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the effects of anthranilic acid on gene expression.1. a drosophila pseudoobscura amylase gene cloned in escherichia coli is expressed at high levels. the expression of this gene is repressed when glucose (0.5% final concentration) is added to a starch minimal medium culture of e. coli cells containing the amylase plasmid. 2. addition of anthranilic acid (5 and 7 mm final exogenous concentration) to catabolite repressed cells mimics the action of adenosine 3'5' cyclic monophosphate (camp) by depressing the expression of the amylase. 3. the result ...19901691993
molecular analysis of evolutionary changes in the expression of drosophila esterases.drosophila melanogaster transformed with the esterase 5 (est-5) gene from drosophila pseudoobscura were used to assess the evolutionary basis for differences in the sex- and tissue-specific expression of the esterase 5 (est 5) enzyme in d. pseudoobscura relative to its homologue in d. melanogaster, est 6. est 5 is expressed in the eyes and hemolymph of transformed d. melanogaster just as it is in d. pseudoobscura, but it is not detectable in the ejaculatory duct, where the homologous enzyme, est ...19901700427
dna sequence evolution of the amylase multigene family in drosophila pseudoobscura.the alpha-amylase locus in drosophila pseudoobscura is a multigene family of one, two or three copies on the third chromosome. the nucleotide sequences of the three amylase genes from a single chromosome of d. pseudoobscura are presented. the three amylase genes differ at about 0.5% of their nucleotides. each gene has a putative intron of 71 (amy1) or 81 (amy2 and amy3) bp. in contrast, drosophila melanogaster amylase genes do not have an intron. the functional amy1 gene of d. pseudoobscura diff ...19901699840
mitochondrial dna evolution in the obscura species subgroup of drosophila.mitochondrial dna (mtdna) restriction site maps for nine species of the drosophila obscura subgroup and for drosophila melanogaster were established. taking into account all restriction enzymes (12) and strains (45) analyzed, a total of 105 different sites were detected, which corresponds to a sample of 3.49% of the mtdna genome. based on nucleotide divergences, two phylogenetic trees were constructed assuming either constant or variable rates of evolution. both methods led to the same relations ...19902120450
amylase gene expression in intraspecific and interspecific somatic transformants of drosophila.the amylase locus in drosophila melanogaster normally contains two copies of the structural gene for alpha-amylase, a centromere-proximal copy, amy-p, and a distal copy, amy-d. products of the two genes may display discrete electrophoretic mobilities, but many strains known to carry the amy duplication are characterized by a single amylase electromorph, e.g., oregon-r, which produces the mobility variant amy-1. a transient expression assay was used in somatic transformation experiments to test t ...19901699842
p-transposable vectors expressing a constitutive and thermoinducible hsp82-neo fusion gene for drosophila germline transformation and tissue-culture transfection.three p-transposable vectors (approx. 16, 12, and 9 kb) were constructed containing a hsp82-neo fusion gene encoding a truncated heat-shock protein 82 of drosophila pseudoobscura and the bacterial neomycin phosphotransferase (npt). in transgenic drosophila melanogaster, hsp82-neo exhibits high levels of housekeeping gene promoter and npt activities in all cells in the absence of heat-shock and is further induced (fivefold) by elevated temperatures (35 degrees-36 degrees c). the hsp82-neo selecti ...19902165019
conservatism of sites of trna loci among the linkage groups of several drosophila species.the sites of seven trna genes (arg-2, lys-2, ser-2b, ser-7, thr-3, thr-4, val-3b) were studied by in situ hybridization. 125i-labeled trna probes from drosophila melanogaster were hybridized to spreads of polytene chromosomes prepared from four drosophila species representing different evolutionary lineages (d. melanogaster, drosophila hydei, drosophila pseudoobscura, and drosophila virilis). most trna loci occurred on homologous chromosomal elements of all four species. in some cases the number ...19902107332
localization of genes causing postzygotic isolation in two hybridizations involving drosophila pseudoobscura.the genes causing postzygotic isolation in two drosophila hybridizations were localized to regions of the x chromosome. the x has a large effect on d. pseudoobscura pseudoobscura ("u.s.a.")-d. pseudoobscura bogotana ("bogota") hybrid male sterility. recombination analysis shows that this effect is due entirely to a small chromosome region representing less than 20 per cent of the x. this result suggests that a single x-linked gene may be involved. a maximum likelihood mapping procedure places th ...19892807977
selection in natural and experimental populations of drosophila pseudoobscura.the inverted gene arrangements of drosophila pseudoobscura were used by th. dobzhansky in pioneering analyses of natural selection. recent experiments have shed light on the mechanisms of selection contributing to the balanced polymorphism for the gene arrangements. in experimental populations, both major components of fitness, viability and fertility, are frequency dependent, and rare genotypes often have a selective advantage. viabilities are also density dependent. the frequency dependence an ...19892687095
nucleotide sequence of the xdh region in drosophila pseudoobscura and an analysis of the evolution of synonymous codons.the nucleotide sequence of the xdh region of drosophila pseudoobscura is presented. the xdh gene structure and organization are compared with the homologous region in d. melanogaster. this locus is shown to have similar organization in the two species, although an additional intron and three insertion/deletion events are described for the d. pseudoobscura coding region. the encoded proteins are predicted to have very similar charges and hydrophobic/hydrophilic domains even though 11% of the amin ...19892493563
