bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genetic contribution to sex determination in turtles with environmental sex determination
Authors: Girondot Marc , Zaborski Patrick , Servan Jean , Pieau Claude 
Published: September 2009

SummaryIn many reptiles, sex determination is temperature-sensitive. This phenomenon has been shown to take place in the laboratory as well as in nature, but its effect on natural populations remains questionable. In the turtleEmys orbicularis, the effects of temperature override a weak mechanism of genetic sex determination which is revealed in incubation at pivotal temperature. At this temperature, the sexual phenotype is concordant with the expression of the serologically defined H-Y antigen (H-Ys) in non-gonadal tissues; males are H-Ys negative (H-Y−) whereas females are H-Ys positive (H-Y+). To estimate the importance of sexual inversion (sexual phenotype and H-Ys expression discordant) in populations of Brenne (France), the frequencies of male and female sexual phenotypes among H-Ys phenotypes were determined. The frequencies of sex reversed individuals are low, only 6 % of phenotypic females being H-Y−and 11 % of phenotypic males being H-Y+. According to these data, two theoretical models have been constructed to estimate the contribution to sex determination of individuals in relation to their genotype. The first model excludes any influence of incubation temperature and sexual phenotype on the fitness of individuals. The second one considers that these parameters influence fitness because this model has been previously shown to favour environmental sex determination. In both models, it appears that sex determination can be viewed as genotypic and monogenic with some individuals sexually inverted by theaction of temperature. One category of homozygous animals differentiates mainly into one sex, and the heterozygous animals differentiate mainly into the other sex. The second category of homozygotes has a low frequency in the populations and can differentiate as male or female without high constraint. Then it is estimated that in Brenne approximately 83% of the eggs are incubated in conditions allowing the genetic component to influence sex determination.
Direct determination of retrotransposon transposition rates inDrosophila melanogaster
Authors: Nuzhdin Sergey V. , Mackay Trudy F. C. 
Published: September 2009

SummaryRates of transposition and excision of theDrosophila melanogasterretrotransposon elementsmdg3, 297, Doc, rooandcopiawere estimated directly, byin situhybridization analysis of their cytological insertion sites in 31 replicates of a highly inbred line that had accumulated spontaneous mutations for approximately 160generations. Estimated transposition rates ofDoc, rooandcopiawere, respectively, 4·2 × 10−5, 3·1 × 10−3and 1·3 − 10−3; no transpositions of297normdg3were observed. Rates of transposition ofcopiavaried significantly among sublines. Excisions were only observed forrooelements, at a rate of 9·0 × 10−6per element per generation. Copy number averaged over these element families increased 5·9 %; therefore, in these lines the magnitude of the forces opposing transposable element multiplication were weaker than transposition rates.
Population dynamics of the copia, mdg1, mdg3, gypsy, and P transposable elements in a natural population ofDrosophila melanogaster
Authors: Biémont C. , Lemeunier F. , Guerreiro M. P. Garcia , Brookfield J. F. , Gautier C. , Aulard S. , Pasyukova E. G. 
Published: September 2009

SummaryThe insertion site polymorphism of the copia, mdg1, mdg3, gypsy, and P transposable elements was analysed byin situhybridization to the polytene chromosomes in genomes of males from a natural population ofDrosophila melanogaster. Parameters of various theoretical models of the population biology of transposable elements were estimated from our data, and different hypotheses explaining TE copy number containment were tested. The copia, mdg1 and gypsy elements show evidence for a deficiency of insertions on the X chromosomes, a result consistent with selection against the mutational effects of insertions. On the contrary, mdg3 and P copy numbers fit a neutral model with a balance between regulated transposition and excisions. There is no strong evidence of a systematic accumulation of elements in the distal and proximal regions of the chromosomes where crossing over and ectopic exchanges are reduced. For all chromosome arms but 3L, however, the TE site density increases from the proximal to the distal parts of the chromosomes (the centromeric regions were excluded in this analysis) with sometimes a sharp decrease in density at the extreme tip, following in part the exchange coefficient. The way the copy number of TEs is contained in genomes depends thus on the element considered, and on various forces acting simultaneously, indicating that models of TE dynamics should include details of each element.
Erratum
Authors: West John D. , Flockhart Jean H. 
Published: September 2009

