observed disequilibria could be due to genetic drift. The observed probability distribution of the experimental values ofr(the gametic correlation coefficient) was consistent with the distribution expected under random genetic drift. Our results are thus in accordance with the neutralist hypothesis.
TheMus musculus musculustypeYchromosome predominates in Asian house mice
Authors: Nishioka Yutaka , Lamothe Estelle 
Published: September 2009

SummaryUsing a mouseYchromosomal repetitive sequence that differentiates between theMus musculus musculustypeYchromosome and theM. m. domesticustypeYchromosome, we studied theYchromosome inM. m. molossinus, M. m. castaneusandM. m.subspecies specimens recently trapped in Japan, Taiwan and China as well as Asian mice maintained at the Jackson Laboratory and Litton Bionetics. Here we report that theM. m. musculustypeYchromosome predominates in Asian house mice and that Japanese mice maintained at some laboratories may not represent typicalM. m. molossinus.
Hybrids show parental influence in the adaptation of wild house mice to cold
Authors: Barnett S. A. , Dickson R. G. 
Published: September 2009

SummaryWild house mice, Mus musculus, were bred (a) at 3 °C (‘Eskimo’) and (b) at 23 °C. Mice of the ninth generation bred at 23°C were transferred to the cold environment. Their young, and Eskimo of the same (tenth) generation, were mated to give the four possible types of pairs: controls; the two reciprocal hybrid pairings; and Eskimo. In the resulting (eleventh) generation there were therefore two hybrid classes, genetically identical but with different parentage. The growth and reproduction of the eleventh generation were studied. At all ages from birth, mice with Eskimo mothers were heavier than those with control mothers. They were also better breeders: (1) they matured earlier; (2) their litters were larger; (3) the mortality of their young in the nest was lower. In one feature there was heterosis: of the four classes, the hybrids with Eskimo mothers produced the largest litters. These and previous findings suggest rapid selection, in the cold, for changes in growth, reproductive physiology and other aspects of metabolism. The cold-adapted mice of a given generation differed from the controls partly as a result of favourable parental effects, which acted in conjunction with genetical differences. It is hypothesized that the ecological versatility of Mus musculus depends partly on the presence, in each population, of alternative genotypes which allow rapid adaptation to new conditions.
Y-chromosomal and other factors in the development of testis size in mice
Authors: Hunt Suzan E. , Mittwoch Ursula 
Published: September 2009

SummaryTestis size was investigated in two inbred strains of mice, BALB/c/Ola and CBA/Gr, at different ages. BALB/c mice were found to have the larger testes from day 14 of embryonic development onwards. Body weights of the two strains differed to a lesser extent. The differences in testis weights were analysed post-natally at 2, 4, 6 and 8 weeks in the two strains, F1s, F2s and backcrosses. Testis size was found to be affected by the origin of the Y chromosome, the X chromosome, the autosomes (and/or pseudoautosomal regions) and by maternal factors. At 8 weeks of age, the Y-chromosomal effect was at its strongest, and the X-chromosomal effect was at its weakest, while the maternal effect had vanished. It is postulated that non-Y-chromosomal factors which modify testis size may affect the gonads in both sexes. The possibility is discussed that loci affecting gonad size may be identical with testis-determining factors.
Mouse testicular protein variants, including tubulin, detected by isoelectrofocusing two-dimensional gel electrophoresis
Authors: Schneider J. , Erickson R. P. , Hanash S. 
Published: September 2009

SummaryWe have utilized isoelectrofocusing two-dimensional polyacrylamide gel electrophoresis (IEF-ID-PAGE) to determine the frequency of variant proteins detected in mouse testes, and to examine an inbred strain with spermatogenic abnormalities. The observed frequency of variants, 4·2 ± 1·0%, is comparable to results reported for liver. A variant for a protein, identified as tubulin by immunoblotting, was observed in an inbred strain (PL/J) which has defective spermatogenesis, but was also observed in another inbred strain without spermatogenic defects. The gene symbolTbnis proposed for this β-tubulin locus.
A new gene controlling sulphite reductase inAspergillus nidulans
Authors: Nadolska-Lutyk Janina , Paszewski Andrzej 
Published: September 2009

SummaryA new gene designatedsGwas identified inAspergillus nidulansby mutation affecting the enzyme sulphite reductase and leading to a strong derepression of arylsulphatase and enzymes constituting the alternative pathway of cysteine synthesis. The results indicate that proper physiological functioning of this pathway is strongly dependent on full activity of the sulphate assimilation pathway.
Mapping and biochemical analysis ofHor 4 (Hrd G), a second locus encoding B hordein seed proteins in barley (Hordeum vulgareL.)
Authors: Shewry Peter R. , Parmar Saroj , Franklin Julian , White Rodger 
Published: September 2009

SummaryThe hordein polypeptide controlled by theHrd G (Hor 4)locus in Elgina and derived lines was purified by preparative isoelectric focusing. The amino acid composition was similar to those of the major B hordeins encoded by theHor 2locus. Genetic analysis confirmed thatHor 4is located proximally toHor 1on the short arm of chromosome 5. It is speculated thatHor 4arose by translocation of genes fromHor 2, possibly in an ancestor of Elgina.
Identification of a second locus encoding β-amylase on chromosome 2 of barley
Authors: Kreis M. , Williamson M. S. , Shewry P. R. , Sharp P. , Gale M. 
Published: September 2009

