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bichromosomal synthetic semilethals in drosophila pseudoobscura. 196514338225
genetic divergence in m. vetukhiv's experimental populations of drosophila pseudoobscura. 2. longevity. 196514297592
mating control by gene arrangements in drosophila pseudoobscura. 196617248341
purification of esterase-5 from drosophila pseudoobscura. 19665969303
comparison of selection responses on body weight under divergent larval density conditions in drosophila pseudoobscura. 19665968645
a molecular approach to the study of genic heterozygosity in natural populations. ii. amount of variation and degree of heterozygosity in natural populations of drosophila pseudoobscura. 19665968643
a molecular approach to the study of genic heterozygosity in natural populations. i. the number of alleles at different loci in drosophila pseudoobscura. 19665968642
sexual isolation caused by selection for positive and negative phototaxis and geotaxis in drosophila pseudoobscura. 19665229969
genetics of natural populations. xxxvii. the coadapted system of chromosomal variants in a population of drosophila pseudoobscura. 19665929240
equilibria for inversions induced by x-rays in isogenic strains of drosophila pseudoobscura. 19665929239
stability of chromosomal polymorphism in populations of drosophila pseudoobscura. 19665226966
mating speed and duration of copulation in drosophila pseudoobscura. 19665226959
the mutational load in two natural populations of drosophila pseudoobscura. 19665913286
selection for and against ethological isolation between drosophila pseudoobscura and drosophila persimilis. 196628562900
morphological variation in natural and experimental populations of drosophila pseudoobscura and drosophila persimilis. 196628564753
monthly frequency changes of drosophila pseudoobscura third chromosome gene arrangements in a california locality. 196628562913
comparative studies of arrangements within and between populations of drosophila pseudoobscura. 196628562896
genetics of natural populations. xxxviii. continuity and change in populations of drosophila pseudoobscura in western united states. 196628562981
experiments on random genetic drift and natural selection in drosophila pseudoobscura. 196628564754
genic heterogeneity within electrophoretic "alleles" and the pattern of variation among loci in drosophila pseudoobscura.an investigation, similar to our previously reported xanthine dehydrogenase study, was undertaken to examine the extent of hidden genic variation at nine loci (five larval proteins, three esterases and one aldehyde oxidase) by sequential application of various electrophoretic criteria employing ph, gel concentration and buffer variation. polymorphic loci appear to fall into two distinct groups: weakly polymorphic, including larval protein 6, 7, 8, 10 and 13 and esterase-1 and -6; and highly poly ...1966546677
selection and inversion polymorphism in experimental populations of drosophila pseudoobscura initiated with the chromosomal constitutions of natural populations. 196728563075
genetic divergence in m. vetukhiv's experimental populations of drosophila pseudoobscura. iv. relative viability. 19675587945
genetic loads affecting fertility in natural populations of drosophila pseudoobscura. 19675586879
genetic loads affecting longevity in natural populations of drosophila pseudoobscura. 19676057227
circadian systems. i. the driving oscillation and its assay in drosophila pseudoobscura. 19675237901
genetic loads affecting fecundity in natural populations of drosophila pseudoobscura. 19676040492
an experiment on migration and simultaneous selection for several traits in drosophila pseudoobscura. 19676036950
variability within and between strains for mating behavior parameters in drosophila pseudoobscura. 19676032107
further evidence for coadaptation in crosses between geographic populations of drosophila pseudoobscura. 19685713603
the genetics of drosophila mating behaviour. i. organization of mating speed in drosophila pseudoobscura. 19685709775
courtship and mating time in drosophila pseudoobscura. 19685709773
genetics of natural populations. xl. heterotic and deleterious effects of recessive lethals in populations of drosophila pseudoobscura. 19685705830
temperature compensation of the circadian oscillation in drosophila pseudoobscura and its entrainment by temperature cycles. 19685655535
selection for higher fitness in populations of drosophila pseudoobscura.four laboratory populations, each consisting of flies homozygous for a wild second chromosome, were maintained in population cages. three of them were initially characterized by low fecundity of the females; the fourth was a control. after 15 months, in all three populations with low fecundity this character was much improved; two of them, have reached the control level. the changes observed were presumably due to mutation and selection under highly competitive conditions.19685642574
frequency dependence of mating success in drosophila pseudoobscura. 19685647626
parental age effects in drosophila pseudoobscura. 19685697303