Genet. Res., Camb. (1994), 63, pp. 87–99Genotypically unbalanced diploid ↔ diploidfoetal mouse chimaeras:possible relevance to human confined mosaicismJohn D. West, and Jean H. FlockhartThe sentence starting in the middle of line 16 of the Summary should readIn 20/38 chimaeric conceptuses in the unbalanced
Genetic models for the inheritance of the silver colour mutation of foxes
Authors: Skjøth Flemming , Lohi Outi , Thomas Alun 
Published: September 2009

SummaryWe consider genetic models for the inheritance of the particular colour patterns of silver foxes. The models are evaluated by computation of statistical likelihoods based on observations of related foxes in extended pedigrees. Problems caused by incomplete paternity information are addressed by inferences based on phenotypic observations. The unreliability of subjective evaluations of fur colour also provides difficulty, in particular crossfoxes emerge as being difficult to differentiate. No evidence of linkage between Agouti locus and Extension locus is found in this dataset.
Mini-mouse: phenotypic characterization of a transgenic insertional mutant allelic to pygmy
Authors: Benson Kathleen F. , Chada Kiran 
Published: September 2009

SummaryA phenotypic analysis was performed on two alleles at the pygmy locus which arose by insertional mutagenesis in transgenic mice. Similar to the spontaneous mutant pygmy, the adult insertional transgenic mutants are 40% of the size of wild-type litter-mates whereas adult heterozygotes are 80% of wild-type litter-mates. An analysis of the various organs revealed that, in general, there was a reduction in weight of each organ commensurate with the overall reduction in body size. However, two organs did not follow this pattern, the brain being disproportionately larger and the adrenals disproportionately smaller in the mutant mice. In addition, mini-mice have less adipose tissue than their wild-type or heterozygous litter-mates. A developmental analysis determined that mutants could first be identified on the basis of reduced body weight at day 15·5 of gestation. The small size is not due to a growth hormone deficiency so these mice differ from other known dwarf mouse mutants. Therefore they should provide insight into the growth hormone-resistant human dwarnsms and help in furthering our knowledge of mammalian growth and development.
Phenotypic effect of substitutions of short chromosomal segments containing different alleles of histone HI genes in garden pea (Pisum sativum L.)
Authors: Bogdanova V. S. , Rozov S. M. , Trusov Y. A. , Berdnikov V. A. 
Published: September 2009

SummaryA hypothesis has been tested that alterations in the molecule of histone H1 are capable of influencing quantitative traits of an organism. Two pairs of isogenic lines were constructed by selfing of plants kept heterozygous either for allelic variants of histone H1 subtype 1 (His1 gene) or for allelic combinations (haplotypes) of closely linked genes of H1 subtypes 3, 4, 5 and 6 (gene clusterHis(2–6)). After 19 and 15 generations of selfing, respectively, expectation of the length of chromosome which remained heterozygous has comprised 2·6 cM nearHisl and 3·5 cM nearHis(2–6). The third pair of isogenic lines was obtained as a result of two successive intracluster cross-over events bordering the gene of the subtype 5 (His5). In each pair of isogenic lines there have been revealed some statistically significant differences between mean values of a number of quantitative traits.
Estimating the covariance structure of traits during growth and ageing, illustrated with lactation in dairy cattle
Authors: Kirkpatrick Mark , Hill William G. , Thompson Robin 
Published: September 2009

