bluuebunny/crossref_metadata_2025_split huggingface dataset:
A new type of genetic control of gene conversion, fromAscobolus immersus
Authors: Lamb B. C. , Helmi S. 
Published: September 2009

SUMMARYA new type of genetic control of gene conversion is described from the Pasadena strains of the fungusAscobolus immersus. It is characterized bycis/transposition effects and incomplete dominance. TheP, Kand91factors segregated from each other like Mendelian alleles and controlled the conversion frequencies and patterns of four nearby, closely-linkedwhiteascospore colour mutations, although they did not usually coconvert with thesewsites. Mutations of different origin responded similarly to the same control factors.These control factors greatly affected the total conversion frequencies, the relative frequencies of the different detected conversion classes and various other conversion parameters. The detailed results are consistent either withP, Kand91affecting both the frequency of hybrid DNA formation and the correction processes for removing mispaired bases, or if they do not affect the correction processes directly, then they must have large effects on the frequency of asymmetrical hybrid DNA formation, which must usually be much more common than symmetric hybrid DNA, and there must be both an inequality in the frequency with which the two homologous chromosomes (in these crosses, + bearing andwbearing) invade each other, and in the frequency with which the two strands of each chromatid invade the homologue in asymmetric hybrid DNA formation.
Non-mendelian female sterility inDrosophila melanogaster: variations of chromosomal contamination when caused by chromosomes of various inducer efficiencies
Authors: Pélisson Alain 
Published: September 2009

SUMMARYA quite specific kind of sterileF1female, calledSFfemales, arises only when females of strains denoted reactive are crossed with males of the other class (inducer). It was previously shown that this sterility results from a nucleocytoplasmic interaction between the maternal reactive cytoplasm and a factor, calledI, which may be born by any one of the paternal chromosomes. InSFfemales, but not in their brothers, a varying proportion of reactive chromosomes are able to acquire irreversibly theIfactor, independently of any classical genetic recombination with the inducer chromosome(s). During this process, called chromosomal contamination, the contaminating chromosome(s) do not undergo any apparent change. The present paper deals with the efficiency of both original inducer and contaminated chromosomes to yield a more or less intenseSFsterility. TheOtanuinducer laboratory strain contains at least two types ofXchromosomes (calledstrongandweak) which differ genetically with respect to their inducer efficiency. Reactive third chromosomes were contaminated by thesestrongorweak Xchromosomes and their inducer efficiencies compared. Results show that they are on averagestrongerwhen they have been contaminated bystrong Xchromosomes than when contaminated byweakones. Such a correlation favours the hypothesis that chromosomal contamination is due to the insertion of some genetic element(s) into reactive chromosomes.
Analysis of central equilibrium configurations for certain multi-locus systems in subdivided populations
Authors: Karlin Samuel , Campbell R. B. 
Published: September 2009

SUMMARYThe multi-locus systems expressing non-epistatic and generalized symmetric selection lend themselves to the study of the stability of certain central polymorphic equilibria. These equilibria persist when any form of migration connects demes which share a common equilibrium. The analysis of the stability of the equilibrium in the global system is tractable, thus supplementing known protection results for two alleles at one locus with stability conditions on an internal equilibrium involving an arbitrary number of loci, each with an arbitrary number of alleles. Two of the principal findings are that stability of central Hardy–Weinberg type equilibria increase with ‘more’ migration and ‘more’ recombination. As a corollary, local stability in each deme implies stability in a system with migration superimposed; but instability in each deme when isolated does not imply instability when migration is superimposed.
Growth hormone function in strains of mice selected for large and small size
Authors: Pidduck Heather G. , Falconer D. S. 
Published: September 2009