genetics of natural populations. xxxix. a test of the possible influence of two insecticides on the chromosomal polymorphism in drosophila pseudoobscura. 19685668291
selection for and against gregariousness in the choice of oviposition sites by drosophila pseudoobscura. 19685664388
uniform heterokaryotypic superiority for viability in a colorado population of drosophila pseudoobscura. 196828564814
the relationship between the intensity of light phases and the extent of phase shifts of the circadian rhythm in the eclosion rate of drosophila pseudoobscura. 19695372004
morphological differences between drosophila pseudoobscura populations selected for opposite geotaxes and phototaxes. 196917248462
the genetic basis of sound production in drosophila pseudoobscura and d. persimilis. 19695370966
factors determining rates of the evolution of fitness in laboratory populations of drosophila pseudoobscura. 196917248453
on the absence of circadian rhythmicity in drosophila pseudoobscura pupae. 19695798455
the genetics of drosophila mating behavior. ii. the genetic architecture of mating speed in drosophila pseudoobscura. 19695371028
chromosomal polymorphism and genetic load in drosophila pseudoobscura. 19695364967
a molecular approach to the study of genic heterozygosity in natural populations. iv. patterns of genic variation in central, marginal and isolated populations of drosophila pseudoobscura. 19695364966
action spectra for phase shifts of a circadian rhythm in drosophila.action spectra were determined for lightinduced phase shifts of the circadian rhythm of adult emergence in drosophila pseudoobscura. the action spectra for advance and delay phase shifts are similar; the most effective wavelengths are in the blue region, with a sharp cutoff above 500 nanometers. this similarity suggests that the same photoreceptive pigment mediates both advance and delay phase shifts.19695762935
artificial and natural selection for two behavioral traits in drosophila pseudoobscura.in an attempt to elucidate the genetic architecture of two behavioral traits, populations of drosophila pseudoobscura were selected for positive and for negative phototaxis and geotaxis. the selected populations diverged rapidly in their behavior (figs. 1 and 2). the selection was relaxed after 20 generations in the phototactic, and after 30 generations in the geotactic populations. the relaxation resulted in convergence almost as rapid as was the divergence under selection. the average phototac ...19695253666
a population cage test for heterosis in drosophila pseudoobscura. 19705512472
"sex ratio" in drosophila pseudoobscura: spermiogenic failure.contrary to earlier reports, testes of "sex ratio" drosophila pseudoobscura males have only half as many sperm per bundle as testes of normal males do. this fact, determined from electron micrographs, indicates that the functional pole hypothesis is not applicable to the action of "sex ratio."19705432586
concurrent inbreeding and selection in drosophila pseudoobscura. 19705479389
selection in experimental populations of drosophila pseudoobscura with different initial frequencies of chromosomal variants. 19705415223
adaptation by natural selection in populations of drosophila pseudoobscura. 19705413803
crystalline inclusions in the salivary gland cells of drosophila pseudoobscura. 19715092852
measurement of fitness at the esterase-5 locus in drosophila pseudoobscura. 19715097534
association of karyotype with body weight and resistance to desiccation in drosophila pseudoobscura. 19715563332
viabilities of third chromosomes of drosophila pseudoobscura differing in relative competitive fitness.arrowhead (ar) third chromosome arrangements of drosophila pseudoobscura, whose competitive fitnesses had been determined in population cages, were tested for their genetic loads in homozygous, heterozygous (homokaryotypic), and heterokaryotypic (ar/ch) combinations. the results showed that their competitive population cage performances were correlated to their viabilities as homozygotes but were not correlated to their viabilities as heterozygotes or as heterokaryotypes. however, the results do ...19724652876
studies on the sal locus in drosophila pseudoobscura. ii. modes of regulation of the sal banding pattern.from a consideration of genetic and chromosomal alterations which affect the banding pattern of a specific salivary chromosome region, it is concluded that (1) a regulator locus, sal, is closely linked with the region in question but separated from it spatially by a few bands; (2) either mutation of the sal locus or transfer of the region to a heterochromatic region affects the banding pattern similarly; and (3) the change probably consists of a compaction of dna and a concomitant inactivation o ...19724643822
studies on the sal locus in drosophila pseudoobscura. i. the banding pattern of the tip of salivary chromosome 3 in larvae homozygous and heterozygous for sal.in the mutant sal the banding pattern at the tip of chromosome 3 is changed. certain bands are compacted instead of being partially puffed. in sal(+)/sal heterozygotes, when the chromosome tips are paired they both show the sal(+) pattern or are intermediate; but when unpaired, each shows the pattern characteristic of its own genotype.19724647718