SummaryQuantitative variation in traits that change with age is important to both evolutionary biologists and breeders. We present three new methods for estimating the phenotypic and additive genetic covariance functions of a trait that changes with age, and illustrate them using data on daily lactation records from British Holstein—Friesian dairy cattle. First, a new technique is developed to fit a continuous covariance function to a covariance matrix. Secondly, this technique is used to estimate and correct for a bias that inflates estimates of phenotypic variances. Thirdly, we offer a numerical method for estimating the eigenvalues and eigenfunctions of covariance functions. Although the algorithms are moderately complex, they have been implemented in a software package that is made freely available.Analysis of lactation shows the advantages of the new methods over earlier ones. Results suggest that phenotypic variances are inflated by as much as 39 % above the underlying covariance structure by measurement error and short term environmental effects. Analysis of additive genetic variation indicates that about 90 % of the additive genetic variation for lactation during the first 10 months is associated with an eigenfunction that corresponds to increased (or decreased) production at all ages. Genetic tradeoffs between early and late milk yield are seen in the second eigenfunction, but it accounts for less than 8 % of the additive variance. This illustrates that selection is expected to increase production throughout lactation.
TheHermestransposable element from the house fly,Musca domestica, is a short inverted repeat-type element of thehobo, Ac, andTam3(hAT) element family
Authors: Warren William D. , Atkinson Peter W. , O'Brochta David A. 
Published: September 2009

SummaryThe genome of the house fly,Musca domestica, contains an active transposable element system, calledHermes. Using PCR and inverse PCR we amplified and sequenced overlapping segments of severalHermeselements and from these data we have constructed a 2749 bp consensusHermesDNA sequence.Hermestermini are composed of 17 bp imperfect inverted repeats that are almost identical to the inverted terminal repeats of thehoboelement ofDrosophila melanogaster. Full lengthHermeselements contain a single long ORF capable of encoding a protein of 612 amino acids which is 55% identical to the amino acid sequence of thehobotransposase. Comparison of the ends of theHermesandhoboelements to those of theAcelement ofZea mays, and theTam3element ofAntirrhinum majus, as well as several other plant and insect elements, revealed a conserved terminal sequence motif. ThusHermesis clearly a member of thehobo,AcandTam3(hAT) transposable element family, other members of which include theTaglelement fromArabidopsis thalianaand theBgelement fromZea mays. The evolution of this class of transposable elements and the potential utility ofHermesas a genetic tool inM. domesticaand related species are discussed.
At least four genes and sex are associated with susceptibility to urethane-induced pulmonary adenomas in mice
Authors: Festing Michael F. W. , Yang Aili , Malkinson A. M. 
Published: September 2009

SummarySusceptibility to urethane-induced lung adenomas in mice has a polygenic mode of inheritance, with no obvious discontinuity in lung tumour counts among 37 AXB recombinant inbred strains. However, mean tumour counts were markedly higher in strains carrying the A/J allele at theKras2andH2complex than in those carrying the C57BL/6 allele. In 162 F2hybrids and small numbers of both backcrosses between strain A/J (susceptible) and C57BL/6 (resistant) mice, five factors influencing susceptibility were identified. Variation due to the ‘major’Kras2locus (chromosome 6) accounted for 60% of the total variation. ‘Minor’ loci linked to microsatellite markersTnfb(in theH2complex),D9Mit11andD19MH16(on chromosomes 17, 9 and 19, respectively) accounted for a further 13% of the variation, and males had more tumours than females with sex differences accounting for 2% of the variation. No significant association with 32 other loci was detected. On a square-root transformed scale, heterozygotes at all marker loci were of intermediate susceptibility compared with homozygotes. Thethree minor loci and sex only affected lung tumour counts when at least one susceptibleKras2allele was present.
The HSR on chromosome 1 of the house mouse, Mus domesticus: distribution and frequency in Switzerland
Authors: Hübner Roland , Maddalena Tiziano , Searle Jeremy B. , Vogel Peter 
Published: September 2009

