bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of selection on growth, body composition, and food intake in mice: III. Correlated responses:growth, body composition, food intake and efficiency and catabolism
Authors: Bishop S. C. , Hill W. G.
Published: September 2009

Weekly food intake and body weight were measured from 3 to 17 weeks of age on mice selected 14 generations for increased and decreased values of one of three criteria: appetite (A) as measured by 4- to 6-week food intake, adjusted by phenotypic regression to minimize change in 4-week body weight; fat percentage (F), using the ratio of gonadal fat pad weight to body weight at 10 weeks of age and total lean mass (protein, P), using the index body weight in 10-week males— (8 × gonadal fat pad weight). Carcass composition analyses were undertaken on the 17-week-old mice, and are presented along with composition data for younger mice from earlier generations. The high intake A line mice are larger, eat more, have higher maintenance requirements and are slightly leaner than the low intake A line mice, but are no more efficient. The increased lean mass P line mice are much larger, eat more and are more efficient than the decreased lean mass P line mice, but show little difference in maintenance or carcass composition. The (much) fatter F line mice are larger, more efficient and eat more during the rapid growth period than their leaner F line counterparts, but show no difference in lean mass or maintenance requirements. These results provide implications about the relationships between the input (intake) and output (maintenance and lean and fat deposition) components of growth.
‘Heterosis’ in litter size of chimaeric mice
Authors: Mikami Hitoshi , Onishi Akira
Published: September 2009

Aggregation chimaeras were made from embryos of C57BL/6 and BALB/c mice. Chimaeric and control females were mated with ICR males at 8 weeks of age and their litter sizes were evaluated over a 5-month period after the first mating. Progeny tests showed that 18 of 27 chimaeras produced oocytes of both genotypes. The mean litter sizes of C57BL/6, BALB/c and their F1crosses (C57BL/6 × BALB/c and BALB/c × C57BL/6) were 8·14, 9·36, 13·38 and 13·40, respectively. The mean for chimaeras was 11·54 and chimaeric heterosis was evident, but it was not as much as heterosis in the F1When the chimaeras were classified into the mixed and single-genotype progeny chimaeras, chimaeric heterosis was observed only in the mixed-progeny chimaeras. Quantitative GPI analyses in ten organs showed that the degree of chimaerism in the mixed-genotype progeny chimaeras was higher than that in most of the single-genotype progeny chimaeras and that the degree of chimaerism in the ovaries was positively correlated with litter size in the mixed-genotype progeny chimaeras. On the other hand, such correlation was not observed in the single-genotype progeny chimaeras.
A recessive allele of the mouse agouti locus showing lethality with yellow,Ay
Authors: Lyon Mary F. , Fisher G. , Glenister P. H.
Published: September 2009

The radiation-induced agouti allelea1is recessive to the allelesaanda4H(which resemblesae). It is lethal when homozygous and also in combination with the dominant yellow alleleAy. The ethylnitrosourea induced allelea16His also lethal when homozygous, and when heterozygous withashows a phenotype like that ofax, with black back and lighter belly. Likeaxit is not lethal withAy, and it is also not lethal witha1,a1is believed to be the first recessive allele which is lethal withAy, and may be useful in elucidating the complexity of the agouti locus.
Optimum selection strategies: studies with Drosophila melanogaster
Authors: García-Dorado Aurora , López-Fanjul Carlos
Published: September 2009

An experimental evaluation of Jódar & López-Fanjul's (1977) theoretical treatment of the optimum proportions to select when the numbers of males and females scored are unequal has been carried out for sternopleural bristle number in Drosophila melanogaster. Three different values of the sex-ratio (c) were considered (c = 1, 4 and 10) for the same total number of individuals scored per generation. For each c value two types of line were selected with proportions theoretically maximizing the response to be attained after 10 or 20 generations, respectively. Thus, there were six types of lines and each type was replicated sixfold. A good qualitative agreement was found between the observed and the expected rankings of the different types of selected lines at the designated generations.
Mating types and mating-inducing factors (gamones) in the ciliateEuplotes patellasyngen 2
Authors: Akada Rinji
Published: September 2009

