Publications

drosophila s virus, a hereditary reolike virus, probable agent of the morphological s character in drosophila simulans.	isometric reolike virions were found in all the examined drosophila simulans flies from two strains (simes-st and israel-st) presenting the s phenotype, a maternally inherited morphological trait (abnormalities of bristles). normal flies of both strains appeared virus-free. virions were found in the cytoplasm of male and female gonads and epidermal cells, including the bristle-forming cells, which appeared disorganized. steps of virogenesis were described. a positive correlation was demonstrated ...	1988	3346947
sexual isolation and courtship behavior in drosophila simulans, d. mauritiana, and their interspecific hybrids.		1988	3377736
mitochondrial dna variability in drosophila simulans: quasi absence of polymorphism within each of the three cytoplasmic races.	nucleotide variability of mtdna extracted from 144 isofemale lines collected in the whole range of d. simulans was analysed with 10-15 restriction enzymes and 73 lines were studied using one or a few enzymes. all clones were distributed into 3 mitochondrial genomes, sii, siii and siiii. these types are allopatric and can define geographic races. mixed populations occur only in madagascar and réunion, where siii and siiii are found together. among 40 sites detected with 10 enzymes, the variabilit ...	1988	2906636
natural populations of drosophila simulans show great uniformity of the mitochondrial dna restriction map.	the mitochondrial dna of 21 drosophila simulans isofemale lines of different geographic origins was digested with seven restriction endonucleases. all the lines, with one exception for one line and one enzyme, showed the same restriction patterns. the results confirm previous investigations showing great uniformity of the mtdna genome in d. simulans.	1988	3215515
organization and evolution of the alcohol dehydrogenase gene in drosophila.	the alcohol dehydrogenase (adh) gene was isolated from drosophila simulans and d. mauritiana, and the dna sequence of a 4.6-kb region, containing the structural gene and flanking sequence, was determined for each. these sequences were compared with the adh region of d. melanogaster to characterize changes that occur in the drosophila genome during evolution and to identify conserved sequences of functional importance. drosophila simulans and d. mauritiana adh are organized in a manner similar to ...	1988	3367783
linkage disequilibrium between enzymatic loci in natural populations of drosophila simulans.		1988	22879302
differing amounts of genetic polymorphism in testes and male accessory glands of drosophila melanogaster and drosophila simulans.	we surveyed genetic polymorphism by two-dimensional gel electrophoresis of male reproductive tract proteins in 20 isofemale lines each of drosophila melanogaster and drosophila simulans. after classifying 244 such proteins of drosophila melanogaster and 271 of drosophila simulans by their distribution between testes and accessory glands within the reproductive tract, significant correlations were found between genetic polymorphism and tissue distribution. in both species, gland-specific proteins ...	1988	3132149
maternally inherited transposon excision in drosophila simulans.	a mutation in the white gene of drosophila mauritiana resulting from insertion of the transposable element mariner exhibits genetic instability in germline and somatic cells. the instability is greatly enhanced in the presence of the trans-acting autosomal factor mos, giving eye-color mosaics with pigmented sectors of tissue on an otherwise peach-colored background. the mos factor, when introduced into the genome of the sibling species drosophila simulans, exhibited a dramatic maternal effect on ...	1988	2832948
genetics of sexual isolation between two sibling species, drosophila simulans and drosophila mauritiana.	drosophila simulans and drosophila mauritiana are sibling species that show substantial sexual isolation in one of their two reciprocal hybridizations. genetic analysis reveals that in females this isolation is caused by at least one recessive gene on each autosome, while the x chromosome has little or no effect. our results, combined with those of previous studies, show that in drosophila the genetics of sexual isolation differs from that of postzygotic reproductive isolation, which invariably ...	1989	2748596
nucleolar dominance and replicative dominance in drosophila interspecific hybrids.	the replication of the rdna complement of only one nucleolus organizer region during polytene chromosome formation (replicative dominance) was initially observed in drosophila melanogaster. here we demonstrate replicative dominance in drosophila simulans and d. melanogaster/d. simulans interspecific hybrids. a second nucleolar phenomenon, nucleolar dominance, is observed in the diploid tissue of interspecific hybrids. in this case only one of two nucleolus organizer regions forms a nucleolus. ho ...	1989	2511070
does postzygotic isolation result from improper dosage compensation?	the x chromosome invariably has the largest effect on postzygotic isolation between animal species. one explanation of this pattern is that inviability and sterility result from a breakdown in the dosage compensation of x-linked genes in hybrids. in drosophila, such breakdown could result from divergence of the genes used to assess the x/autosomal (x/a) ratio, and thus the sex, of an individual. i test this hypothesis by introducing mutant alleles of the sex-lethal locus into drosophila melanoga ...	1989	2503427