SUMMARYThe gene (dw) causing hypopituitary dwarfism was transferred by repeated backcrosses into strains of mice differing genetically in growth-rate through previous selection. The dwarf mice lack growth hormone, and the purpose was to find out if the differences in growth-rate between the strains were in any part due to differences in their growth hormone status – amount of hormone or tissue sensitivity. In the absence of growth hormone, i.e. in the dwarfs, the strains still grew at different rates, proving that growth hormone status was not the only cause of their differences. The effect of substituting the dw gene was, however, greater in the large strain than in the unselected control, and less in the small strain than in the control. The growth differences between the strains were therefore in part due to growth hormone. Tissue sensitivity in the three strains was compared by their responses to graded doses of exogenous growth hormone. The large and control strains did not differ, but the small strain had a lower sensitivity. The results suggest that the increased growth-rate of the large strain is partly due to an increased amount, or activity, of its circulating growth hormone, while the reduced growth-rate of the small strain is in part due to a reduced sensitivity of its target organs to growth hormone.
Some approaches to the question of Drosophila laterality
Authors: Ehrman Lee , Thompson James N. , Perelle Ira , Hisey Brent N. 
Published: September 2009

SUMMARYThe question of Drosophila laterality has been investigated in two species and in several strains by attempting to modify degrees of laterality (wing folding and directional choices in mazes) via selection and by ascertaining individual courtship behaviour preferences (circling, foreleg tapping, and wing extending). The results of courtship studies in D. paulistorum strains and in D. melanogaster indicate that, although individual members of a strain may be entirely right or left dominant, the majority of individuals are ambidextrous. As a group, there was no preference for right or left behaviours, and laterality was not a factor in success of courtship. The absence of lateral preference in courtship is consistent with the failure to demonstrate any genetic component for D. melanogaster left and right wing folding and maze behaviours.
Evidence for a transmissible catabolic plasmid inPseudomonas putidaencoding the degradation ofp-cresol via the protocatechuateorthocleavage pathway
Authors: Hewetson L. , Dunn H. M. , Dunn N. W. 
Published: September 2009

SUMMARYEvidence is presented that a strain ofPseudomonas putidaharbours a catabolic plasmid which encodes for the degradation ofp-cresol through the protocatechuateorthocleavage pathway. This plasmid can transfer giving approximately 10−3transconjugants per donor cell, can be cured with mitomycin C, belongs to the P-9 plasmid incompatibility group and can be transduced with the bacteriophage pf16.
Estimation of heritability by regression using collateral relatives: linear heritability estimation
Authors: Hill William G. 
Published: September 2009

SUMMARYThe method of heritability estimation proposed by Abplanalp (‘linear heritability’ estimation) is reviewed and the formulation simplified. It is equivalent to the regression of performance of sibs of an individual, itself excluded, on that of the individual. The method is found to be slightly biased in small samples but, in terms of sampling variance, can make efficient use of the data.
Non-mendelian female sterility and hybrid dysgenesis inDrosophila melanogaster
Authors: Picard G. , Bregliano J. C. , Bucheton A. , Lavige J. M. , Pelisson A. , Kidwell M. G. 
Published: September 2009

SUMMARYSystematic crosses between various strains ofDrosophila melanogasterlead in some cases to partly sterile F1females (SFfemales). Two main classes of strain, inducer and reactive, have been denned on the basis of this sterility, which shows very specific physiological features.SFfemales arise only when reactive females are crossed with inducer males. In contrast, F1females (RSF) produced by the reciprocal cross between inducer females and reactive males have normal fertility. All wild populations tested are of the inducer category, laboratory strains are either inducer or reactive. Sterility is the result of interaction between two genetic factors denotedIandR, respectively responsible for the inducer and reactive conditions and whose unusual genetic behaviour has been described in other papers. The present paper reports experiments showing that theI–Rinteraction is also responsible for high levels ofXnondisjunction and of mutation in theSFfemale germ-line. The analogy with the P-M system of Kidwell, Kidwell & Sved (1977b), is discussed as are also the implications of the existence of theI-Rsystem for spontaneous mutation research inD. melanogaster.
Parameters in gene conversion: An algebraic analysis of the hybrid DNA model at thegraylocus ofSordaria fimicola.
Authors: Kalogeropoulos Angelos , Thuriaux Pierre 
Published: September 2009