Relationships between mating type genes and mating-inducing factors (gamones) were investigated in the ciliateEuplotes patellasyngen 2. Ten mating types were distinguished, and genetic data indicated that the ten mating types were determined by four codominant alleles in possible combinations of two of them. There were six heterozygous types (mt1/mt2,mt3/mt4, etc.) and four homozygous types (mt1/mt1,mt2/mt2, etc.). Conjugation-conditioned fluid (CCF) obtained from a mixture of cells of homozygous types could induce homotypic pair formation in cells of all mating types except for a particular type. Genetic data of cell-CCF combination experiments suggest that each mating type allele controls the production of a specific gamone which induces pair formation in cells which do not produce the same gamone. Gamones and their hypothetical receptors are discussed.
Genetic investigation of a negatively phototactic strain ofChlamydomonas reinhardtii
Authors: Smyth Robert D. , Ebersold W. T.
Published: September 2009

Two laboratory strains of the green algaChlamydomonas reinhardtii137cdiffer in their pattern of phototactic aggregation. One is positively phototactic under conditions where the other is negatively phototactic. The trait segregates 2:2 in tetrads and maps to a single locus. Heterozygous diploids are positively phototactic, showing that this allele is dominant. The aggregation pattern caused by either allele is not altered by the introduction of an unlinked gene that suppresses development of the eyespot. Probably the strains already differed in phototactic behaviour at the time they were first isolated. They may therefore reflect a genetic polymorphism common among soil algae. The genetic data allowed another significant observation not specifically related to phototaxis. Anomalous products from some crosses suggest that four nuclei sometimes fuse into a tetraploid zygote that then undergoes meiosis. The meiotic products that result are diploid. This represents a previously undescribed mechanism of diploid formation inChlamydomonas.
Site of beige (bg) and leaden (ln) pigment gene expression determined by recombinant embryonic skin grafts and aggregation mouse chimaeras employing sash (Wsh) homozygotes
Authors: Stephenson Dennis A. , Glenister Peter H. , Hornby Janet E.
Published: September 2009

Aggregation chimaeras were constructed by fusing embryos homozygous for sash (Wsh) with fuzzy, leaden beige (fz,ln,bg) homozygotes to investigate the site of action of the beige and leaden loci. The genotype of the hair follicle was identified by fuzzy alleles (+ +fzorfzfz). All melanocytes were derived from the fuzzy leaden beige population, as sash homozygotes do not produce functional melanocytes. Reciprocal recombinant epidermal/ /dermal skin grafts were constructed from 14-day embryonic skin of homozygousfzlnbg and either albino (aa cc) or pink-eyed dilution (pp) embryos to test for any dermal expression of leaden or beige, since the epidermal and dermal genotype of the chimaeric hair follicles could differ.

Patches of fuzzy and non-fuzzy hairs were distributed throughout the coats of two of the three chimaeras obtained. The pigmented regions were blue grey, typical of the leaden beige interactive phenotype. Large abnormal beige granules were found in fuzzy and non-fuzzy hairs. Melanocytes in both classes of growing follicles were nucleopetal, typical of leaden. Similarly, the results of the 14-day skin grafts showed that the beige and leaden loci are melanocyte-autonomous.

The chimaeras showed a pigment distribution resembling the heterozygous sash phenotype. Thus the 1:1 gene dosage of sash: wild type in heterozygotes and chimaeras has an overall effect on pigment pattern that overrides the predicted random distribution of the melanocyte precursors.
Virus-induced mutations in maize: on the nature of stress-induction of unstable loci
Authors: Peterson Peter A.
Published: September 2009

Unstable alleles, broken chromosomes and stable mutants have arisen in maize out of infected plants of Barley Striped Mosaic Virus and other viruses. Surprisingly, these same events have appeared out of progenies of these infected plants that themselves do not show any infection. These mutants showing instability have resulted from insertions that are not necessarily related. Two of these insertions (BS1 and TZ86) that have been analysed molecularly have the general characteristics of maize insertions with terminal inverted repeats and host duplication at the terminus of the transposon. In other experiments three of the unstable alleles at thealocus in maize (Alocus, chromosome 3, short arm; one of genes for anthocyanin control) that arose in derivative lines of the initially treated plants are responsive to a transposable element, theUqelement. It was determined that theUqelement was not present in this initially treated plant but was present in the untreated female plant. It is proposed that the initial treatment induced events that in turn led to the mobilization of elements and that these events continue to occur in later generations. It seems that genomic events once initiated such as mobility of elements cannot be terminated despite a discontinuation of the treatment (virus) and, like a Frankenstein monster, is not responsive to its maker.
Numbers and distribution of individuals and mating type alleles in populations of Coriolus versicolor
Authors: Williams E. N. D. , Todd N. K.
Published: September 2009