SummaryA total of 357 house mice (Mus domesticus) from 83 localities uniformly distributed throughout Switzerland were screened for the presence of a homogenously staining region (HSR) on chromosome 1. Altogether 47 mice from 11 localities were HSR/ + or HSR/HSR. One sample of 11 individuals all had an HSR/HSR karyotype. Almost all mice with the variant were collected from the Rhone valley (HSR frequency: 61%) and Val Bregaglia (HSR frequency: 81%). For samples from most of thearea of Switzerland, the HSR was absent. There was no strong association between the geographic distribution of the HSR and the areas of occurrence of metacentrics. However, at Chiggiogna the HSR was found on Rb (1·3). Possible explanations for the HSR polymorphism are discussed.
The testis-determining gene, SRY, exists in multiple copies in Old World rodents
Authors: Nagamine Claude M. 
Published: September 2009

SummarySRY is a unique gene on the Y chromosome in most mammalian species including the laboratory mouse, Mus musculus, and the closely related European wild mouse species M. spicilegus, M. macedonicus, and M. spretus. In contrast, SRY is present in 2–6 copies in the more distantly related Asian mouse species M. caroli, M. cervicolor, and M. cookii and in 2–13 copies in the related murid species Pyromys saxicola, Coelomys pahari, Nannomys minutoides, Mastomys natalensis, and Rattus norvegicus. Copy numbers do not correlate with known phylogenetic relationships suggesting that SRY has undergone a rapid and complex evolution in these species. SRY was recently proposed as a molecular probe for phylogenetic inferences. The presence of multiple SRY genes in a wide range of murid species and genera, and at least one cricetid species, necessitates caution in the use of SRY for phylogenetic studies in the Rodentia unless it is ascertained that multiple SRY genes do not exist.
Sex differences in chiasma distribution along two marked mouse chromosomes: differences in chiasma distribution as a reason for sex differences in recombination frequency
Authors: Gorlov Ivan P. , Zhelezova Antonina I. , Gorlova Olga Yu. 
Published: September 2009

SummaryChiasma distributions along bivalents 1 and 14 in female and male mice were studied. It was shown that the average chiasma number in both chromosomes show no sex difference. There are however, significant sex differences in chiasma distribution along 1 and 14 chromosomes. In males there are two terminal chiasma peaks in chromosome 1 and one subtelomeric peak of chiasmata in chromosome 14. In females chiasma distributions are more even. According to genetic data, females produce more recombinants between loci of chromosome 1 than males do. By means of a computer simulation it was demonstrated that the differences in the average recombination frequency result from differences in chiasma distribution.
Spatially regulated expression of retrovirus-like transposons duringDrosophila melanogasterembryogenesis
Authors: Ding Dali , Lipshitz Howard D. 
Published: September 2009

SummaryOver twenty distinct families of long terminal direct repeat (LTR)-containing retrotransposons have been identified inDrosophila melanogaster. While there have been extensive analyses of retrotransposon transcription in cultured cells, there have been few studies of the spatial expression of retrotransposons during normal development. Here we report a detailed analysis of the spatial expression patterns of fifteen families of retrotransposons duringDrosophila melanogasterembryogenesis (17.6,297,412,1731,3S18,blood,copia,gypsy,HMS Beagle,Kermit/flea,mdg1,mdg3,opus,roo/B104andspringer). In each case, analyses were carried out in from two to four wild-type strains. Since the chromosomal insertion sites of any particular family of retrotransposons vary widely among wild-type strains, a spatial expression pattern that is conserved among strains is likely to have been generated through interaction of host transcription factors withcis-regulatory elements resident in the retrotransposons themselves. All fifteen families of retrotransposons showed conserved patterns of spatially and temporally regulated expression during embryogenesis. These results suggest that all families of retrotransposons carrycis-acting elements that control their spatial and temporal expression patterns. Thus, transposition of a retrotransposon into or near a particular host gene-possibly followed by an excision event leaving behind the retrotransposon'scis-regulatory sequences-might impose novel developmental control on such a host gene. Such a mechanism would serve to confer evolutionarily significant alterations in the spatio-temporal control of gene expression.
The distribution of transposable elements within and between chromosomes in a population ofDrosophila melanogaster. III. Element abundances in heterochromatin
Authors: Charlesworth Brian , Jarne Philippe , Assimacopoulos Stavroula 
Published: September 2009