nucleotide variation and divergence in the histone multigene family in drosophila melanogaster.	nucleotide differences in the histone h3 gene family in drosophila melanogaster were studied on three levels: (1) within a chromosome, (2) within a population and (3) between species (d. melanogaster and drosophila simulans). the average difference within the h3 gene within a chromosome was 0.0040 per nucleotide site, about 52% of that within a population (0.0077). the proportion of divergent sites between the two species was 0.0575, which is about 8.5 times the difference within a species. the ...	1989	2499516
hybrid dysgenesis in drosophila simulans lines transformed with autonomous p elements.	the molecular and phenotypic analysis of several previously described p element-transformed lines of drosophila simulans was extended in order to determine whether they had the potential to produce a syndrome of p-m hybrid dysgenesis analogous to the one in drosophila melanogaster. the transformed line with the highest number of p elements at the beginning of the analysis, dsp pi-5c, developed strong p activity potential and p element regulation, properties characteristic of d. melanogaster p st ...	1989	2731724
drosophila s virus is a member of the reoviridae family.	the s character of drosophila simulans, the absence or malformation or both of bristles and other cuticular structures, was described by comendador (drosophila inf. serv. 55:26-28, 1980). its characteristics (maternal transmission, low pathogenicity, and sensitivity to temperature) suggested the existence of a virus as the causative agent. indeed, reoviruslike particles were found in subcuticular cells of s individuals, and its association with s phenotypic expression was shown. this virus was c ...	1989	2911113
genetic analysis of x-linked sterility in hybrids between three sibling species of drosophila.	three morphological markers (yellow, miniature, and forked) are used to map the location of x-chromosome segments causing male sterility in drosophila simulans/d. mauritiana and d. simulans/d. sechellia hybrids. in both hybridizations at least three sections of the chromosome contain genes with substantial effects on sterility. this represents the maximum genetic divergence detectable with the three markers, suggesting that the x chromosome contains many loci affecting postzygotic reproductive i ...	1989	2732092
the generation of transplasmic drosophila simulans by cytoplasmic injection: effects of segregation and selection on the perpetuation of mitochondrial dna heteroplasmy.	experimental transplasmic drosophila simulans were obtained through cytoplasm microinjection between eggs carrying different mitochondrial genomes. these genomes (siii and siiii) show a 1.5% difference in their sequences. they produced a large number of heteroplasmic flies in their f1 progeny and several flies were still heteroplasmic at the eighth generation. the distribution of frequencies of mitochondrial genotypes in the offspring of heteroplasmic females suggests that the stochastic process ...	1989	2608025
drosophila simulans cu-zn superoxide dismutase gene sequence.		1989	2780301
seasonal change in metabolic rate of drosophila simulans.	1. second-generation descendents of wild-caught female drosophila simulans sturtevant collected at different seasons from gainesville, florida, usa, were reared under a constant temperature and food level but with seasonally variable photoperiods. 2. body weight and metabolic rate, after adjustment to a common body weight, were higher in descendents of flies collected in fall and winter. 3. temperature sensitivity (q10) of metabolic rate was also related to season: higher q10 values were associa ...	1990	1981031
active mariner transposable elements are widespread in natural populations of drosophila simulans.	the occurrence of active, or autonomous, mariner elements was investigated by crossing white-peach mutant drosophila simulans females with wild-type males from various geographic origins. from a total of 194 experimental crosses only 17 failed to produce progeny with eye mosaicism (mos, i.e. pigmented spots in otherwise white-peach eyes). therefore, active mariner elements inducing somatic excision of the copy inserted at the white locus are abundant in all populations sampled. in the experiment ...	1990	1980741
dynamics of p-m hybrid dysgenesis in p-transformed lines of drosophila simulans.	an autonomous p element from drosophila melanogaster was introduced by microinjection into the germ line of its sibling species, drosophila simulans. the invasion kinetics of p elements was studied in seven independent lines over 60 generations, using gel blotting, in situ hybridization, and dysgenic crosses. some of the main phenotypic and molecular characteristics of p-m hybrid dysgenesis were observed, i.e., gonadal dysgenesis (gd sterility), chromosome rearrangements, and the occurrence of d ...	1990	28568199
mitochondrial dna polymorphism and cytoplasmic incompatibility in natural populations of drosophila simulans.		1990	28563884
rapid evolution in a fraction of the drosophila nuclear genome.	previous observations have indicated that drosophila dna contains a component that evolves so rapidly that it fails to hybridize between the dnas of sibling species. to establish the reality of this component and study its properties, the fraction (about 20%) of drosophila simulans (dsim) dna that fails to hybridize to drosophila melanogaster (dmel) dna has been isolated. the majority of the hybridizable part of this isolated fraction (based on control tests on dsim dna) fails to hybridize with ...	1990	2109090