A natural population of the tetrapolar fungus Coriolus versicolor (L. ex Fr.) Quel, in a small woodland was observed over 3 years. Dikaryotic members of the population were identified using intraspecific antagonism and mating type markers. Records were kept of the distribution, longevity and fruiting behaviour of 44 individuals. Zone lines between individuals were found to remain constant in position throughout the study, but rates of decay and fruiting times varied between dikaryons and did not seem related to resource size. Detailed maps of the genetic structure of the populations in two stumps are presented. In general the results indicated thousands of alleles at both mating type loci. Repeated occurrences of alleles were very rare, when the data were interpreted rigorously in terms of the probable origins of the nuclei found in individuals. This approach was also applied critically to some published data. Comparisons were made between alleles found in local and more widely gathered samples, and led to estimation of worldwide frequencies but it is concluded that such exercises are of limited value.
Transmission of a genetic trait through total conjugation in a hypotrich ciliateParaurostyla weissei. Genetic basis of the multi-left-marginal mutant
Authors: Jerka-Dziadosz Maria , Dubielecka Bozena
Published: September 2009

The genetic basis of slow growth rate and aberrations in the ciliary pattern was studied in the multi-left-marginal variant ofParaurostyla weissei. The 3:1 segregation in F2 sibling crosses and 1:1 segregation in test crosses indicate that the aberrant phenotype is controlled by a recessive allele at a single gene locus termedmlm. The phenotypic change from wild type tomlmtakes place about 5–8 cell cycles after conjugation. The study established that total conjugation inP. weisseiis a true sexual process in which meiosis, fertilization and Mendelian segregation occur.
Meiotic behaviour of compound chromosomes in tricomplex heterozygotes inDrosophila melanogaster
Authors: Puro Jaakko
Published: September 2009

A tricomplex heterozygote has a synthetic chromosome complement consisting of four pairs of arms of chromosomes 2 and 3 in the form of a compound of two homologous arms (a homocompound) and of three compounds of two nonhomologous arms (heterocompounds), each being homologous to an arm of different compounds. In meiosis, pairing of homologous arms results in the formation of a single and a multiple configuration that are structural equivalents of a univalent and a trivalent. Data are presented indicating that, in a given complement, the pattern of the distribution of three heterocompounds at division I is the same in males and in females. The distribution depends on the arrangement of the 2nd and the 3rd chromosome centromeres in the trivalent. In configurations presumed to be homocentric (all three chromosomes having homologous centromeres), the distribution was random or nearly random while, in configurations presumed to be heterocentric, the distribution appears non-random, with one of the segregation alternatives being roughly twice as frequent as either one of the two other alternatives that were more or less equal in frequency. The results could be explained in terms of the 3rd chromosome centromere being ‘strong’ in directing the two 2nd chromosome centromeres to the opposite pole at division I, an explanation implying a functional differentiation of the two autosomal centromeres or adjacent sequences. Data are also presented showing that in females the distribution of the homocompound is non-random with respect to the distribution of the heterocompounds; the homocompound was recovered preferentially together with the single one of the three heterocompounds. This is inconsistent with the prediction based on the theory assuming an existence of two independent pairing pools.
Quantitative genetics and the evolution of ontogeny. III. Ontogenetic changes in correlation structure among live-body traits in randombred mice
Authors: Cheverud James M. , Leamy Larry J.
Published: September 2009

Ontogenetic series of phenotypic, additive genetic, maternal and environmental correlation matrices are presented and interpreted in the light of recent models for the Ontogenetic origin and variation in correlation between traits. A total of 432 mice from 108 full-sib families raised in a cross-fostering design were used to estimate the various components of phenotypic correlation for five live-body traits at eight ages. The level of genetic and phenotypic correlation decreased with age, while levels of maternal and environmental correlation remained more or less constant. Genetic correlations probably decreased due to compensatory growth. Phenotypic correlations decreased primarily due to the relative decrease in importance of highly correlated maternal effects and consequent increase in poorly correlated environmental effects as portions of phenotypic variation. The effect of compensatory growth on genetic correlation was also responsible for a portion of the decline in phenotypic correlation. Phenotypic correlation patterns remained constant over the ages studied here. It also seems likely the genetic, maternal and environmental correlation patterns do not change with age for the characters analysed.
A note on Fisher's ‘average effect’ and ‘average excess’
Authors: Falconer D. S.
Published: September 2009