SummaryThe total genomic copy numbers of ten families of transposable elements ofDrosophila melanogasterin a set of ten isogenic lines derived from a natural population were estimated by slot-blotting. The numbers of euchromatic copies of members of each family were determined for each line byin situhybridization of element probes to polytene chromosomes. Heterochromatic numbers were estimated by subtraction of the euchromatic counts from the total numbers. There was considerable variation between element families and lines in heterochromatic abundances, and the variance between lines for many elements was much greater for the heterochromatin than for the euchromatin. The data are consistent with the view that much of the β-heterochromatin consists of sequences derived from transposable elements. They are also consistent with the hypothesis that similar evolutionary forces control element abundances in both the euchromatin and heterochromatin, although amplification of inert sequences derived from transposable elements may be in part responsible for their accumulation in heterochromatin.
Isolation, characterization and RFLP linkage mapping of a DNA repeat family ofSolanum spegazziniiby which chromosome ends can be localized on the genetic map of potato
Authors: Gebhardt C. , Eberle B. , Leonards-Schippers C. , Walkemeier B. , Salamini F. 
Published: September 2009

SummaryIn a random sample of 2263 cloned genomic DNA fragments of the wild potato speciesSolanum spegazziniisix related, highly repetitive fragments (SPG repeat family) were identified that were present in much higher copy numbers inS. spegazziniiwhen compared with the closely related cultivated potatoS. tuberosum. The SPG repeat family was organized in long arrays of multiple copies. Cross hybridization experiments with 29 wild and cultivatedSolanumspecies and with the related tomato showed specificity of the SPG repeat family for tuber-bearingSolanumspecies. Among tuber bearingSolanumspecies a high degree of variation was observed for restriction fragment length and copy number. The variation in copy number was not correlated with established taxonomic relationships between tuber-bearingSolanumspecies. DNA sequence analysis revealed a subrepeat structure of 120–140 base pairs embedded in longer repeat units of variable length. Length polymorphisms between highly repeated restriction fragments detected by the SPG probes were used for segregation- and linkage analysis in four mapping populations of potato, for which RFLP maps had been constructed. Twelve loci were identified, eleven of which mapped to the distal ends of nine linkage groups. All the evidence suggested that the SPG repeat family represents a satellite repeat members of which are localized in the subtelomeric region of potato chromosomes. The SPG repeat family could be used, therefore, for completing the genetic map of potato.
The inbreeding decline and average dominance of genes affecting male life-history characters inDrosophila melanogaster
Authors: Hughes Kimberly A. 
Published: September 2009

SummaryThis paper describes the results of assays of male life-history characters in a large outbred laboratory population ofD. melanogaster. Lines of flies homozygous for the entire third chromosome and lines of flies carrying two different third chromosomes were assayed for agespecific male mating ability (MMA), age-specific survivorship, male fertility, and body mass. The results of these assays were used to calculate the inbreeding decline associated with each of these traits, the average dominance of deleterious alleles that affect the traits, the genotypic and environmental components of variance for the homozygous lines, and phenotypic and genotypic correlations among the characters. Significant inbreeding decline was found for all characters except the Gompertz intercept and fertility. Early and late MMA show larger effects of inbreeding than any other trait. The inbreeding load for MMA is about the same magnitude as that for egg-to-adult viability, but is substantially less than that associated with total fitness. The estimated inbreeding decline and average dominance of male life-history characters are comparable to estimates for otherDrosophilafitness components.