genetic basis of the difference in alcohol dehydrogenase expression between drosophila melanogaster and drosophila simulans.	drosophila melanogaster and its sibling species, drosophila simulans, differ in expression of the enzyme alcohol dehydrogenase (adh). adult melanogaster flies that are homozygous for the slow allozyme have approximately twice the level of adh activity and crossreacting material as simulans adults. there is no corresponding difference in adh mrna, however, so this difference in adh protein level is evidently due to a difference in the rate of translation of the two rnas and/or to a difference in ...	1990	2124699
an unusual y chromosome of drosophila simulans carrying amplified rdna spacer without rrna genes.	the x and y chromosomes of drosophila melanogaster each contain a cluster of several hundred ribosomal rna genes (rdna). a nontranscribed spacer region separates adjacent rrna genes and contains tandem copies of 240 bp repeats that include the initiation site for rna polymerase i transcription. we show here that drosophila simulans, a sibling species of d. melanogaster, contains few, if any, rrna genes on its y chromosome but carries instead a large block (3,000 kb or 12,500 copies) of 240 bp no ...	1990	2379820
molecular evolution of drosophila metallothionein genes.	the metallothionein genes of drosophila melanogaster, mtn and mto, may play an important role in heavy metal detoxification. several different tandem duplications of mtn have been shown to increase cadmium and copper tolerance, as well as mtn expression. in order to investigate the possibility of increased selection for duplications of these genes in natural populations exposed to high levels of heavy metals, we compared the frequencies of such duplications among flies collected from metal-conta ...	1990	1981765
evolution of drosophila mitochondrial dna and the history of the melanogaster subgroup.	the nucleotide sequences of a common region of 15 mitochondrial dnas (mtdnas) sampled from the drosophila melanogaster subgroup were determined. the region is 2527 base pairs long, including most of the nadh dehydrogenase subunit 2 and cytochrome oxidase subunit 1 genes punctuated by three trna genes. the comparative study revealed (i) the extremely low saturation level of transitional differences, (ii) recombination or variable substitution rates even within species, (iii) long persistence time ...	1990	2124697
is there selection on rflp differences in mitochondrial dna?	experimental populations of drosophila simulans were established for the purpose of detecting the presence or absence of selection on a restriction fragment length polymorphism in mitochondrial dna (mtdna). it was then discovered that the founding strains differed with respect to the rickettsia-mediated incompatibility system in this species, which is maternally transmitted together with the mtdna differences. a population model was constructed using the known fitness effects of the incompatibil ...	1990	1974225
factors affecting the distribution of cytoplasmic incompatibility in drosophila simulans.	in drosophila simulans a wolbachia-like microorganism is responsible for reduced egg-hatch when infected males mate with uninfected females. both incompatibility types have previously been found in north america, europe and africa. some california populations have remained polymorphic for over two years, and the infection is apparently spreading in central california. egg hatch proportions for wild-caught females from polymorphic populations show that the incompatibility system acts in nature, b ...	1990	2076821
bidirectional incompatibility between conspecific populations of drosophila simulans.	cytoplasmic incompatibility (ci) describes the phenomenon whereby eggs fertilized by sperm from insects infected with a rickettsial endosymbiont fail to hatch. unidirectional ci between conspecific populations of insects is a well documented phenomenon. bidirectional ci has, however, only been described in mosquito populations, and recently between closely related species of parasitic wasps, where it is of interest as both an unusual form of reproductive isolation and as a potential means of ins ...	1990	2234083
the effect of heteroplasmy on cytoplasmic incompatibility in transplasmic lines of drosophila simulans showing a complete replacement of the mitochondrial dna.	unidirectional cytoplasmic incompatibility has been observed in crosses between different strains of drosophila simulans when the males, but not the females, involved in the crosses are infected with intracellular rickettsia-like microorganisms. in contrast to what is known about this system an unexpected partial incompatibility has been observed between two infected strains. transplasmic lines have been constructed in the laboratory to investigate this phenomenon. the injection of a foreign inf ...	1991	2010316
host-plant specialization in the drosophila melanogaster species complex: a physiological, behavioral, and genetical analysis.	drosophila sechellia, endemic to the seychelles, breeds in a single resource, morinda citrifolia, whereas its close sympatric relative, drosophila simulans, is a cosmopolitan generalist breeding in a great variety of resources. the effects of morinda on various fitness traits of these two species, their f1 hybrids, and reciprocal backcrosses were analyzed. morinda fruit is highly toxic to drosophila species, except d. sechellia. the toxicity is expressed in adults, embryos, and larvae. in embryo ...	1991	1900368