direct evidence of genic differentiation between sex ratio and standard gene arrangements of x chromosome in drosophila pseudoobscura.evidence of strong association of alleles at the esterase-5 and adult acid phosphatase-6 loci with the sex ratio and the standard x chromosome arrangements in d. pseudoobscura is presented. there is no differentiation at these two loci, either in the sex ratio or the standard arrangement from two widely separated geographic populations. at the esterase-5 locus, alleles characteristic of one arrangement are found in low frequencies in the other arrangement. it is concluded, from these and other o ...19725073855
developmental studies in drosophila. vi. ultrastructural analysis of the salivary glands of drosophila pseudoobscura during the late larval period. 19724340674
genetic analysis of geotactic and phototactic behavior in selected strains of drosophila pseudoobscura. 19724664205
developmental studies in drosophila. ii. ultrastructural analysis of the salivary glands of drosophila pseudoobscura during some stages of development. 19724335117
how genetic background masks single-gene heterosis in drosophila (polymorphism-selection-isoenzymes-inbreeding-fly).conditional heterosis associated with two isoallelic forms of octanol dehydrogenase in drosophila pseudoobscura has been detected in flies that have been (a) inbred for several generations to make the background genotype as homozygous as practicable, and (b) grown on a medium containing a small amount of octanol. the heterosis was first found in inbred males. the possibility that the effect in females was masked by x-linked polymorphic genes affecting the same fitness components as the locus for ...19724501117
chromosomal polymorphism in drosophila pseudoobscura used for diagnosis of geographic origin. 197228563351
maintenante of chromosomal polymorphism in a population of drosophila pseudoobscura: viability under crowded and uncrowded conditions. 197228563063
origin of reproductive isolation in the absence of apparent genic differentiation in a geographic isolate of drosophila pseudoobscura.f(1) males obtained from the cross of d. pseudoobscura females from bogotá (colombia) x males of this species from mainland, i.e. populations from various locations in the united states and from guatemala, are sterile. this sterility is due to genes located on the x chromosome and the autosomes; the y chromosome is not involved. the percentage of sterile males in backcrosses can be explained by assuming an interaction between two loci on the bogotá x chromosome and probably two loci, one each on ...19725073854
genetic divergence in body size among experimental populations of drosophila pseudoobscura kept at different temperatures. 197328564779
maintenance of chromosomal polymorphism in a population of drosophila pseudoobscura. ii. fecundity, longevity, viability and competitive fitness. 197328563660
studies on the sal locus in drosophila pseudoobscura. 3. the molecular pattern of dna in active and inactive chromosome regions. 19734762789
a differential effect of heavy water on temperature-dependent and temperature-compensated aspects of circadian system of drosophila pseudoobscura.d(2)o is the only "chemical" agent that consistently affects the frequency of circadian oscillations: its effect is now known to be so widespread and predictable that its action merits closer study as a potential clue to the currently obscure concrete nature of circadian oscillators. the great diversity of d(2)o effects on biological systems in general is briefly reviewed and the need for rejectable hypotheses concerning the action of d(2)o on circadian clocks is stressed because current specula ...19734516204
temporal frequency changes of enzyme and chromosomal polymorphisms in natural populations of drosophila.a comparative study of chromosomal and enzyme polymorphisms in drosophila pseudoobscura and in d. persimilis was conducted from april 1971 to october 1972 by taking samples at monthly intervals in two different localities. seasonal cyclic changes occur in the chromosomal polymorphisms. significant changes occur in the frequencies of the enzyme polymorphisms; preliminary evidence indicates that some of these changes may also be cyclic. natural selection is the main process responsible for the cha ...19734514981
chromosomal control of mating activity in drosophila pseudoobscura.lines containing two third-chromosome inversions (arrowhead and pikes peak) of drosophila pseudoobscura selected for fast and slow mating speed were crossed to a multichromosomal, dominant marker inversion stock, and strains with various combinations of chromosomal derivation were tested for their mating activity. when lines were selected isodirectionally with the known third-chromosome control, the third chromosome was found to possess major epistatic control over mating speed, followed by the ...19734510290