SUMMARYWe have extended previous algebraic analyses of aberrant segregation at thegraylocus ofSordaria fimicola(Whitehouse, 1965; Emerson, 1966; Fincham, Hill & Reeve, 1980) to the more complex situation where aberrant segregations are detected in three factor crosses involving two flanking markers. This algebra has been applied to sevengrayalleles which have been extensively characterized for their pattern of gene conversion and postmeiotic segregation by Kitani & Olive (1967). It is based on seven major types of aberrant segregation which can be distinguished in the presence of flanking markers spanning the converting site, and allows us to use up to six parameters to describe hDNA formation and mismatch repair. We present solutions which predict a spectrum of aberrant segregation fitting the experimental data at theP> 0·05 level for six of the seven alleles tested. They are consistent with the following properties of hDNA at thegraylocus: (1) the single stranded DNA transferred during hDNA formation has always the same chemical polarity. (2) hDNA is mostly, if not entirely, symmetric, and its probability of formation is constant over the whole gene. (3) Disparity in aberrant segregation is mostly, if not entirely due to disparity in mismatch repair.
Mechanism of suppression inDrosophila melanogasterVIII. Comparison ofsu(s) alleles for ability to suppress the mutants purple, vermilion, and speck
Authors: Jacobson K. Bruce , Grell E. H. , Yim John J. , Gardner April L. 
Published: September 2009

SUMMARYThe suppressor of sable [su(s)2] restores the function of vermilion (v), purple (pr) and speck (sp) as well as sable (s) inDrosophila melanogaster. In this report various alleles ofsu(s) are compared for their relative effectiveness on three target mutations,v,prandsp. Three criteria for suppression ofprandvwere employed: visible phenotype, eye pigment levels (drosopterins and xanthommatin) and enzyme levels (sepiapterin synthase and tryptophan oxygenase). Forsponly the visible phenotype was examined. By all three criteriaprwas found to be more easily suppressed thanv;vandspwere comparable. By use ofprwith various alleles ofsu(s) either homozygously or in heterozygous combination withsu(s)+, the extent of suppression ofprcan be best demonstrated by observing the levels of sepiapterin synthase; normal levels of drosopterins were found in females when sepiapterin synthase was only 20% of normal. On the other hand, the extent of suppression ofvis best demonstrated by the amount of xanthommatin eye pigment, because even the suppressed vermilion fly has < 10% of wild-type activity of tryptophan oxygenase when 1-day-old flies are examined; in older flies this enzyme can be as high as 50% of wild type. From these results we also demonstrated thatsu(s)2, and other alleles, are not recessive but, in heterozygous combination withsu(s)+, cause marked suppression ofprand slight, but reproducible, suppression ofv. The purple mutation, therefore, is particularly useful for studying the mechanism of suppression as well as for obtaining new mutant alleles ofsu(s).
Novel pleiotropic effect of rifampicin resistance mutation in aMicromonosporasp
Authors: Gadó István , Kari Csaba , Széll Valéria , Szvoboda György 
Published: September 2009

SUMMARYRifampicin-resistant mutants have been isolated from aMicromonosporasp. In one of these, rifampicin failed to inhibit [3H]UTP incorporation in osmotically shocked cells; consequently, resistance was probably not due to the alteration of rifampicin permeability. Parallel to the rifampicin resistance there was a substantial increase in the novobiocin sensitivity of the mutants. Rifampicin-sensitive revertants exhibited their original novobiocin sensitivity. At the same time there was no increase in their sensitivity towards coumermycin A1, an agent of related structure and activity. The possible mechanism for this pleiotropy is discussed.
Models of mitochondrial DNA transmission genetics and evolution in higher eucaryotes
Authors: Chapman Robert W. , Stephens J. Claiborne , Lansman Robert A. , Avise John C. 
Published: September 2009