reproductive isolation as a consequence of adaptive divergence in drosophila pseudoobscura. 198928564510
laboratory evolution of epicuticular hydrocarbon composition and cuticular permeability in drosophila pseudoobscura: effects on sexual dimorphism and thermal-acclimation ability. 198928568563
interspecific comparison of the period gene of drosophila reveals large blocks of non-conserved coding dna.we have cloned and sequenced the coding region of the period (per) gene from drosophila pseudoobscura and d. virilis. a comparison with that of d. melanogaster reveals that the conceptual translation products consist of interspersed blocks of conserved and non-conserved amino acid sequence. the non-conserved portion, comprising approximately 33% of the protein sequence, includes the perfect thr-gly repeat of d. melanogaster, which is absent from the d. pseudoobscura and d. virilis proteins. base ...19883208754
rare male mating advantage in a natural population of drosophila pseudoobscura.the natural selection acting on chromosomal inversions was studied in a natural population of drosophila pseudoobscura. females from this population were allowed to produce offspring from their matings in nature. they were then remated to males from a laboratory strain and again allowed to produce offspring. offspring were also produced from matings of males from nature to laboratory females. diagnosis of salivary chromosomes in these several sets of larval offspring allowed us to deduce the kar ...19883200863
evidence for non-neutrality of mitochondrial dna haplotypes in drosophila pseudoobscura.mitochondrial dna (mtdna) haplotypes usually are assumed to be neutral, unselected markers of evolving female lineages. this assumption was tested by monitoring haplotype frequencies in 12 experimental populations of drosophila pseudoobscura which were polymorphic for mtdna haplotypes. populations were maintained for at least 10 generations, and in one case for 32 generations, while tests of mtdna selective neutrality were conducted. in an initial population, formed from a mixture of two strains ...19883197957
the effects of inbreeding and ventilation on mating behavior in drosophila pseudoobscura.two outbred and two inbred lines of drosophila pseudoobscura were used in mating behavior studies. for each line, mating rates were compared under both ventilated and nonventilated conditions. under nonventilated conditions courtship and mating were earlier, not following a random rate of occurence, and females mated after fewer courtships. flies from inbred lines tended to court and mate earlier. under all conditions a high proportion of matings occured on the first courtship attempt.198724925652
modifier genes of the sex ratio trait in drosophila pseudoobscura.the msr trait of drosophila pseudoobscura occurs when "sex-ratio" males produce a very high frequency of null-x sperm which give rise to sterile male (x/o) progeny. the trait involves dramatically lowered fecundity due to spermiogenic failure. the msr trait is multigenic and the genes are located on autosomes ii, iii and iv of the l116 laboratory stock. this stock also carries genes on the y chromosome that lower the level of msr. when the genes on the l116 autosomes are present together or with ...198717246384
genetic divergence under uniform selection. iii. selection for knockdown resistance to ethanol in drosophila pseudoobscura populations and their replicate lines.replicate d. pseudoobscura lines from populations collected at different geographic locations were selected for increased knockdown resistance to ethanol. population background affected the initial rate of response but not the extent that lines responded. lines were tested for physiological traits contributing to increased knockdown resistance. populations showed different correlated responses for two traits (tolerance of ethanol, and of acetone), suggesting that they had responded to selection ...19873597126
restriction-map variation in the alcohol dehydrogenase region of drosophila pseudoobscura.a 32-kb region including the adh structural gene was analyzed with six restriction endonucleases in 20 lines of drosophila pseudoobscura, one line of d. persimilis, and one line of d. miranda. nineteen lines of d. pseudoobscura from a single population were estimated to be polymorphic at one in every 15 nucleotides (p = 0.066). any two homologous chromosomes chosen at random were heterozygous at one in 48 (h = 0.021) nucleotides. two small insertions of 50 and 200 bp were found approximately 7 k ...19872833670
conserved arrangement of nested genes at the drosophila gart locus.the drosophila melanogaster gart gene encodes three enzymatic activities in the pathway for purine de novo synthesis. alternative processing of the primary transcript leads to the synthesis of two overlapping polypeptides. the coding sequence for both polypeptides is interrupted by an intron that contains a functional cuticle protein gene encoded on the opposite dna strand. here we show that this nested organization also exists at the homologous locus of a distantly related species, drosophila p ...19873123310
a comprehensive study of genic variation in natural populations of drosophila melanogaster. i. estimates of gene flow from rare alleles.in order to assess the evolutionary significance of molecular variation in natural populations of drosophila melanogaster, we have started a comprehensive genetic variation study program employing a relatively large number of gene-protein loci and an array of populations obtained from various geographic locations throughout the world. in this first report we provide estimates of gene flow based on the spatial distributions of rare alleles at 117 gene loci in 15 worldwide populations of d. melano ...198717246368
historical effective size and the level of genetic diversity in drosophila melanogaster and drosophila pseudoobscura.we report the results of a sequential gel electrophoretic study of protein variation in drosophila melanogaster and its comparison with d. pseudoobscura. the number of alleles and mean heterozygosity were lower in d. melanogaster than in d. pseudoobscura. on the other hand, geographical populations of drosophila melanogaster have been shown to be much more differentiated than those of d. pseudoobscura. the results suggest that in d. melanogaster low-frequency alleles have been lost during the co ...19873107543