SummaryA barley endosperm cDNA clone was used to study the polymorphism and chromosomal location of β-amylase genes in barley. Analysis of DNA from seven cultivars digested with three restriction endonucleases showed two types of pattern, one present in Sultan and the other in the remaining six cultivars. A copy-number reconstruction indicated the presence of about three gene copies per haploid genome. Analysis of the six available whole chromosome addition lines and selected telocentric chromosome additions of barley into wheat showed the location of genes on the short arm of chromosome 2 (probably one copy) and the long arm of chromosome 4 (probably two copies).
Female pheromones inDrosophila melanogasterare controlled by the doublesex locus
Authors: Jallon Jean-Marc , Lauge Ginette , Orssaud Luc , Antony Claude 
Published: September 2009

SummaryXYandXX doublesex D. melanogaster, expressing variable intersexual phenotypes, were compared for their pheromone levels (e.g. 7, 11-heptacosadiene, the main excitatory pheromone of females, and vaccenyl acetate, an inhibitory compound produced only by males). Despite the intersexual phenotype and the presence of female traits, the pheromone patterns of the homozygousdsxmutants,XYas well asXX, were similar to those of heterozygous males. Female-specific dienes were never found in significant amounts in such flies, which often showed significant amounts of the male-specific acetate and triggered very reduced levels of male courtship wing vibration.
Esterase alleles of inbred mouse strains maintained in The Netherlands
Authors: Hilgers J. , von Deimling O. , van Zutphen L. F. M. , ten Berg R. , Anand R. , Festing M. F. W. 
Published: September 2009

SummaryFifty-seven mouse strains were examined for genetic variation at 21 esterase loci. Three new alleles were found:Es-6din strain A/WySna,Es-llein FTC/CpbU andEs-18cin two WLL/BrA sublines. At most loci there was a single allele found in over 80% of strains, with one or two rare alleles. However, theEs-1, 3, 10, 13, 25and27loci were much more polymorphic. Although several loci were linked on chomosomes 3, 8 and 9, linkage disequilibrium was only found betweenEs-5andEs-11(chromosome 8) andEs-26andEs-27(chromosome 3). There was also significant disequilibrium betweenEs-1and3, Es-1and10, andEs-3and10, which are on different chromosomes, suggesting that the 57 strains are not a random sample of inbred mouse strains. Fifty-four strains were closely related, with theEs-7b, –17a, –18a, –23cset of alleles, which are typical ofMus musculus domesticus. The three exceptional strains were MOL3 (Mus musculus molossinus), WLL/BrA (English–Norwegian origin) and TA2 (Chinese origin). There were 10 groups of strains which were identical at all loci. Sublines of the same strain were usually identical. Sometimes more distantly related strains, such as CBA/Bi, C3H/He, SM and DBA/Li, were identical, and in a few cases strains with no known common ancestry such as C58 and MAS were identical. Attempts to discriminate between a subset of 22 American and 15 European strains were unsuccessful, suggesting that the European strains add only in a quantitative manner to the gene pool of ‘laboratory mice’, whereas wild-derived strains such as MOL3 are genetically quite distinct from other laboratory mice.
Unusual behaviour of linkage disequilibrium in two-locus gene conversion models
Authors: Walsh J. Bruce 
Published: September 2009

SummaryThe amount of linkage of disequilibrium maintained in a two-locus infinite population model by gene conversion and recombination is examined. Intrachromosomal conversion (conversion between different loci on the same chromosome) generates positive linkage disequilibrium. Specifically,=p(1 −p) [1 −r/(γ +r− γr)], wherepis the frequency of alleleAat both loci,ris the recombination rate between loci and γ is the per-gamete conversion rate. Somewhat unexpectedly, interchromosomal conversion (conversion between loci on different chromosomes) also generates positive disequilibrium, albeit very small. More interestingly, the behaviour of this disequilibrium as a function of recombination is unusual. If β is the interchromosomal conversion rate between a pair of loci, then=p(1 −p) [rβ/(β+r− βr)].increaseswith increasing recombination, being zero for the case of complete linkage (r= 0), and maximized atr= 1/2. This unusual behaviour can be accounted for by the generation of excess coupling gametes when an interchromosomal conversion event is followed by recombination.
Selection for recombination in a polygenic model – the mechanism
Authors: Smith J. Maynard 
Published: September 2009

SummaryA polygenic model has been simulated in order to reveal the process whereby selection in an infinite population can lead to an increase in the frequency of alleles causing higher rates of recombination (CHalleles). Directional selection generates repulsion linkage disequilibrium (+ − + −), which is less strong inCHgametes (gametes carryingCHalleles). In consequence,CHgametes contribute greater phenotypic variability, and therefore respond more to directional selection: that is, they accumulate more selectively favoured alleles.CHalleles then increase in frequency by hitch-hiking. In contrast, normalizing selection, or frequent changes in the direction of selection, favour alleles for a low recombination rate.
Mutations affecting cysteine synthesis in Aspergillus nidulans: characterization and chromosome mapping
Authors: Cybis Jan , Natorff Renata , Lewandowska Irmina , Prazmo Wieslawa , Paszewski Andrzej 
Published: September 2009

SummarySelection and mapping of mutations affecting cysteine synthesis in Aspergillus nidulans was carried out. A new locus, cysE, is described, the mutants of which are deficient in in vivo conversion of O-acetylserine to cysteine, a step mediated by cysteine synthase. Three loci (cysB, C and E) were thus found to control this step in vivo, apparently without affecting the enzyme activity in vitro. By scoring for propargylglycine sensitivity of cys mutants, chromosomal map positions were obtained for all five cysteine loci (A, B, C, D and E).