dosage compensation of genes on the left and right arms of the x chromosome of drosophila pseudoobscura and drosophila willistoni.we have investigated the occurrence of dosage compensation in d. willistoni and d. pseudoobscura, two species whose x chromosome is metacentric with one arm homologous to the x and the other homologous to the left arm of chromosome 3 of d. melanogaster. crude extracts were assayed for isocitrate dehydrogenase (xr), glucose-6-phosphate dehydrogenase (xl?), 6-phosphogluconate dehydrogenase (xl?), and alpha-glycerophosphate dehydrogenase (chromosome 2) in d. willistoni, and for esterase-5 (xr), glu ...19744455556
genetic background and the fitness of allozymes.experimental perturbations of gene frequency at the esterase-5 locus in drosophila pseudoobscura were carried out in a series of population cages started with differing numbers of founder chromosomes. cages founded with few chromosomes showed changes in gene frequency at the allozyme locus. such changes were less marked in cages founded with a larger sample of chromosomes. these experiments show the importance of linkage disequilibrium in affecting allozyme frequencies, and emphasize the necessi ...19744455555
esterases of drosophila. ii. biochemical studies of esterase-5 in d. pseudoobscura.in vitro enzyme hybridization was carried out with combinations of six allozymic variants of esterase-5 from drosophila pseudoobscura. studies on heat stability and specific activity changes accompanying hybridization were done to examine the possible expression of overdominance at the biochemical level. in 11 of 15 combinations no significant change in specific activity was found following hybridization. in two cases hybridization resulted in a decrease in activity in the mixture, while in two ...19744455554
rates of dispersal of drosophila pseudoobscura and its relatives. 19744154451
fitness of allozyme variants in drosophila pseudoobscura. ii. selection at the est-5, odh and mdh-2 loci. 19744452479
light dependence in matings of drosophila pseudoobscura. 19744414479
gene differences between the sex ratio and standard gene arrangements of the x chromosome and linkage disequilibrium between loci in the standard gene drosophila pseudoobscura.the standard and sex ratio gene arrangements of the x chromosome of d. pseudobscura differ from each other in allele frequencies at the four x chromosome loci, esterase-5, adult acid phosphatase-6, phosphoglucomutase-1 and octanol dehydrogenase-3. the standard arrangement which is the common arrangement in all populations is polymorphic at these loci in varying degrees, the geographically less widespread sex ratio arrangement has little polymorphism and is genically predominantly e-5(1.04) ap-6( ...19744417060
selection by fertility in drosophila pseudoobscura.fertility, the component of selection due to female fecundity and male mating success, differed significantly among the st/st, st/ar, and ar/ar karyotypes in experimental populations and varied with karyotypic frequency. in relation to st/ar, st/st females and males had higher fertilities at low frequency; ar/ar males and females were at a significant fertility disadvantage at intermediate frequency, while at low and at high frequencies their fertilities matched or exceeded that of the heterokar ...19744426507
age, experience, and rare-male mating advantages in drosophila pseudoobscura. 19744842092
cold temperature resistance, chromosomal polymorphism and interpopulation heterosis in drosophila pseudoobscura.descendants of two colorado, u.s.a., populations of d. pseudoobscura, boulder and la foret, were exposed to +2 degrees and -2 degrees . in third instar larvae from boulder ar and pp third chromosome gene arrangements survived better than tl and others, while the reverse situation occurred for la foret. deleterious dominant effects were observed for ar from la foret. in adults from boulder there was a trend towards greater survival for ar and pp than for other gene arrangements, while ar from la ...19744838761
on the very rapid enhancement by d2o of the temperature-tolerance of adult drosophila.deuterium oxide, d(2)o, increases the temperature-tolerance of drosophila pseudoobscura when it is administered to adult flies as a sucrose solution. the effect is very rapidly exerted; it is detected within 10 min after the flies have a brief (10 min) opportunity to drink. this increased resistance to heat-death surely implies an increased resistance of macromolecules to thermal denaturation. d(2)o is known to exert such an effect on in vitro protein solutions. the speed with which the increase ...19744521820
rigid and flexible chromosomal polymorphisms in neighboring populations of drosophila pseudoobscura. 197428563030
genetic analysis of hybrid sterility within the species drosophila pseudoobscura. 19744413557