SUMMARYThe future value of mitochondrial DNA (mtDNA) sequence information to studies in population biology will depend in part on understanding of mtDNA transmission genetics both within cell lineages and between animal generations. A series of stochastic models has been constructed here based on various possibilities concerning this transmission. Several of the models generate predictions inconsistent with available data and, hence, their assumptions are provisionally rejected. Other models cannot yet be falsified. These latter models include assumptions that (1) mtDNA's are sorted through cellular lineages by random allocation to daughter cells in germ cell lineages; (2) the effective intracellular population sizes (nM's) of mtDNA's are small; and (3) sperm may (or may not) provide a low level ‘gene-flow’ bridge between otherwise isolated female lineages. It is hoped that the models have helped to identify and will stimulate further empirical study of various parameters likely to strongly influence mtDNA evolution. In particular, critical experiments or measurements are needed to determine the effective sizes of mtDNA populations in germ (and somatic) cells and to examine possible paternal contributions to zygote mtDNA composition.
Association of the cyanogenic loci in white clover
Authors: Ennos Richard A. 
Published: September 2009

SUMMARYThe inheritance of cyanogenesis inTrifolium repensis governed by two unlinked genes, Ac/ac and Li/li which determine the presence/absence of cyanogenic glucosides and their hydrolysing enzyme linamarase respectively. Plants possessing dominant alleles at both loci release hydrogen cyanide when their leaves are damaged. Analysis of phenotype frequencies in ten natural populations showed a significant positive association in phenotypic state between these two loci within populations. Taking into account the results of a subsidiary study which showed no significant deviation from random mating in a natural population ofT. repens, the most likely explanation for the observed association in phenotypic state is selection favouring the cyanogenic phenotype.
Estimation and interpretation of genetic distance in empirical studies
Authors: Mueller Laurence D. , Ayala Francisco J. 
Published: September 2009

SUMMARYLinear functions of Nei's genetic-distance statistic are calculated frequently in the literature of population genetics. Variance estimates for these linear functions are either not presented or incorrectly calculated. Part of the problem stems from the common assumption that distance statistics are independent random variables. This assumption is not generally correct. We describe methods for estimating the variance of linear combinations of genetic-distance statistics. We also suggest a method for constructing confidence intervals on genetic-distance statistics when these values are small (< 0·10) and their distribution deviates substantially from normal.
Primary non-random X-inactivation caused by controlling elements in the mouse demonstrated at the cellular level
Authors: Rastan Sohaila 
Published: September 2009

SUMMARYPrevious studies have shown that different alleles of the mouseXchromosomal controlling element locus,Xce, cause non-randomX-chromosome inactivation as judged by variegation in the coats of female mice heterozygous for X-linked coat colour/structure genes, or Cattanach's translocation (Is (X; 7) Ct), or the relative activity of biochemical variants of theX-linked enzyme PGK. This paper presents evidence using the Kanda differential staining method on 6½ d.p.c. and 13½ d.p.c. female mouse embryos heterozygous for the markerXchromosome Is (X; 7) Ct and carrying differentXcealleles, that theXcelocus affects the randomness ofXchromosome inactivation. Furthermore the fact that a markedXceeffect is demonstrable in female embryos as early as 6½ d.p.c. (i.e. very soon after the initial time ofX-inactivation) is strong evidence that theXcelocus exerts its effect by causing primary non-randomX-inactivation rather than by cell selection after initial randomX-inactivation.
Mutations relieving hypersensitivity to paromomycin caused by ribosomal suppressors inPodospora anserina
Authors: Coppin-Raynal Evelyne , Le Coze Denise 
Published: September 2009