geographic distribution and inheritance of three cytoplasmic incompatibility types in drosophila simulans.	wolbachia-like microorganisms have been implicated in unidirectional cytoplasmic incompatibility between strains of drosophila simulans. reduced egg eclosion occurs when females from uninfected strains (type w) are crossed with males from infected strains (type r). here we characterize a third incompatibility type (type s) which is also correlated with the presence of wolbachia-like microorganisms. despite the fact that the symbionts cannot be morphologically distinguished, we observed complete ...	1991	1743484
introduction of the transposable element mariner into the germline of drosophila melanogaster.	a chimeric white gene (wpch) and other constructs containing the transposable element mariner from drosophila mauritiana were introduced into the germline of drosophila melanogaster using transformation mediated by the p element. in the absence of other mariner elements, the wpch allele is genetically stable in both germ cells and somatic cells, indicating that the peach element (i.e., the particular copy of mariner inserted in the wpch allele) is inactive. however, in the presence of the active ...	1991	1649067
identification of nucleotide substitutions necessary for trans-activation of mariner transposable elements in drosophila: analysis of naturally occurring elements.	six copies of the mariner element from the genomes of drosophila mauritiana and drosophila simulans were chosen at random for dna sequencing and functional analysis and compared with the highly active element mos1 and the inactive element peach. all elements were 1286 base pairs in length, but among them there were 18 nucleotide differences. as assayed in drosophila melanogaster, three of the elements were apparently nonfunctional, two were marginally functional, and one had moderate activity th ...	1991	1655567
molecular transfer of a species-specific behavior from drosophila simulans to drosophila melanogaster.	drosophila males modulate the interpulse intervals produced during their courtship songs. these song cycles, which are altered by mutations in the clock gene period, exhibit a species-specific variation that facilitates mating. we have used chimeric period gene constructs from drosophila melanogaster and drosophila simulans in germline transformation experiments to map the genetic control of their song rhythm difference to a small segment of the amino acid encoding information within this gene.	1991	1900131
developmental stability in hybrids between the sibling species pair, drosophila melanogaster and drosophila simulans.	drosophila melanogaster and its sibling species d.simulans were hybridized in the laboratory to test the hypothesis that developmental homeostasis in hybrids between two species having no prior gene flow would be significantly reduced. developmental stability was assessed by measuring fluctuating asymmetry for three bilateral traits: sternopleural chaetae, wing length, and fronto-orbital plus frontal chaetae. male f1 hybrids showed no decrease in developmental stability compared to males of pare ...	1991	1756963
lack of polymorphism on the drosophila fourth chromosome resulting from selection.	evolutionary processes can be inferred from comparisons of intraspecific polymorphism and interspecific divergence. we sequenced a 1.1-kb fragment of the cubitus interruptus dominant (cid) locus located on the nonrecombining fourth chromosome for ten natural lines of drosophila melanogaster and nine of drosophila simulans. we found no polymorphism within d. melanogaster and a single polymorphism within d. simulans; divergence between the species was about 5%. comparison with the alcohol dehydrog ...	1991	1686006
molecular population genetics of the distal portion of the x chromosome in drosophila: evidence for genetic hitchhiking of the yellow-achaete region.	we have estimated dna sequence variation and differentiation within and between drosophila melanogaster and its sibling species, drosophila simulans, using six-cutter restriction site variation at yellow-achaete (y-ac), phosphogluconate dehydrogenase (pgd), and period (per). these three gene regions are of varying distance from the telomere of the x chromosome and range from very low to moderate rates of recombination in d. melanogaster. according to tajima's test of neutrality, the pgd region h ...	1991	1664405
alfred henry sturtevant and crosses between drosophila melanogaster and drosophila simulans.		1991	1936952
insertion sites of the transposable element mariner are fixed in the genome of drosophila sechellia.	the abundance of the transposable element mariner differs dramatically in the genomes of the closely related species drosophila simulans, d. mauritiana, d. sechellia, and d. melanogaster. natural populations of d. simulans and d. mauritiana have 1-10 and 20-30 copies per diploid genome, respectively, and the insertion sites are polymorphic. the element has not been found in d. melanogaster. in this paper we show that d. sechellia, a species endemic to the seychelles islands, contains only two ma ...	1991	1660073
extinction due to evolution of a competitor.	when drosophila simulans and drosophila funebris were cultured together in population cages over many generations, there was a prolonged period of apparently stable coexistence followed by a rapid exclusion of d. funebris. as both species maintained large population sizes in monocultures it follows that the extinctions of d. funebris in the mixed-species cultures must have been caused by d. simulans. the time to extinction of d. funebris ranged from 26 weeks in one cage, to between 40 and 48 wee ...	1991	28567883