an amylase gene from drosophila pseudoobscura is expressed in escherichia coli. functional selection and biochemical comparisons of the fly- and clone-produced amylases.an amylase gene from drosophila pseudoobscura was isolated from a genomic library constructed in pbr322 and cloned in escherichia coli by selecting for the ability of its product to hydrolyze starch, a carbon source not normally utilized by e. coli. hybridization of pamy17f to d. pseudoobscura polytene chromosomes shows a positive signal at the amylase pseudogene locus (bank 78, chromosome 3). the chimeric plasmid pamy17f, has been altered in such a way as to increase amylase expression. souther ...19872443177
viabilities of amylase genotypes in drosophila pseudoobscura on starch and maltose food.in order to study the relationship between selection on an enzyme and the environment, viability was measured for genotypes at the α-amylase (amy) locus of d. pseudoobscura on food containing either starch as the primary source of carbohydrates or, as a control, maltose, the breakdown product of starch by amylase. these conditions were chosen to reveal possible differences among these genotypes in their abilities to survive on starch food. counted numbers of larvae were cultured on food with low ...198728563764
genetic variation for dispersal by drosophila pseudoobscura and drosophila persimilis.release-recapture experiments using drosophila pseudoobscura and d. persimilis strains of different karyotypes were performed in a heterogeneous environment. the heterogeneity was due to both spatial variation and the species of yeast used to attract the released flies. no karyotypic-specific habitat preferences were detected. however, in all releases, different strains did behave differently with respect to one or both of the heterogeneous factors. these results indicate there is variation for ...198617246313
an investigation of the genetics of "male sex-ratio" phenotype in drosophila pseudoobscura.a laboratory strain of drosophila pseudoobscura (l116) is studied that, when crossed to sex-ratio homozygous females, produces sons that exhibit varying levels of the male sex-ratio (msr) phenotype. the msr phenotype occurs only in sex-ratio males and is due to the production of a high frequency of nullo-xy sperm. the level of the msr phenotype is variable, and new variability is generated in one father-son transmission. pedigree studies indicate the genes for msr reside on the y chromosome or t ...198617246330
laboratory-induced changes in the mate recognition system of drosophila pseudoobscura. 19863718418
habitat choice by drosophila pseudoobscura: the roles of genotype and of experience. 19863718416
natural selection vs. random drift: evidence from temporal variation in allele frequencies in nature.we have obtained monthly samples of two species, drosophila pseudoobscura and drosophila persimilis, in a natural population from napa county, california. in each species, about 300 genes have been assayed by electrophoresis for each of seven enzyme loci in each monthly sample from march 1972 to june 1975. using statistical methods developed for the purpose, we have examined whether the allele frequencies at different loci vary in a correlated fashion. the methods used do not detect natural sele ...19854054608
mitochondrial dna variation in drosophila pseudoobscura and related species in pacific northwest populations.we have analysed mitochondrial dna (mtdna) from pacific northwest populations of drosophila pseudoobscura, d. persimilis, and d. miranda using six restriction enzymes. we find that hpaii restriction sites are hypervariable compared to the other enzymes used. this hypervariability allows construction of a maximum parsimony map linking each mtdna genotype. small insertions, possibly tandem duplications, appear to have arisen concomitantly with, or subsequent to, speciation events, perhaps within t ...19853880378
nearly identical allelic distributions of xanthine dehydrogenase in two populations of drosophila pseudoobscura.in a previous study, keith (1983) showed by sequential gel electrophoresis of the esterase-5 protein in drosophila pseudoobscura that a highly polymorphic locus with many alleles can have very similar frequency distributions in populations separated by 500 km. the present work studies another highly polymorphic locus, xanthine dehydrogenase, in the same california population samples, using the same technique to distinguish allelic classes. twelve electromorphs were found in one population and 15 ...19853871004
chromosomal and behavioral studies of mexican drosophila. iii. inversion polymorphism of d. pseudoobscura.four new gene arrangements of chromosome 3 of drosophila pseudoobscura are reported, as well as an updated phylogenetic sequence of the inversion polymorphism in this species. evidence that the tree line gene arrangement of chromosome 3 was the original form in d. pseudoobscura, and that central mexico is the center of distribution of this species is discussed.19854031462
studies on the pathogenicity of spiroplasmas for drosophila pseudoobscura.representatives of several currently available spiroplasma serovars were used in feeding and injection experiments involving drosophila pseudoobscura adult flies in order to evaluate the host-range of the spiroplasmas and to determine their pathogenicity for flies. many of the isolates injected into flies either do not survive or grow poorly, and have no negative effects on longevity or fecundity. two spiroplasma strains, honey-bee (serovar i-2) and cornstunt (serovar i-3), can grow to high titr ...19846712059