The average effect and average excess of a gene substitution are formulated in terms of gene frequencies and inbreeding coefficient. This clarifies their meanings and shows how each is affected by non-random mating. The meanings of various definitions are examined, and one commonly used definition of average effect is found to be invalid with non-random mating. The concept of breeding value is shown to have no useful meaning when mating is not random.
Phosphatase regulation inAspergillus nidulans: responses to nutritional starvation
Authors: Caddick Mark X. , Brownlee Alan G. , Arst Herbert N.
Published: September 2009

The regulation of the syntheses of a number of phosphatases in the fungusAspergillus nidulanshas been examined. Levels of the intracellular alkaline phosphatase P11 are increased by starvation for carbon, nitrogen, phosphorus or sulphur. There is, however, no evidence that any of the wide domain regulatory genes which mediate sufficiency-triggered repression for each of these elements involved. A possible interpretation is that all four forms of starvation result in accumulation of an inducing metabolite. ThepalcA gene has been identified as a wide domain, probably positive-acting regulatory gene mediating phosphate repression. ThepalcA product controls the syntheses of alkaline phosphatase PI, acid phosphatases PIII and PV, a phosphodiesterase lacking phosphomonoesterase activity and probably also a phosphate permease. Mutations resulting in derepression of phosphate-repressible activities at acid but not alkaline growth pH define a gene designatedpacJ.pacJ mutations also confer arsenate resistance at low but not high pH. It is likely that phosphate derepression and arsenate resistance result from reduced uptake of H2PO4−. Finally, phosphatase regulation might be less complex than previously thought. Mutations designatedrand mapping at several loci apparently have no effect on phosphatase. They enhance phosphatase colony staining but this occurs even if the phosphatase substrates are omitted from the staining mixtures.rmutations appear to promote reactions converting the diazonium salts used for phosphatase staining to coloured precipitates.
Leaf peroxidases – A biochemical marker for the group 2 chromosomes in the Triticinae
Authors: Bosch Angeles , Figueiras Ana M. , Gonzalez-Jaen Maria T. , Benito Cesar
Published: September 2009

Structural genes for the leaf isozymes of peroxidases (E.C.1.11.1.7) have been located on chromosome arms 2BS, 2DS and probably 2AS of wheat, 2RS of cereal rye and on chromosome 2H ofHordeum vulgare. This character provides a useful genetic marker for these chromosome arms, and the results supports the notion of the conservation of gene synteny groups within the Triticinae.
The genetics of tasting in mice: IV. The acetates of raffinose, galactose and β-lactose
Authors: Lush Ian E.
Published: September 2009

Thirty strains of mice were tested for their ability to taste a 0·4 mM solution of raffinose undecaacetate (RUA). There were large strain differences. Some strains showed little or no ability to taste the RUA. Two strains, SWR and Schneider, could taste RUA because they possess the Soaa allele which enables them to taste a variety of acetylated monosaccharides. Three other strains, BALB/c, DBA/2 and C3H, could taste RUA because they possess the Ruaa allele which enables them to taste some larger structure which is a feature of the molecule as a whole. The gene Rua is tightly linked to the gene for quinine tasting. Qui, but the distribution of their alleles among the strains shows that they are different genes. It is suggested that there is in the mouse a cluster of tightly-linked genes, each one determining a taste receptor for a different bitter substance or chemical group. The relevance of these findings to the physiology of tasting is discussed.
The gene controlling the binding sites of Dolichos biflorus agglutinin, Dlb-1, is on chromosome 11 of the mouse
Authors: Uiterdijk H. G. , Ponder B. A. J. , Festing M. F. W. , Hilgers J. , Skow L. , Van Nie R.
Published: September 2009

A locus, Dlb-1, controlling the binding of the lectin from Dolichos biflorus to the intestinal epithelium and vascular endothelium of mice has been located on chromosome 11, 3.1 ± 1.4 centimorgans proximal to Rex, using recombinant inbred strains and conventional backcrosses with three-point linkage tests.