cytoplasmic incompatibility in drosophila populations: influence of assortative mating on symbiont distribution.	cytoplasmic incompatibility is known to occur between strains of both drosophila simulans and d. melanogaster. incompatibility is associated with the infection of drosophila with microorganismal endosymbionts. this paper reports survey work conducted on strains of d. simulans and d. melanogaster from diverse geographical locations finding that infected populations are relatively rare and scattered in their distribution. the distribution of infected populations of d. simulans appears to be at odd ...	1991	1787328
rapid spread of an inherited incompatibility factor in california drosophila.	in drosophila simulans in california, an inherited cytoplasmic incompatibility factor reduces egg hatch when infected males mate with uninfected females. the infection is spreading at a rate of more than 100 km per year; populations in which the infection was rare have become almost completely infected within three years. analyses of the spread using estimates of selection in the field suggest dispersal distances far higher than those found by direct observation of flies. hence, occasional long- ...	1991	1896086
[benzo(a)pyrene pretreatment of drosophila simulans mutant strain results in the induction of aberrant isoform of cytochrome p-450 with increased capacity to metabolize benzo(a)pyrene].	the basal level of benzo(a)pyrene monooxygenase, epoxide hydrolase and glutathione s-transferase activity as well as the content of cytochrome p-450 were found the same in both compared benzo(a)pyrene (bp) sensitive d. simulans strain 364yv and bp-resistant wild one (turku). phenobarbital pretreatment resulted in the same increase level of these enzyme activities in both strains. bp-pretreatment of 364yv flies decreased the amount of the cytochrome p-450 but raised up the turnover of bp per mole ...	1991	1786390
genetic control of pheromones in drosophila simulans. i. ngbo, a locus on the second chromosome.	7-tricosene and 7-pentacosene are predominant hydrocarbons on the cuticle of both sexes in drosophila simulans. the pheromonal role of 7-tricosene has been clearly established for conspecific males, while a synergistic effect for 7-pentacosene has been postulated. interstrain variation for the production of both compounds is very marked, but similar for both sexes. the genetic basis of this polymorphism was investigated. a major role was found for the second chromosome, which controls the 7-tric ...	1991	2071017
mitochondrial dna heteroplasmy maintained in natural populations of drosophila simulans in réunion.	mitochondrial dna (mtdna) variation in drosophila simulans was studied to determine whether the cytoplasmic state of mtdna heteroplasmy persists in natural populations in réunion. for this purpose, 172 isofemale lines, newly collected from two local populations, were examined, among which three types of mtdna (siii, siiii and siiii') were found, based on the hpa ii restriction pattern. ten of the lines were heteroplasmic for a combination of siii and siiii, as determined by autoradiography. the ...	1991	2055455
[a mutant strain of drosophila simulans sensitive to the toxic and mutagenic action of benz(a)pyrene].	a 364 yv strain sensitive to the toxic effect of benzo(a)pyrene (bp) was identified among 49 mutant strains of drosophila simulans. heterozygotes female 364 x male turku obtained by crossing 364 yv species with those of wild bp-resistant turku strain were more sensitive than female turku x male 364 heterozygotes to both toxic and mutagenic effects of the carcinogen in the test of induction of somatic mosaicism with the yellow marker. non-carcinogenic pyrene appeared weekly toxic and non-mutageni ...	1991	1842655
population genetics of polymorphism and divergence.	frequencies of mutant sites are modeled as a poisson random field in two species that share a sufficiently recent common ancestor. the selective effect of the new alleles can be favorable, neutral, or detrimental. the model is applied to the sample configurations of nucleotides in the alcohol dehydrogenase gene (adh) in drosophila simulans and drosophila yakuba. assuming a synonymous mutation rate of 1.5 x 10(-8) per site per year and 10 generations per year, we obtain estimates for the effectiv ...	1992	1459433
dynamics of cytoplasmic incompatibility and mtdna variation in natural drosophila simulans populations.	in drosophila simulans a cytoplasmically transmitted microorganism causes reduced egg hatch when infected males mate with uninfected females. the infection is rapidly spreading northward in california. data on a specific mtdna restriction site length polymorphism show that changes in the frequency of mtdna variants are associated with this spread. all infected flies possess the same mtdna allele, whereas the uninfected flies are polymorphic. given that both paternal inheritance of the infection ...	1992	1468627
xenobiotic-metabolizing enzymes and benzo[a]pyrene metabolism in the benzo[a]pyrene-sensitive mutant strain of drosophila simulans.	basal levels of aryl hydrocarbon hydroxylase, epoxide hydrolase and glutathione s-transferase enzyme activities, cytochrome p-450 content and inducibility of enzymes with phenobarbital were found to be similar in the microsomes of d. simulans mutant strain 364yv, which is sensitive to the toxic and mutagenic effects of benzo[a]pyrene (bp), and of the wild resistant turku strain. in contrast, increases in the rate of bp turnover per molecule of cytochrome p-450, intensity of the hemoprotein band ...	1992	1383701