a test for rare male mating advantage with drosophila pseudoobscura karyotypes.recent work has called into question the reality of the rare male mating advantage, pointing out that it could be a statistical artifact of marking flies for behavioral observation or of experimental bias in collecting males. we designed an experiment to test for rare male mating advantage that avoids these sources of bias. large numbers of males of three drosophila pseudoobscura karyotypes were allowed to mate with females of one karyotype in population cages. the females were then isolated bef ...198417246224
a note on barometric pressure and behavior in drosophila pseudoobscura. 19846487232
population genetics of drosophila amylase. v. genetic background and selection on different carbohydrates.frequency changes in amylase allozymes and patterns of tissue-specific expression of amylase have been monitored in laboratory populations of drosophila pseudoobscura maintained on media in which the only carbohydrate source was maltose or starch. nonrandom changes occurred in patterns of expression, whereas no patterns in allozyme frequency changes were discernible. the nature of the pattern changes was similar to an identical study done on populations derived from a natural population several ...198417246202
mitochondrial gene flow.to account for the transmission of mitochondrial dna between conspecific species drosophila pseudoobscura and d. persimilis in sympatry reported by j.r. powell [powell, j.r. (1983) proc. natl. acad. sci. usa 80, 492-495], a simple model of gene flow and selection in infinite populations is analyzed. the model assumes two alleles at each of two loci, one of which is coded by an autosome and the other by mitochondrial dna. viability selection is presumed to be underdominant--i.e., heterozygous inf ...19846584909
sperm predominance among drosophila pseudoobscura karyotypes. 198428555808
multiple mating and female fitness in drosophila pseudoobscura. 198328568127
resource partitioning among genotypes of drosophila pseudoobscura. 198328568031
population genetics of drosophila amylase. iv. selection in laboratory populations maintained on different carbohydrates.two polymorphic systems impinging on alpha-amylase in drosophila pseudoobscura have been studied in laboratory populations maintained on medium in which the only carbohydrate source was starch (the substrate of amylase) and replicas maintained on medium in which the only carbohydrate source was maltose (the product of amylase). the two polymorphic systems were alleles at the structural gene (amy) coding for the enzyme (allozymes) and variation in the tissue-specific expression along the adult mi ...19836189764
interspecific cytoplasmic gene flow in the absence of nuclear gene flow: evidence from drosophila.mtdna polymorphism has been studied by restriction endonuclease site variation in drosophila pseudoobscura and its sibling species d. persimilis. eight enzymes have been used to study 54 isofemale strains from areas where the two species are sympatric and d. pseudoobscura is allopatric. where sympatric, 75-80% of the strains have mitochondrial genomes found in both species. where allopatric, d. pseudoobscura has diverged to the point where none of the strains have mtdna in common with d. persimi ...19836300849
chromatin structure and transcriptional activity of an x-linked heat shock gene in drosophila pseudoobscura.nuclease digestion of isolated nuclei was used to test whether differential chromatin structure exists for a dosage-compensated heat shock gene in drosophila pseudoobscura. no differences were observed in nuclease sensitivity at this locus in males and females, either under heat shock or non-heat shock conditions, using micrococcal nuclease or dnase i. although the higher level of nuclease sensitivity characterized by the induced state was removed when nuclei were prepared in high salt (0.45 m s ...19836315715
virility deficiency and the sex-ratio trait in drosophila pseudoobscura. ii. multiple mating and overall virility selection.previous studies on fitness components of drosophila have shown the over-whelming importance of virility selection. in this study, virility selection is further partitioned into two components-one with respect to virgin females and the other with respect to nonvirgin females. the relative importance of the two components to the overall virility selection depends on the remating tendency of females which is investigated here. a theoretical model is then proposed to estimate virility selection und ...198317246171
virility deficiency and the sex-ratio trait in drosophila pseudoobscura. i. sperm displacement and sexual selection.the sex-ratio (sr) phenomenon is associated with the x chromosome of many species of drosophila. males carrying sr transmit predominantly sperm bearing the x chromosome. sr, therefore, has a very significant advantage in segregation. this paper provides an experimental analysis of the role of virility selection in preventing the fixation of sr. sr males are found to suffer substantial virility reduction when mated with nonvirgin females but not with virgin females. the reduced virility arises be ...198317246170
selection for light preference during ovipositing in drosophila pseudoobscura.selection was carried out on a population of drosophila pseudoobscura to obtain lines preferring high-light intensity or low-light intensity during oviposition. this species is generally characterized as preferring low-light intensities. it was possible to select for increased preference for high-light intensity, but not for low-light intensity during oviposition. however, additive genetic variability exists in preferences for both high- and low-light intensities. the original population was pro ...19836652564
evidence for extensive genetic differentiation between the sex-ratio and the standard arrangement of drosophila pseudoobscura and d. persimilis and identification of hybrid sterility factors.this study deals with sex-ratio genes tightly linked within the sex-ratio inversion. by taking advantage of the fact that the sex-ratio chromosome of drosophila persimilis [sr(b)] is homosequential to the standard chromosome of d. pseudoobscura [st(a)], we carried out two reciprocal introgression experiments. individual segments of sr(b) or st(a) were introgressed into the genome of d. pseudoobscura or d. persimilis, respectively. males possessing a hybrid sr(b)-st(a) x chromosome and a genetic ...198317246158
