bluuebunny/crossref_metadata_2025_split huggingface dataset:
Implications of the genetic divergence between European wild mice with Robertsonian translocations from the viewpoint of mitochondrial DNA
Authors: Moriwaki Kazuo , Yonekawa Hiromichi , Gotoh Osamu , Minezawa Mitsuru , Winking Heinz , Gropp Alfred 
Published: September 2009

SUMMARYGenetic divergences between the wild mouse populations with various Robertsonian translocations from the Poschiavo Valley, Yugoslavia, Milan and the Apenninies, were estimated based on the mitochondrial (mt) DNAs. The mtDNAs isolated from the liver were analysed by agarose slab-gel electrophoresis after digestion with eight kinds of restriction endonucleases: BamHI, EcoRI, HindII, HindIII, PstI, HpaI, HpaII and BgII. These preparations were further used to make restriction maps, from which sequence divergence between each Rb variation was calculated to be 0·2–2·2%. These rather larger values appear to be in conflict with the present concept that the Rb variations occurred during the last several thousand years. Both, however, might be reconciled by assuming genetic introgression of the founder with a small number of Rb translocations into other subspecies populations genetically remote and the subsequent rapid accumulation of Rb translocations unique to each population due to an unknown mechanism occurring specifically in the intersubspecies hybrids betweenM. m. domesticusand the otherM. m. subspecies. This was the case also in a new Rb (9.15) translocation obtained from Ogasawara Islands in Japan which was the intersubspecies hybrid betweenM. m. molossinusandM. m. domesticus.
Chloroplast DNA diversity in wild and cultivated barley: implications for genetic conservation
Authors: Clegg M. T. , Brown A. H. D. , Whitfeld P. R. 
Published: September 2009

SUMMARYNine diverse lines of cultivated barley (Hordeum vulgare) and 11 lines of its wild progenitor (H. spontaneum) were assayed for variation in their chloroplast DNA by digestion with ten restriction endonucleases. The cultivated lines exhibited a single cpDNA polymorphism, whereas the wild material exhibited five. The significantly lower level of diversity among the cultivated lines was unexpected because both cultivated and wild lines had been selected for comparable levels of diversity for nuclear encoded isozyme loci. These results suggest that the level of cytoplasmic diversity was markedly restricted during the domestication of cultivated barley.
Hybrid dysgenesis inDrosophila melanogaster: partial sterility associated with embryo lethality in theP-Msystem
Authors: Kidwell Margaret G. 
Published: September 2009

SummaryVariable frequencies of unhatched eggs were observed to be produced by a number of F1interstrain hybrids. This type of partial sterility resulting from F2embryo death was found to be associated with theP-Msystem of hybrid dysgenesis. Dysgenic hybrid progeny of crosses betweenMstrain females andPstrain males may therefore have reduced fertility due to the disruption of development at two different stages: early F1gonadal development and early F2embryo development. These disruptions result in the previously described F1gonadal dysgenesis (GDsterility) and F2embryo lethality (ELsterility) respectively. The two morphologically distinct types ofP-M-associated sterility differ in their patterns of response to F1developmental temperature, and the temperature-sensitive period forELsterility occurs considerably later in F1development than forGDsterility.ELsterility is similar toSFsterility, which is associated with theI–Rsystem of hybrid dysgenesis in that both result from death during early F2embryogenesis. However,ELsterility differs fromSFsterility in not being restricted to hybrids of the female sex and in showing different patterns of response to temperature and ageing in the F1generation. Some implications of the existence ofELsterility for methods of strain classification in theI–Rsystem are explored.
Polymorphism of t-complex genes in European wild mice
Authors: Klein Jan , Sipos Peter , Figueroa Felipe 
Published: September 2009

SummaryThirty-two t haplotypes were extracted from wild mice captured in Central Europe, Spain, the Soviet Union, Israel, Egypt, the Orkneys and South and North America, and tested for lethality in the homozygous state. Twenty-two proved to be homozygous lethals, 8 semilethals and 2 viables. The lethal t haplotypes were then tested by the genetic complementation test for identity with representatives of known complementation groups and with each other. Five of the 22 haplotypes proved to carry previously identified lethality factors (tw5, tw73, and tLub-1), while the rest carried new factors. The 17 haplotypes fell into 8 new complementation groups. Two of the new groups are partially overlapping in that they seem to share some lethality factors and differ in others. These tests raise the total number of known complementation groups to 16. The distribution of the individual t haplotypes among wild mice populations seems to reflect their differentiation from a common ancestor haplotype.
Effects of selection on growth, body composition and food intake in mice: II. Correlated responses in reproduction
Authors: Brien Forbes D. , Sharp Gillian L. , Hill William G. , Robertson Alan 
Published: September 2009