genetics of sexual isolation in females of the drosophila simulans species complex.	genetic analysis of hybrids between drosophila simulans and d. sechellia shows that sexual isolation in females is caused by at least two genes, one on each major autosome, while the x chromosome has no effect. these results are similar to those of a previous study of hybrids between d. simulans and another sibling species, d. mauritiana. in this latter hybridization, each arm of the second chromosome carries genes causing sexual isolation in females, implying a total divergence of at least thre ...	1992	1452013
location of x-linked polygenic effects causing sterility in male hybrids of drosophila simulans and d. mauritiana.	there is general agreement that hybrid male sterility in drosophila is caused by changes at several (perhaps many) factors, most of them located on the x chromosome. these factors have been generally considered as major genes, each one of them able to bring about sterility by itself. however, the evidence on this last point is not conclusive. in principle, the possibility that they correspond to located polygenic effects instead of genes with a large effect cannot be excluded. this paper shows t ...	1992	1559838
the genetic basis of sexual isolation between drosophila melanogaster and d. simulans.	the genetic analysis of sexual isolation between the closely-related species drosophila melanogaster and drosophila simulans involved two experiments with no-choice tests. the efficiency of sexual isolation was measured by the frequency of courtship initiation and interspecific mating. we first surveyed the variation in sexual isolation between d. melanogaster strains and d. simulans strains of different geographic origin. then, to investigate variation in sexual isolation within strains, we mad ...	1992	28568993
an empirical test of the meiotic drive models of hybrid sterility: sex-ratio data from hybrids between drosophila simulans and drosophila sechellia.	recently, there has been much discussion regarding the hypothesis that divergence of meiotic drive systems in isolated populations can generate the patterns of reproductive isolation observed in animal hybridizations. one prediction from this hypothesis is that the sex ratio of hybrids with heterospecific sex chromosomes should greatly deviate from the mendelian expectation of 50% female. from sex-ratio data in our drosophila hybridization studies, we find no such deviation: the sex ratio of off ...	1992	1551573
a comprehensive study of genic variation in natural populations of drosophila melanogaster. vi. patterns and processes of genic divergence between d. melanogaster and its sibling species, drosophila simulans.	we present here an extensive set of data on allelic differences between homologous proteins of drosophila melanogaster and its sibling species, drosophila simulans, obtained by nondenaturing one-dimensional, and denaturing two-dimensional gel electrophoresis. the data suggest that, for these two species, (1) approximately 10% of protein-coding loci have no alleles in common in our sample, (2) the extent of genic variation at a locus (mean heterozygosity) within a species is not correlated with t ...	1992	1582561
sequence analysis of the indirect flight muscle actin-encoding gene of drosophila simulans.	a genomic clone of the drosophila simulans indirect flight muscle actin-encoding gene (act88f) has been isolated, and the sequence of a 3358-nucleotide segment corresponding to the drosophila melanogaster act88f transcription unit is presented. the act88f homologs in these two sibling species encode identical proteins and the general genomic organization of the act88f locus is highly conserved, including the location of the transcription start point, and the size and position of intron/exon junc ...	1992	1511890
interspecific comparison of the transformer gene of drosophila reveals an unusually high degree of evolutionary divergence.	the transformer (tra) gene of drosophila melanogaster occupies an intermediate position in the regulatory pathway controlling all aspects of somatic sexual differentiation. the female-specific expression of this gene's function is regulated by the sex lethal (sxl) gene, through a mechanism involving sex-specific alternative splicing of tra pre-mrna. the tra gene encodes a protein that is thought to act in conjunction with the transformer-2 (tra-2) gene product to control the sex-specific process ...	1992	1592233
intraspecific and interspecific variation at the y-ac-sc region of drosophila simulans and drosophila melanogaster.	a 2.2-kb region including the ac gene of drosophila simulans has been sequenced. interspecific divergence between drosophila melanogaster and d. simulans was estimated as 0.0695 and 0.0558 for silent and for all sites, respectively. estimated silent site divergence for the ac region is comparable to that estimated for other regions of the genome between these species, indicating that silent sites of the ac region are not under significantly stronger functional constraint. intraspecific variation ...	1992	1582559