The two alleles so far discovered at this locus behave unusually. The Dlb-1a allele causes binding to the vascular endothelium but not to the intestinal epithelium while Dlb-1b induces the exact reciprocal binding pattern, and the heterozygote shows both patterns.
Genetic analysis of a new haplotype of the histidine decarboxylase gene complex in C57BL/6 mice
Authors: Martin S. A. M. , Bulfield Crahame
Published: September 2009

The histidine decarboxylase (HDC) gene complex, [Hdc], comprises the structural gene for mouse kidney HDC and closely linked regulatory elements which determine enzyme concentration and its response to hormones. One of these regulatory elements,Hdc-e, determines the response (induction or repression) of kidney HDC to oestrogen. HDC is oestrogen-inducible in C57BL/10 and oestrogen-repressible in DBA/2 and C57BL/6; alleles ofHdc-esegregate in crosses between C57BL/10 and DBA/2 and between the C57BL substrains. Two different haplotypes of[Hdc] have been defined previously, B.10 (Hdc-sb, Hdc-cb, Hdc-eb) in C57BL/10 and D (Hdc-sa, Hdc-cd, Hdc-ed) in DBA/2. C57BL/6 represents a third haplotype (B.6) (Hdc-sb, Hdc-cb, Hdc-ed) which differs from both B.10 and D.Hdc-emay therefore be a component of the complex independent ofHdc-sandHdc-c.
Location of genes controlling the D group of LMW glutenin subunits on chromosome 1D of bread wheat
Authors: Payne Peter I. , Roberts Mary S. , Holt Linda M.
Published: September 2009

Over one hundred backcross-one progeny were analysed by two dimensional electrophoresis to locate the genes on the short arm of chromosome 1D which code for, or control, the D group of LMW glutenin subunits. Recombination between these genes andGlu-D 1, encoding HMW glutenin subunits, was frequent but none could be detected between the D subunit genes andGli-D1, coding for ω-gliadins, γ-gliadins and the B group of LMW glutenin subunits. These results are in contrast to those for chromosome 1 B because apparently homoeologous D subunit genes occur at a different position, being equidistant betweenGlu-B 1(homoeologous toGlu-D 1) andGli-B 1(homoeologous toGli-D 1). A range of 18 genetically-diverse wheat varieties, each containing one of two allelic groups of 1 D-encoded D subunits, were also analysed by two-dimensional electrophoresis. Consistent with the genetic analysis above, unbreakable linkages were found between these alleles and alleles ofGli-D 1. The results are discussed in relation to the evolution of the distribution of prolamin genes in the wheat genome.
Hybrid dysgenesis inDrosophila melanogaster:synthesis ofRPstrains by chromosomal contamination
Authors: Kidwell Margaret G. , Sang Helen M.
Published: September 2009

Several strains have been synthesized which have reactive (R) properties in theI–Rsystem of hybrid dysgenesis and which are also classified as activePstrains in theP–Msystem. The synthesis of this previously unknown combination of types was accomplished by employing a mating scheme which allowed transposition (chromosomal contamination) ofP, but notI, factors fromIPtoRMchromosomes in dysgenic F1males. The successful synthesis ofRPstrains provides strong evidence that the apparent absence of this combination in natural and laboratory populations ofmelanogasteris not due to a biological incompatibility between these two types.
5-azacytidine-induced decrease in the frequency of Barr body in human fibroblasts
Authors: Mukherjee Asit B. , Luckett Deborah C. , Herrera Rene J.
Published: September 2009

5-azacytidine-treated human fibroblasts exhibit a significant decrease in the frequencies of Barr body+ cells as compared to nontreated cultures. This presumably indicates that 5-azacytidine can induce a change in the degree of condensation of the Barr body. It is suggested that the state of chromatin condensation of the Barr body may be related to the reactivation process by 5-azacytidine of gene loci in the inactive X.
The maintenance of polygenic variation through a balance between mutation and stabilizing selection
Authors: Barton N. H.
Published: September 2009

The 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

Denatured 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

The 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

A 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

A 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

Twelve 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. 175–178

A 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 9

In 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

rpoB 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

Sex 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. 11–18

A latitudinal cline in P–M gonadal dysgenesis potential in Australian Drosophila melanogaster populations

Figures 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

The 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

Linkage 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

Using 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

Wild 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

Testis 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

We 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

A 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

The 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

A 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

XYandXX 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

Fifty-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

The 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

A 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

Selection 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).