SummaryFemale reproductive performance is reported in mice selected for ten generations for one of three criteria: either appetite (A), fat percentage (F) or total lean mass (P). For each criterion lines were selected for high (H) or low (L) performance, with contemporary unselected controls (C). In theAandPlines, litter size changed in the direction of the selected criterion, the changes being larger and more rapidly established in theAthan in thePlines. At generation 10, the differences in litter size between high and low lines were 2·6 live young born in theAlines, and 1·0 live young born in thePlines. The differences in 6-week weight between the high and low lines were 3·5 g in theAlines, 6·5 g in thePlines. Changes in ovulation rate were the primary reason for changes in litter size, the differences between the high and low lines being 3·8 corpora lutea for theAlines, and 3·1 corpora lutea for thePlines. Fitting body weight at mating as a covariate within lines in the analysis of ovulation rate and live foetus number removed the differences between the high and low selectedPlines, but not those in theAlines. The high and low selectedAandPlines did not differ in prenatal survival. There were no consistent differences in litter size, ovulation rate or pre-natal survival in theFlines.
Mapping of the genes controlling high-molecular-weight glutelin subunits of rye on the long arm of chromosome 1R
Authors: Singh N. K. , Shepherd K. W. 
Published: September 2009

SUMMARYThe gene(s) controlling the high-molecular-weight glutelin subunits in rye (designated asGlu-Rl) was mapped with respect to the centromere using a 1RL-1DS wheat-rye translocation line and sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Analysis of 479 seeds from test-crosses between a 1R/1RL-1DS heterozygote and the cultivar India 115, revealed 14·6% aneuploid and 3·95% recombinant progeny. Excluding the aneuploids, this locus was calculated to be 4·65 ± 1·04 cM from the centromere on the long arm of chromosome 1R, which is comparable to the position of the homoeologous loci in wheat and barley.
Inheritance of female mating propensities foryellowlocus genotypes inDrosophila melanogaster
Authors: Heisler I. Lorraine 
Published: September 2009

SUMMARYFemales from different wild-type laboratory populations ofDrosophila melanogasterdiffer genotypically in their degree of mating discrimination against mutantyellowmales. The chromosomal organization of this difference was examined in two wild-type laboratory strains by experimental observation of the mating propensities of hybrid females in a mass-mating, multiple choice situation. The results indicate that the strain difference is polygenic in origin, involving loci on both theX-chromosome and autosomes. Reciprocal crosses revealed no maternal/cytoplasmic effects. The mating scores of parental, F1and backcross females fit well to a model of additive chromosomal effects, withX-linked loci being recessive, and autosomal loci overdominant, for increased mating withyellowmales. However, interactions, arising most probably from recombination, led to increased mating withyellowon the part of F2females. In addition to the difference in female discrimination againstyellowmales, male/female interaction was found for the mating speed of flies from the two strains. These results are discussed in the light of previous studies of mating preferences inD. melanogaster. It is suggested that genetic variation in female mating preferences may be an important source of variation in the reported mating success of mutantyellowmales.
The genetics of tasting in mice: III. Quinine
Authors: Lush Ian E. 
Published: September 2009

SUMMARYTwenty-nine strains of mice were tested for their ability to taste a 0·8 mM solution of quinine sulphate. There were large strain differences, some strains (tasters) showing a strong aversion to the quinine and other strains (non-tasters) showing very little aversion. It was shown that the difference between strains 129/Sv and A2G is probably due to one gene. By using the CXB RI strains it was also shown that the difference between C57BL/6By and BALB/cBy is probably due to one gene. It is suggested that both differences may be due to the same gene, named Qui. In the progeny of a backcross involving both Soa and Qui there was evidence of an interaction between the genes which cannot be explained satisfactorily. Learning behaviour by the mice influenced their drinking habits, but this did not invalidate the results.
A presumed deletion covering theWandPhloci of the mouse
Authors: Lyon Mary F. , Glenister P. H. , Loutit J. F. , Evans E. P. , Peters J. 
Published: September 2009