[comparative analysis of the localization and mobility of retrotransposons in sibling species drosophila simulans and drosophila melanogaster].	the distribution of four retrotransposon families (mdg1, mdg3, mdg4 and copia) on polytene chromosomes of different (from 9 to 15) drosophila simulans strains is studied. the mean number of mdg1 and copia euchromatic hybridization sites (3 sites for each element) is drastically decreased in d. simulans in comparison with d. melanogaster (24 and 18 sites respectively). the mean number of mdg3 sites of hybridization is 5 in d. simulans against 12 in d. melanogaster. as for mdg4 both species have o ...	1992	1322343
efficient amplification of drosophila simulans copia directed by high-level reverse transcriptase activity associated with copia virus-like particles.	the number of retrotransposon copia per genome in drosophila melanogaster cultured cells is two to three times higher than that in d. melanogaster embryo cells. here, we have found that the genome of the related species, drosophila simulans, contains in cultured cells more efficiently amplified copia dna (approximately ten fold). furthermore, we analyzed copia virus-like particles (vlps) prepared from d. melanogaster and d. simulans cultured cells, which contain copia rna and reverse transcripta ...	1992	1383092
sequence analysis of active mariner elements in natural populations of drosophila simulans.	active and inactive mariner elements from natural and laboratory populations of drosophila simulans were isolated and sequenced in order to assess their nucleotide variability and to compare them with previously isolated mariner elements from the sibling species drosophila mauritiana and drosophila sechellia. the active elements of d. simulans are very similar among themselves (average 99.7% nucleotide identity), suggesting that the level of mariner expression in different natural populations is ...	1992	1312979
polymorphism and divergence in the mst26a male accessory gland gene region in drosophila.	drosophila males, like males of most other insects, transfer a group of specific proteins to the females during mating. these proteins are produced primarily in the accessory gland and are likely to influence the female's reproduction. the results of studies of dna sequence polymorphism and divergence in two genes coding for male accessory gland proteins of drosophila are reported here. the mst26aa and mst26ab transcription units are tandemly arranged in a approximately 1.6-kb segment in drosoph ...	1992	1361475
further observation of paternal transmission of drosophila mitochondrial dna by pcr selective amplification method.	by designing 3' ends of primers in pcr (polymerase chain reaction), a specific dna fragment was selectively amplified in the presence of a 10(3)-fold excess of highly homologous (sequence difference ca. 2%) opponent dna. this technique was applied in detecting paternal leakage of mitochondrial dna (mtdna) in intraspecific crosses of drosophila simulans and interspecific crosses of drosophila simulans and drosophila mauritiana. the mtdna types of their progeny were analysed by selective amplifica ...	1992	1628820
a drosophila simulans mutant strain sensitive to benzo[a]pyrene and 2-acetylaminofluorene.	we have identified a drosophila simulans mutant, 364 yu, that is sensitive to the toxic effects of the procarcinogens b(a)p and 2-aaf. heterozygotes obtained by crossing it to the wild resistant turku strain (female 364 yu x male turku) were more sensitive than heterozygotes obtained from the reciprocal cross (female turku x male 364 yu) to both the toxic and the mutagenic effects of b(a)p in drosophila tests that measured lethality and the induction of somatic mosaicism, respectively. the non-c ...	1992	1378181
molecular identification of wolbachia, the agent of cytoplasmic incompatibility in drosophila simulans, and variability in relation with host mitochondrial types.	sequences of a segment of the 16s ribosomal dna of wolbachia, a rickettsia-like microorganism responsible for cytoplasmic incompatibility in drosophila simulans, have been obtained after polymerase chain reaction (pcr) amplification. their comparison with other eubacterial sequences allows us to assign these endosymbionts to the alpha subdivision of purple bacteria. four related sequences have been obtained for microorganisms carried by eight isofemale lines representative of the three mitochond ...	1992	1350096
transmission of the hereditary s character in drosophila simulans: effects of aging and temperature treatments.	the expression of the s character of drosophila simulans associated to hereditary reovirus dsv is affected by the rearing temperature. the transmission of the s character and the consequences of the length of high temperature (28 degrees c) treatments on that transmission were investigated. larvae treated at 28 degrees c from eclosion to imaginal emergence produce few s individuals in the offspring. the offspring of larvae treated between the 144th hr of development (middle of the pupal stage) a ...	1992	1607670
localization of ribosomal dna insertion elements in polytene chromosomes of drosophila simulans, drosophila mauritiana and their interspecific hybrids.	the locations of the ribosomal dna (rdna) insertion elements type i and type ii along the polytene chromosomes of three drosophila species of the melanogaster subgroup--d. simulans, d. mauritiana and d. melanogaster--have been compared. in situ hybridization has shown that the intragenomic distribution of type i as well as of type ii insertions is different for these related species. in particular, we have revealed rdna-free autosomal sites, containing type ii element sequences within the d. sim ...	1992	1325940