SUMMARYIn the fungusPodospora anserina, mutations were selected which relieved the hypersensitivity to paromomycin caused by four suppressors assumed to be ribosomal ambiguity mutations (su1–31,su1–49,su1–60,su2–5). Our first purpose was to isolate new antisuppressor mutations and in fact a new antisuppressor gene,AS7was uncovered. TheAS7–1mutant displays a pleiotropic phenotype and particularly a sporulation defect. On the other hand, a newsu1mutant was obtained which acts as a suppressor and also as an antisuppressor: it can specifically reduce the suppressor effect of certainsu2mutations. This property of somesu1andsu2mutations was already known. Apart from these mutations probably involved in the control of translational fidelity, six mutations conferring cross-resistance to paromomycin and neomycin were isolated. While four of them are localized in thePm1andPm2loci previously identified, the two others define a new gene which controls paromomycin and neomycin resistance,Pm3. Strains carrying thePm3–1allele are sensitive to temperature at the level of growth and sporulation. The three last mutations which were obtained confer no mutant phenotype when separated from thesu1background. They are closely linked to thesu2locus.
Conventional and unconventional analysis of an inversion inNeurospora
Authors: Turner Barbara C. , Perkins David D. 
Published: September 2009

SUMMARYIn(IL; IR)O Y348is a pericentric inversion of linkage group I inN. crassa, with a breakpoint betweenfrandun-5in the left arm and a breakpoint betweenad-9andnit-1in the right arm. Approximate breakpoint location was found by tabulating crossovers between the rearrangement and markers in normal chromosome sequence. Inversion structure was verified by markedIn O Y348×In O Y348crosses. Precise mapping of breakpoints was by duplication coverage. Inversions likeO Y348do not produce progeny with segmental chromosome duplications when crossed to normal sequence, but duplications were produced by crossing it toIn(IL; IR)O Y323(Barry & Leslie, 1982), another standard pericentric inversion, and toT(I → VI)NM103(Turner, 1977), a translocation to a tip. Each of these rearrangements has a breakpoint within the inverted region ofIn O Y348. Two duplications fromIn O Y348×In O Y323were converted to normal chromosome sequence by double mitotic recombination. Besides expediting mapping, the technique of intercrossing rearrangements increasingly enables us to make segmental duplications exactly tailored for studying specific included genes.
Temperature-sensitive paralytic mutations on the second and third chromosomes ofDrosophila melanogaster
Authors: Kulkarni Shankar J. , Padhye Asha 
Published: September 2009

SUMMARYSeven temperature-sensitive paralytic mutants were recovered from 4544 lines of ethylmethanesulphonate (EMS) treated autosomes inDrosophila melanogaster. These mutants have been designated temperature-induced paralytic (tip). Thetipmutations belong to six different genes; four of these,tip-A, Tip-B, tip-Candtip-Dare on the second chromosome whiletip-Eandtip-Fare on the third chromosome. This paper describes the paralysing behaviour and genetic localization of thetipmutants.
Competitive mating inDrosophila melanogaster
Authors: Sharp Paul M. 
Published: September 2009

SUMMARYSelective differences among maleDrosophila melanogasterdue to differences in ability to compete for mates may often have been under-estimated in the past because, under the test procedure used, females did not represent a limited resource. In the experiment reported here, no difference was detected between inbred and outbred males ‘competing’ to mate with an equal number of females. When the receptive female: male ratio was halved a large reduction in male mating ability due to inbreeding became apparent.
Location on chromosome 6 of the locus for a major liver protein (Lvp-1) of the house mouse
Authors: Wilcox Frank H. , Roderick Thomas H. 
Published: September 2009

SUMMARYThe linkage of the locus of the major liver protein,Lvp-1, has been established on chromosome 6. Testcross data show the following gene order and recombination percentages:centromere −Hd−7·4 ±2·4%−Lvp-1−13·2±3·1% −miData from 39 recombinant inbred strains show complete concordance of theLvp-1locus and theLyt-2locus on chromosome 6.
The phasmid as a tool for plasmid genetics: I. Fine structure of the β-lactamase gene
Authors: Castagnoli Luisa , Cesareni Gianni , Brenner Sydney 
Published: September 2009

SUMMARYThe reversible integration of a plasmid into a phage genome viaint-mediated recombination permits rapid and facile analysis of plasmid genes. Seventy-six independent mutants in theβ-lactamase(bla) gene have been isolated and genetically mapped. The end points of deletions generated by partial digestion with restriction enzymes have been identified and this, together with the assignment of some nonsense mutations to specific amino acid residues, allows alignment of the genetic map with the DNA sequence.