frequency distribution of esterase-5 alleles in two populations of drosophila pseudoobscura.statistical tests comparing allele frequencies in natural populations with those predicted by various theories of genic variation depend critically on the accurate enumeration of alleles. this study used a series of five sequential electrophoretic conditions to characterize the allele frequency distributions of esterase-5 in two large population samples of drosophila pseudoobscura from california. in standard chromosome lines 12 electromorphs were discriminated using a single electrophoretic con ...198317246152
population genetics in the american tropics : 18. the genetic structure of peripheral drosophila pseudoobscura from colombia.there are several colombian populations of drosophila pseudoobscura which have begun to show divergence. the temporal samples of torobarroso, one of the local populations identified, demonstrate genetic "resourcefulness" and selective opportunism by fluctuating mortality. the data suggest that both balanced selection and mutational origin are necessary to account for the frequencies of drastic genes encountered. in genetic isolates there seems to exist alternatively a mutational component and a ...198324263539
tissue localization of esterase-5 in drosophila pseudoobscura.disc gel electrophoresis of dissected adults of drosophila pseudoobscura showed that most of the esterase-5 activity was in the head (36%) and thorax (51%), with little activity in the abdomen (13%). no activity was found in digestive tissues, reproductive tissues, or nervous tissues. most of the est-5 activity (61%) was found to be associated with hemolymph. however, the eyes contained 39% of the total est-5 activity. these results were supported by spectrophotometric assays of esterase activit ...19836870773
the isolation of biological rhythm mutations on the autosomes of drosophila melanogaster.a selection for autosomal circadian rhythm variants in drosophila melanogaster resulted in the isolation of 3 new mutants, all of which display an abnormal synchronization of daily rhythms to entraining environmental cycles. in populations of phase-angle-2 (psi-2) and phase-angle-3 (psi-3) mutants, daily peaks of adult emergence are hours earlier than normal when the strains are entrained to cycles of either light and dark or high and low temperature. like an early-emerging strain previously iso ...19836443122
genic variation in abundant soluble proteins of drosophila melanogaster and drosophila pseudoobscura.genic variation was surveyed for 20 proteins of drosophila melanogaster and 18 proteins of d. pseudoobscura. analysis was by extraction and one-dimensional polyacrylamide gel electrophoresis under nondenaturing conditions, followed by staining with coomassie brilliant blue to detect soluble proteins present in relatively large amounts ("abundant soluble proteins"). d. melanogaster was polymorphic for 65% of its protein loci and an individual was heterozygous for 10% of its loci. the respective f ...19827173605
an experimental study of neutrality at the malic dehydrogenase and esterase-5 loci in drosophila pseudoobscura. 19827085337
a study of reaction norms in natural populations of drosophila pseudoobscura. 198228567833
"sex-ratio" trait, sex composition, and relative abundance in drosophila pseudoobscura. 198228581105
using frequency distributions to detect selection: inversion polymorphisms in drosophila pseudoobscura. 198128563401
multiple mating and the "sex-ratio" trait in drosophila pseudoobscura. 198128563371
components of maze running in drosophila pseudoobscura dn drosophila persimilis. 19817325947
gene flow and the geographical distribution of a molecular polymorphism in drosophila pseudoobscura.this paper discusses the relation between the geographical distribution of an enzyme polymorphism and population structure in drosophila pseudoobscura. california populations of this species living in very different montane and lowland habitats separated by several kilometers are similar to each other in the frequency of an esterase allele. previous estimates suggest that gene flow is too limited to account for this homogeneity of genetic structure, so that it must reflect some balancing force o ...19817338302
a critical examination of the dual system theory in ostrinia nubilalis.beck's dual system theory (dst) is examined theoretically and experimentally by investigating the oviposition rhythm of ostrinia nubilalis and its entrainment by light cycles. several well-known circadian phenomena are not accounted for by the dst. 1) it does not generate transient cycles when light pulses fall during the advance portion of the circadian cycle. this is also reflected in dst-predicted phase-response curves (prc's) for both drosophila pseudoobscura and o. nubilalis. steady-state p ...19817304776
variation in biochemical properties of allozymes of xanthine dehydrogenase in drosophila pseudoobscura.twenty-six d. pseudoobscura strains isogenic for xanthine dehydrogenase alleles from mesa verde, colorado, were tested for differences in the biochemical properties of different allelic forms of xanthine dehydrogenase. no significant differences in binding affinity (km) or substrate specificity of the enzyme were found. significant variation among strains, in activity (vmax) and among electromorphs, as well as among strains, in thermolability was found. for the few strains tested, the activity a ...19806943118
photobehavioral differentiation in natural populations of drosophila: changes of photoresponse over time in drosophila pseudoobscura and drosophila persimilis.the photobehavior of a sympatric assemblage of drosophila pseudoobscura and d. persimilis from california was examined over a 13-month period. during that time, certain aspects of the behavior remained constant (e.g., the mean resting photoresponse), while other aspects changed (e.g., the level of genotypic variation of the resting photoresponse of d. persimilis). the data support the contention of rockwell et al. [rockwell, r. f., cooke, f., and harmsen, r. (1975). behav. genet. 5:189-202] that ...19807469972