SUMMARYA new allele at theW-locus (W19H), found in a mutagenesis experiment in which females were irradiated, involves a presumed deletion. The deletion covers thePhlocus (which forms part of a gene complex with theW,PhandRwloci), and the locus of a recessive lethal 2 cM distal toW. It does not extend distally to thebllocus; nor does it involve theRwlocus,W19H/Rwcompounds being viable and fertile. Thus, the length of the deletion is 2–7 cM. The non-involvement ofRwshows that, in the gene tripletRw,W,Ph,Rwmust lie proximal toWandPh, whose relative position remains unknown. Heteozygotes forW19Hare not anaemic, show only minimal white spotting and no pigment dilution; they thus resemble heterozygotes for the originalWmutant allele and differ fromW/Phtrans heterozygotes, which have extensive white spotting. In additionW19Hheterozygotes may be small and runted, many are believed to die prenatally, and some in the nest. Their radiosensitivity is increased. Homozygotes die at the pre-implantation stage.
Deleterious mutations as an evolutionary factor: 1. The advantage of recombination
Authors: Kondrashov Alexey S. 
Published: September 2009

SUMMARYA population withudeleterious mutations per genome per generation is considered in which only those individuals that carry less than a critical number ofkmutations are viable. It has been shown previously that under such conditions sexual reproduction is advantageous. Here we consider selection at a locus that determines recombination frequency of the whole genome. The valuev=u/ √khas been found to play the decisive role. Whenv< 0·35 the direction of selection for recombination may be different for different cases, but the intensity of selection is always very small. The advantage of recombination becomes considerable whenv> 0·5, its growth under increasingvbeing approximately linear. Ifv> 2 no less than 95% of the progeny are bound to die because of the selection against deleterious mutations. Since this seems to be too great a mutation load, we may assume 0·5 < v < 2·0 for any sexual population if mutation really maintains crossing-over. Results on selection at a locus which controls mutability provide evidence thatvis located within the specified interval if the physiological cost of a twofold reduction of the mutation rate is within the range 10–80%. A number of consequences of this hypothesis about the mechanism of selection for sex and recombination are discussed.
Genetic relationships between inbred strains of rats. An analysis based on genetic markers at 28 biochemical loci
Authors: Festing Michael F. W. , Bender Klaus 
Published: September 2009

SUMMARYGenetic similarities among 46 strains of rats based on published data involving 93 samples and 28 biochemical loci were assessed using principal coordinate and cluster analysis techniques. Seventeen strains were represented by more than one colony. In ten of these, nominally identical strains differed, and in four cases this was attributed to genetic contamination. A total of 52 genetically different strains were eventually identified. Strains BN and DA were most dissimilar, while strain BP was the most unusual strain over-all. The principal coordinate and cluster analysis showed three main clusters, which could be explained on the basis of linkage disequilibrium for some of the esterase loci in linkage group 5. Among six of these loci only 12 haplotypes were observed, with 24/52 strains having a single haplotype. Re-analysis of loci in linkage equilibrium failed to reveal any important clusters.
Genetic differences between two substrains of the inbred 101 mouse strain
Authors: West John D. , Peters Josephine , Lyon Mary F. 
Published: September 2009

SUMMARYTwo substrains of the inbred mouse strain 101, maintained at Harwell and at Neuherberg, and designated 101/H and 101/E1, differed at five of the eight genetic loci tested and it seems very likely that one of these substrains has been genetically contaminated. The available evidence suggests that 101/E1 is probably the contaminated substrain.
Sex ratio distortion in D. simulans after treatment with quinacrine
Authors: Tsakas S. C. , Lamnisou K. , Tsacas L. , David J. R. 
Published: September 2009