population genetics of mexican drosophila. i. chromosomal variation in natural populations of drosophila pseudoobscura from central mexico.drosophila pseudoobscura populations of central mexico are chromosomally highly polymorphic. five gene arangements in the third chromosome are endemic, including the two newly described in the present article. the phylogenetic tree of the gene arrangements known in the species is shown in figure 1. the ones found in central mexico all belong to the santa cruz "phylad", while in the northern part of the species area both santa cruz and standard phylads are widespread. some inferences concerning t ...19751165399
selection for mating activity in two chromosomal arrangements of drosophila pseudoobscura. 197528563183
population density and mating rates in drosophila pseudoobscura. 197528555850
genetics of natural populations xlii. three decades of genetic change in drosophila pseudoobscura. 197528563287
chromosomal basis of dosage compensation in drosophila viii. faster replication and hyperactivity of both arms of the x-chromosome in males of drosophila pseudoobscura and their possible significance.3h-thymidine and 3h-uridine labeling patterns of the x-chromosome arms of drosophila pseudoobscura have been examined autoradiographically. results show that in all phases of replication, namely, initial, middle and terminal, both arms of the x-chromosome in the male are advanced by one or two steps of 3h-thymidine labeling in comparison with the autosomes, and both arms in the female show more or less similar labeling profile as the autosomes. both the arms in the male show pale stainability an ...19751201689
distribution among the chromosomes of drosophila pseudoobscura of the genes governing the response to light.most strains of drosophila pseudoobscura are neutral to light when tested in phototactic mazes. however, clear-cut photopositive and photogenative populations are obtained by selection over a series of generations. the genetic nature of the differences between the positive and negative populations has been studied in crosses in which the three large autosomes carried mutant markers. all chromosomes contain genes which influence the response to light. the third chromosome has the strongest effect ...19751205129
dna replication in polytene chromosomes of drosophila pseudoobscura: new facts & their implications. 19751218903
photobehavioral differentiation in natural populations of drosophila pseudoobscura and drosophila persimilis.the photoresponses of natural populations of d. pseudoobscura and d. persimilis, occurring sympatrically, are measured in two environmental conditions ("at rest" and "disturbed"). comparisons of the responses, intraspecifically and interspecifically, lead to the following conclusions. these must be considered within the confines of the operational nature of the measurement of laboratory photoresponses. (1) within each species population, significant nonenvironmental differentiation has been allo ...19751131147
a biometrical analysis of a mating characteristic in drosophilia.a model is described for the biometrical analysis of interaction behavioural characteristics. the model is illustrated by analysis of the mating speed of drosophila pseudoobscura derived from crosses of fast and of slow mating strains generated through artificial selection.19751054670
fitness of allozyme variants in drosophila pseudoobscura. i. selection at the pgm-1 and me-2 loci.we have studied in drosophila pseudoobscura the effect of allozyme variation on seven fitness components: female fecundity, egg hatchability, egg-to-adult survival under near-optimal and under competitive conditions, rate of development under near-optimal and under competitive conditions, and mating capacity of males. three genotypes at each of two loci, pgm-1 and me-2, have been studied in various combinations. these two loci are highly polymorphic in natural populations of d. pseudoobscura. st ...19751126623
further evidence for selective differences between isoalleles in drosophila.a number of separate strains of drosophila pseudoobscura were inbred for 38 generations of brother-sister mating with forced heterozygosity for two alleles of either the octanol dehydrogenase or esterase-5 locus. crosses were set up within each of these inbred lines such that simple mendelian ratios were expected, and eggs from these crosses were placed on media with additions simple chemicals likely to interact with alleles of the two loci--octanol and ethanol for the odh locus and tributyrin a ...19751126619
fitness of karyotypes in drosophila pseudoobscura.in the dynamics of the survival of chromosomal polymorphism selection may be operating at the genic level, at the chromosomal level or at the supergene level. tests designed to distinguish between these levels were run on drosophila pseudoobscura. there was no evidence for heterosis, a necessary requirement for gene-determined chromosomal polymorphism a strong chromosmal selection was observed. no evidence was found for the presence within one locality of more than a single superallele for each ...19751126618
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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