activity variants of acid phosphatase-3 among chromosome 3 inversions of drosophila pseudoobscura.allozymes of the ap-3 locus in drosophila pseudoobscura show very strong associations with chromosome 3 inversions. the 0.98 electrophoretic allele is associated with the tl, sc, ch and pp gene arrangements, while the 1.00 electrophoretic allele is characteristic of the ar and st gene arrangements. variation in relative 0.98 and 1.00 ap-3 allozyme activities of chromosome 3 isogenic strains was examined on acrylamide gels in f1 heterozygotes obtained by crossing these strains individually to a r ...19807262544
distinctions among allelic variants associated with chromosome 3 inversions in drosophila pseudoobscura and drosophila persimilis.efforts were made to discriminate new genetic variants among electrophoretic alleles that are associated with chromosome 3 inversions of drosophila pseudoobscura and d. persimilis. apparent genetic similarities for electrophoretic alleles between these two species and among the common inversions they carry were reexamined by altering gel concentration and buffer ph. at the amylase locus, the 1.09 electrophoretic allele could be further separated into two allelic classes that differentiated the w ...19806167488
clan lethals and inter-year allelism in death valley drosophila pseudoobscura.a chromosome 2 lethal allelism rate of about 3% found in the 1974 population of d. pseudoobscura in death valley, california. this rate was significantly higher than allelism rates in other southern california populations. the death valley population was sampled again in 1975 and 1977, with allelism rates of 1% and 0.5%, respectively. in 1974, several lethals were in high frequencies (about 1%), a pattern that reappeared in 1975 and 1977. however, none of the lethals in high frequency one year w ...19807203006
variation in activities of amylase allozymes associated with chromosome inversions in drosophila pseudoobscura, d. persimilis and d. miranda.different electrophoretic alleles of amylase show associations with particular chromosome 3 inversions in d. pseudoobscura and d. persimilis. relative adult amylase activities were compared in 37, 37 and 10 strains of d. pseudoobscura, d. persimilis and d. miranda, respectively. strains carrying the same electrophoretic allele were compared by crossing these lines individually to a reference strain carrying a different electrophoretic mobility allele. this procedure allows comparisons among spec ...19806159250
composite stepwise mutation model under the neutral mutation hypothesis.as an extension of the conventional ("ohta-kimura") stepwise mutation model, a new model is proposed. in this model, it is assumed that each charge state ("electromorph") is represented by k alleles and that a mutation changes an allele either by one step in the charge space or to one of the other members of the identical electromorph. it is shown that the net genetic variability within a population is similar to that predicted by the infinite-allele model ("kimura-crow" model) rather than to th ...19806928979
experimental and theoretical analysis of the "sex-ratio" polymorphism in drosophila pseudoobscura.the sex-ratio chromosome (sr) is a widespread, multiply inverted rearrangement of the x chromosome present in several species of drosophila. male carriers transmit mostly x-bearing sperm. in the absence of strong counteracting selection, sr is expected to increase rapidly to fixation, causing extinction. the present study incorporates a selection-components analysis of sr in laboratory populations, using the closely linked esterase-5 locus as a marker. estimated fitnesses show directional viabil ...198017249004
apparent absence of a separate beta-oscillator in phasing the circadian rhythm of eclosion in drosophila pseudoobscura. 19807458798
dosage compensation of x-linked heat-shock puffs in drosophila pseudoobscura.four major puffs are inducible by heat shock in the larval salivary gland chromosomes of d. pseudoobscura. two of these puffs are present at 23 and 39-40 on the right arm of the x chromosome and two are present at 53 and 58 on chromosome 2. by means of in situ hybridization, residual homologies were demonstrated between the puffs at 23 in d. pseudoobscura and at 63 c in d. melanogaster, and between the two chromosome 2 puffs of d. pseudoobscura and 87a and 87c of d. melanogaster. rna synthesis w ...19806155244
r- and k-selection in drosophila pseudoobscura. 198028568469
frequency-dependent mating in a modified allozyme locus of drosophila pseudoobscura. 197928563948
population genetics of mexican drosophila vi. cytogenetic aspects of the inversion polymorphism in drosophila pseudoobscura. 197928568185
gene flow and life history patterns.dispersal distances overestimate the gene-flow scale l (the square-root of the mean squared distance travelled from birth to reproduction) when egg laying is concentrated early in dispersal and when there is mortality during dispersal. if egg laying follows a square-root normal distribution in time, as it does in several drosophila species, then l is reduced to about 0.6 of that estimated from dispersal alone, unless egg laying is concentrated in a very brief period. if mortality is such that th ...197917248966
frequency-dependent selection at the pgm-1 locus of drosophila pseudoobscura.frequency-dependent fitness was studied at the pgm-1 locus of drosophila pseudoobscura with respect to two fitness components: rate of development and larva-to-adult survival. the pgm-1 locus is very polymorphic with only two alleles, pgm-1(100) and pgm-1(104), occurring at high frequencies. for each of these two alleles, 20 homozygous strains were obtained from a sample of 1,140 wild-inseminated females. first-instar larvae of the two genotypes were combined in a set of eight different frequenc ...1979161241