SummaryA significant excess of female offspring resulted when pregnant females of the D. simulans species were left to lay their eggs on food containing quinacrine. The same result occurred in a subsequent experiment in which male parents were injected with quinacrine. This was the first time that a chemical compound showing an affinity with DNA in vitro altered the sex ratio in a consistent manner. This effect had been predicted based on the unique quinacrine fluorescent staining pattern in D. simulans, in which only the Y stains intensely in mitotic chromosomes. It seems that treatment acts on spermatids or spermatozoa causing decreased functioning of the Y-bearing ones, resulting in an excess of female offspring. Interestingly, the species D. mauritiana and D. melanogaster, although very closely related to D. simulans, do not have its staining pattern and as predicted did not respond to treatment; therefore, the important parameter appears to be related to the staining pattern of mitotic chromosomes and not to the phylogenetic relationship.
Distorter genes of the mouset-complex impair male fertility when heterozygous
Authors: Lyon Mary F. 
Published: September 2009

SummaryMale mice heterozygous for two distorter genes,Tcd-1andTcd-2, of the mouset-complex but homozygous wild type for the responder, were generated by crossing animals carrying the partialt-haplotypesth51andth18to inbred strains. The fertility of these males was then compared with that of their brothers carrying normal chromosome 17s. On three of the inbred backgrounds used, C3H/HeH, C57BL/6J and TFH/H, theth51th18+ / + + + males were significantly less fertile than their normal sibs. With the fourth inbred strain used, SM/JH, both types of male were nonnally fertile. This confirmed earlier preliminary findings that when both homologues of chromosome 17 carry wild-type alleles of the responder, heterozygosity for the distorter genes is sufficient to impair fertility, but the effect varies with genetic background. These results are consistent with the concept that both the transmission ratio distortion and the male sterility caused by thet-complex are due to harmful effects of the distorter genes on wild-type alleles of the responder.
α-Amylase and β-amylase homoeoloci in species related to wheat
Authors: Ainsworth C. C. , Miller T. E. , Gale M. D. 
Published: September 2009

SummaryA study of α-amylase isozyme patterns from gibberellin-induced endosperms of wheat-alien genotypes (amphiploid, addition and substitution lines) resolved by flat-bed isoelectric focusing identified homoeoloci for α-Amy-1(malt α-AMY-1 genes) on chromosomes 6H ofHordeum vulgare, 6RL ofSecale cereale, 6RmofS. montanumand 6E ofAgropyron elongatum. Homoeoloci for α-Amy-2(green α-AMY-2 genes) were identified on chromosomes 7HchL ofHordeum chilense, 7RL ofSecale cereale, 7SbofAegilops bicornis, 7U ofAe. umbellulataand 7EL ofAgropyron elongatum. Analysis of mature grain β-amylase identified β-Amy-1loci on chromosomes 4H ofH.vulgare, 4HchofH. chilense, 4S1ofAe. sharonensisandAe. longissimaand β-Amy-2loci on chromosomes 5RL ofS. cerealeand 5U ofAe. umbellulata. These gene locations provide further evidence for the homoeology of the alien chromosomes with wheat and for the conservation of gene synteny among wheat and its relatives.
Caffeine-resistant mutants ofCaenorhabditis elegans
Authors: Hartman Philip S. 
Published: September 2009

SummaryWild-typeCaenorhabditis elegansfails to reach adulthood if L1 larvae are incubated in the presence of 30 mM or greater concentrations of caffeine. Eleven mutants have been isolated in which caffeine has a less pronounced effect on development. The mutations are recessive, define two genes, and have been mapped. The mechanism(s) of resistance is unknown.
Accumulation of mutations in sexual and asexual populations
Authors: Pamilo Pekka , Nei Masatoshi , Li Wen-Hsiung 
Published: September 2009

SummaryThe accumulation of beneficial and harmful mutations in a genome is studied by using analytical methods as well as computer simulation for different modes of reproduction. The modes of reproduction examined are biparental (bisexual, hermaphroditic), uniparental (selfing, automictic, asexual) and mixed (partial selfing, mixture of hermaphroditism and parthenogenesis). It is shown that the rates of accumulation of both beneficial and harmful mutations with weak selection depend on the within-population variance of the number of mutant genes per genome. Analytical formulae for this variance are derived for neutral mutant genes for hermaphroditic, selfing and asexual populations; the neutral variance is largest in a selfing population and smallest in an asexual population. Directional selection reduces the population variance in most cases, whereas recombination partially restores the reduced variance. Therefore, biparental organisms accumulate beneficial mutations at the highest rate and harmful mutations at the lowest rate. Selfing organisms are intermediate between biparental and asexual organisms. Even a limited amount of outcrossing in largely selfing and parthenogenetic organisms markedly affects the accumulation rates. The accumulation of mutations is likely to affect the mean population fitness only in long-term evolution.
Adaptive landscapes, genetic distance and the evolution of quantitative characters
Authors: Barton N. H. , Turelli Michael 
Published: September 2009

SummaryThe maintenance of polygenic variability by a balance between mutation and stabilizing selection has been analysed using two approximations: the ‘Gaussian’ and the ‘house of cards’. These lead to qualitatively different relationships between the equilibrium genetic variance and the parameters describing selection and mutation. Here we generalize these approximations to describe the dynamics of genetic means and variances under arbitrary patterns of selection and mutation. We incorporate genetic drift into the same mathematical framework.The effects of frequency-independent selection and genetic drift can be determined from the gradient of log mean fitness and a covariance matrix that depends on genotype frequencies. These equations describe an ‘adaptive landscape’, with a natural metric of genetic distance set by the covariance matrix. From this representation we can change coordinates to derive equations describing the dynamics of an additive polygenic character in terms of the moments (means, variances, …) of allelic effects at individual loci. Only under certain simplifying conditions, such as those derived from the Gaussian and house-of-cards approximations, do these general recursions lead to tractable equations for the first few phenotypic moments. The alternative approximations differ in the constraints they impose on the distributions of allelic effects at individual loci. The Gaussian-based prediction that evolution of the phenotypic mean does not change the genetic variance is shown to be a consequence of the assumption that the allelic distributions are never skewed. We present both analytical and numerical results delimiting the parameter values consistent with our approximations.
Antisuppressor mutations inAspergillus nidulans: cold-resistant revertants of suppressorsuaC109
Authors: Martinelli S. D. 
Published: September 2009

SummaryCold-resistant revertants of the cold-sensitive, ribosomal suppressorsuaC109have been isolated, with a view to obtaining mutations in new ribosomal protein genes. Many revertants had reduced suppressor activity and were classified as antisuppressor mutants. Both intragenic and extragenic reversions were found. In seven strains the extragenic reversion to cold resistance segregated with the antisuppressor phenotype, and these were designatedasumutations. Three of the fiveasugenes, C, B and D were mapped to linkage groups, I, II and V respectively. The antisuppressors are not gene-specific, although they mainly antagonize the activity of ribosomal suppressors. The antisuppressors altered all aspects of the phenotype of suppressorsuaC109including sensitivity to aminoglycoside antibiotics, and are therefore thought to be mutations in ribosomal protein genes.
Inheritance of alleles at ten enzymatic loci of the freshwater snail Stagnicola elodes (Basommatophora: Lymnaeidae)
Authors: Rudolph Paul H. , Burch J. B. 
Published: September 2009

SummaryThe inheritance of alleles at ten enzyme loci of Stagnicola elodes (Lymnaeidae) was analysed by laboratory crosses. Alleles for alanine aminopeptidase (2 alleles), leucine aminopeptidase (2 alleles), aspartate aminotransferase (2 alleles), β-hydroxybutyrate dehydrogenase-1 (4 alleles), 6-phosphogluconate dehydrogenase (2 alleles), esterase-2 (2 alleles), esterase-3 (2 alleles), esterase-7 (2 alleles), esterase-13 (2 alleles) and esterase-18 (2 alleles) segregate in the F2 generation according to Mendelian expectations. Contingency X2 tests for linkage done on F2 progeny from crosses between strains homozygous for alternate alleles at two loci showed that β-hydroxybutyrate dehydrogenase-1, esterase-13 and esterase-18 are presumably linked.
A gene location for the inheritance of the Cataract Fraser (CatFr) mouse congenital cataract
Authors: Muggleton-Harris A. L. , Festing M. F. W. , Hall M. 
Published: September 2009

SummaryAnimal models which emulate defects similar to those in man are required for medical research. Many investigations on the cellular, developmental and molecular aspects of cataractogenesis use the cataract Fraser (CatFr) mouse. This report shows that the CatFT and Lop lens abnormalities are linked, and are probably allelic genes on chromosome 10. It also shows that the CatFT gene is maintained on an inbred genetic background which differs from 79 other strains; it is proposed that this strain be named CAT.