population genetics of drosophila amylase. ii. geographic patterns in d. pseudoobscura.morph frequencies of three related polymorphisms were determined in ten natural populations of drosophila pseudoobscura. they are the well-known inversion polymorphism of the third chromosome and the polymorphism for alpha-amylase produced by the structural gene amy (which resides on the third chromosome). the third polymorphism was for tissue-specific expression of amy in adult midguts; a total of 13 different patterns of activity have been observed. the preceding paper (powell and lichtenfels ...1979488707
population genetics of drosophila amylase. i. genetic control of tissue-specific expression in d. pseudoobscura.drosophila pseudoobscura is polymorphic for tissue-specific expression of alpha-amylase in adult midguts. this enzyme is encoded by a single locus, amy, on the third chromosome. in this paper we show: (1) up to about 12 days post-eclosion, the midgut activity patterns remain stable; after 12 days areas not showing activity previously begin to show activity. thus, the genes controlling the expression of amy are temporally acting. (2) diet affects the quantitative, but not the qualitative, express ...1979488706
evidence for selection by male mating success in natural populations of drosophila pseudoobscura.gene arrangement frequencies were determined at two stages in the life history of drosophila pseudoobscura taken from nature. three populations in the central highlands of mexico were each sampled twice during 1976. gene arrangement frequencies were measured in adult males and in larvae that were the offspring of females collected at the same time. the adult males were in all likelihood a representative sample of those who fathered the larvae produced by the wild females. differences in gene arr ...1979286338
extent of genetic variation at a highly polymorphic esterase locus in drosophila pseudoobscura.the esterase-5 locus of drosophila pseudoobscura has been screened for variation by using a wide variety of electrophoretic conditions and by testing heat sensitivity. among 50 isogenic lines from 17 populations, 21 genetic variants were found at the locus, 18 by electrophoresis and 3 by heat denaturation. including alleles previously known, there are a total of 30 alleles at this locus in natural populations. this represents a doubling of the previous estimates of polymorphism at this locus. th ...1978283418
study of the charge-state model for electrophoretic variation using isoelectric focusing of esterase-5 from drosophila pseudoobscura. 1978683345
response to selection for mating speed and changes in gene arrangement frequencies in descendants from a single population of drosophila pseudoobscura.heritability estimates, based on 19 generations of selection for fast and slow mating speed, were not significantly different from zero at the 0.05 level in any replicate of selected lines in a population of flies descended from the mather population in california. only the combined heritability estimate of approximately 2% was significant. this indicated that very little additive genetic variance was present in the base population and that strong directional selection for rapid mating may have ...197817248849
modifiers and "sex ratio" in drosophila pseudoobscura. 197828567934
mating pattern and mating success of drosophila pseudoobscura karyotypes in large experimental populations. 197828563737
positive and negative geotaxis: sex-linked traits in drosophila pseudoobscura.using a hirsch classification maze, selection was made for positive and negative geotactic behaviors in three different strains of drosophila pseudoobscura. hybridization studies were then carried out with flies from the diverged strains. the geotactic scores of the parents and f1 flies indicate that both negative and positive geotactic behaviors in these strains are strongly influenced by genes in the x chromosome. additional hybridization studies using flies from strains with similar phenotype ...1978565202
examination of allelic variation at the hexokinase loci of drosophila pseudoobscura and d. persimilis by different methods.recently a number of electrophoretic techniques have been applied to reveal the presence of additional genetic variation among the electrophoretic mobility classes of the highly polymorphic xanthine dehydrogenase (xdh ) and esterase-5 (est-5) loci. we examined the hexokinase loci of drosophila pseudoobscura and d. persimilis using a variety of techniques to determine whether further allelic variation could be revealed for these much less polymorphic loci and to analyze the nature of the known va ...197717248785
an experimental investigation of the unit charge model of protein polymorphism and its relation to the esterase-5 locus of drosophila pseudoobscura, drosophila persimilis, and drosophila miranda.the relationship between charge changes and electrophoretic mobility changes is investigated experimentally. the charge of several proteins is altered by reaction with small molecules of known structure and the change in electrophoretic mobility is measured. the method of ferguson plots is used to separate charge and shape components of mobility differences. the average effect of an amino acid charge change on the mobility of the esterase-5( 1.00) allele of drosophila pseudoobscura is estimated ...197717248784
a test for rare male mating advantage at an "enzyme locus" in drosophila.matings between drosophila pseudoobscura strains differing at the amylase (amy) locus were observed in elens-wattiaux chambers. males homozygous for either amy1.00 or amy0.84 alleles in the ch gene arrangement enjoyed a mating advantage when moderately rare, but none when quite rare. the minority male advantage for strains differing at the amy locus, and other loci linked to it, was comparable in size to that observed between strains carrying the st or ch gene arrangements, and either alike or d ...1977603476
drift or selection: a statistical test of gene frequency variation over generations.the method used by fisher and ford (1947) to study the spread of a gene in a natural population has been modified to analyze the variation in allele frequencies from generation to generation in a common experimental procedure. a further analysis has been developed that is more sensitive to directional trends in the allele frequency over generations, and its use in detecting the action of directional selection on gene frequency at a locus is discussed. the power of each of these statistical tests ...197717248769
gene frequency changes at the alpha-amylase locus in experimental populations of drosophila pseudoobscura.the frequencies of alleles at the alpha-amylase locus of d. pseudoobscura were followed in both large and small experimental populations. no evidence for balancing or directional selection was found, although our ability to detect weak selection is limited. the gene frequency changes in our experimental populations were consistent with the hypothesis of selective neutrality and genetic drift due to sampling error.197717248768
genic heterogeneity at two alcohol dehydrogenase loci in drosophila pseudoobscura and drosophila persimilis.a sequential electrophoretic survey of the second chromosome loci, alcohol dehydrogenase-6 (adh-6) and octanol dehydrogenase ( odh), was performed on 147 isochromosomal lines of drosophila pseudoobscura and 60 lines of its sibling species, d. persimilis. gels run with a variety of acrylamide concentrations and buffer ph's revealed the presence of 18 alleles of adh-6 in the two species, where only eight had been previously detected by conventional electrophoretic methods. only two alleles were ad ...197717248763
allelic variants at the xanthine dehydrogenase locus affecting enzyme activity in drosophila pseudoobscura.quantitative studies of enzyme activity on gels show about four-fold differences in enzyme activity of different xanthine dehydrogenase (xdh ) alleles. at least three different activity classes could be distinguished among the 23 strains isogenic for the xdh locus. no association of high activity with the high frequency electromorph was observed; instead, the low frequency electromorphs had 0.5 to 2 times the activity of the high frequency electromorph. the frequency of low activity, high activi ...197717248755
evaluation of the stepwise mutation model of electrophoretic mobility: comparison of the gel sieving behavior of alleles at the esterase-5 locus of drosophila pseudoobscura.seven alleles at the esterase-5 locus of drosophila pseudoobscura appear approximately uniformly spaced on 5% acrylamide gels. such stepwise "ladders" in mobility have been used to argue for the charge-state model of electrophoretic mobility. to evaluate this interpretation, flies of the seven strains were examined in replicate electrophoresis on polyacrylamide gels of differing pore size, permitting estimation of the relative contributions of charge and of size/conformation to electrophoretic m ...197717248754
a comparative study of the esterase-5 locus in drosophila pseudoobscura, d. persimilis and d. miranda.electrophoretic phenotypes of the esterase-5 locus were examined in the sibling species d. pseudoobscura, d. persimilis and d. miranda. d. persimilis alleles were found to have uniformly higher charge on monomers than corresponding alleles of either d. pseudoobscura or d. miranda. consequently, d. persimilis shares no alleles in common with either d. pseudoobscura or d. miranda, while the latter two species share a number of alleles. it was discovered that by increasing the concentration of acry ...1977863241
gene differences between the sex ratio and standard gene arrangements of the x chromosome in drosophila persimilis.the sibling species drosophila pseudoobscura and d. persimilis each carry two gene arrangements in the right arm of the x chromosome; standard (st) and sex ratio (sr). the sr sequence of d. persimilis and the st sequence of d. pseudoobscura have the same banding pattern. these cytologically identical arrangements carry different alleles at the esterase-5 (est-5) and phosphoglucomutase-1 ( pgm-1) loci. all the alleles on the sr arrangement of d. persimilis are also present on the st arrangement o ...197717248742
evolutionary divergence between two populations of drosophila pseudoobscura. 197728563476
genetic divergence in closely related sibling species drosophila pseudoobscura, drosophila persimilis and drosophila miranda. 197728567734
further studies on gene polymorphism in the mainbody and geographically isolated populations of drosophila pseudoobscura.we have examined polymorphism at 22 additional loci in the populations from the mainbody of drosophila pseudoobscura and an isolated population from bogotá, columbia, which also shows partial reproductive isolation from mainbody populations. these studies extend our previous observations of reduced gene polymorphism and apparent lack of unique allele in the bogotá population.1977863242
protein synthesis inhibition alters drosophila mating behavior.fruit fly drosophila pseudoobscura virgin ar females mate preferentially with ar males given a choice between ar and or males. however, ar females which mated with or males when young show a significant change in sexual selection in favor of or over ar males in subsequent simultaneous choice tests. ingestion of food moistened with 4 ml cycloheximide (400 microng/ml) produces 75% protein synthesis inhibition in the female flies. females exposed to cycloheximide (cxm) immediately after their initi ...1977857258
effects of age, rearing and mating experiences on frequency dependent sexual selection in drosophila pseudoobscura. 197628565052
the frequency and allelism of lethal chromosomes in isolated desert populations of drosophila pseudoobscura.second-chromosome lethals were extracted from four populations of drosophila pseudoobscura in southern california. two of the populations were from desert oases and two from the classic habitat on mt. san jacinto, previously studied by dobzhansky. allelism tests were made on the lethals within and between all locations. the frequency of lethal second-chromosomes in each location was 0.18, and this was not different from the results of other workers for samples throughout the species range. inter ...19761010313
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