cloning and characterization of an ftsz homologue from a bacterial symbiont of drosophila melanogaster.	a 1194 bp open reading frame that codes for a 398 amino acid peptide was cloned from a lambda gt11 library of drosophila melanogaster genomic dna. the predicted peptide sequence is very similar to three previously characterized protein sequences that are encoded by the ftsz genes in escherichia coli, bacillus subtilis and rhizobium meliloti. the ftsz protein has a major role in the initiation of cell division in prokaryotic cells. using a tetracycline treatment that eradicates bacterial parasite ...	1993	7689140
the reproductive incompatibility system in drosophila simulans: dapi-staining analysis of the wolbachia symbionts in sperm cysts.	any hitherto available technique used to detect the presence of wolbachia, a rickettsia-like endosymbiont of drosophila simulans, i.e., crossing with tester strains, electron microscope observations, dapi-staining of embryo, or amplification of specific sequences by pcr are notably time-consuming techniques. staining sperm cysts with the fluorochrome dapi is here shown to be a fast and reliable technique to detect the symbiont and evaluate the level of infection of individual males. wolbachia ce ...	1993	7689622
evidence for a wolbachia symbiont in drosophila melanogaster.	the bacterial cell division gene, ftsz, was used as a specific probe to show the presence of a symbiotic bacterium in two wild type strains of drosophila melanogaster. under stringent hybridization conditions we have shown that the bacterium is transferred to the progeny of these strains from infected mothers and can be eradicated by treatment with the antibiotic tetracycline. we have characterized this bacterium, by amplifying and sequencing its 16s rrna gene, as being a member of the genus wol ...	1993	7691685
interspecific and intraspecific horizontal transfer of wolbachia in drosophila.	cytoplasmic incompatibility (ci) in drosophila simulans is related to infection of the germ line by a rickettsial endosymbiont (genus wolbachia). wolbachia were transferred by microinjection of egg cytoplasm into uninfected eggs of both d. simulans and d. melanogaster to generate infected populations. transinfected strains of d. melanogaster with lower densities of wolbachia than the naturally infected d. simulans strain did not express high levels of ci. however, transinfected d. melanogaster e ...	1993	8511587
a combined classical genetic and high resolution two-dimensional electrophoretic approach to the assessment of the number of genes affecting hybrid male sterility in drosophila simulans and drosophila sechellia.	we have attempted to estimate the number of genes involved in postzygotic reproductive isolation between two closely related species, drosophila simulans and drosophila sechellia, by a novel approach that involves the use of high resolution two-dimensional gel electrophoresis (2de) to examine testis proteins in parents, hybrids and fertile and sterile backcross progenies. the important results that have emerged from this study are as follows: (1) about 8% of about 1000 proteins examined showed d ...	1993	8224814
dna sequence variation at the period locus within and among species of the drosophila melanogaster complex.	a 1.9-kilobase region of the period locus was sequenced in six individuals of drosophila melanogaster and from six individuals of each of three sibling species: drosophila simulans, drosophila sechellia and drosophila mauritiana. extensive genealogical analysis of 174 polymorphic sites reveals a complex history. it appears that d. simulans, as a large population still segregating very old lineages, gave rise to the island species d. mauritiana and d. sechellia. rather than considering these spec ...	1993	8436278
hybrid lethal systems in the drosophila melanogaster species complex. ii. the zygotic hybrid rescue (zhr) gene of d. melanogaster.	hybrid females from drosophila simulans females x drosophila melanogaster males die as embryos while hybrid males from the reciprocal cross die as larvae. we have recovered a mutation in melanogaster that rescues the former hybrid females. it was located on the x chromosome at a position close to the centromere, and it was a zygotically acting gene, in contrast with mhr (maternal hybrid rescue) in simulans that rescues the same hybrids maternally. we named it zhr (zygotic hybrid rescue). the gen ...	1993	8436277
evolution of postmating reproductive isolation: measuring the fitness effects of chromosomal regions containing hybrid male sterility factors.	at least six regions of the x chromosome can cause male sterility when introgressed from drosophila mauritiana into drosophila simulans. in this article, we present the results of the other fitness effects caused by two x-linked regions that contain hybrid male sterility factors. in both regions, females that are heterozygous for an introgression with such a sterility factor produce substantially-fewer offspring than females heterozygous for an introgression that lacks the sterility factor. thus ...	1993	19425976
regulatory aspects of esterase 6 activity variation in sibling drosophila species.	esterase 6 in drosophila melanogaster, drosophila simulans and drosophila mauritiana is produced in several life stages and diverse tissues, but the major pulse of expression is in the sperm ejaculatory duct of adult males. comparison of est6 activity levels among several lines of d. melanogaster, d. simulans and d. mauritiana reveals two major quantitative differences among the species. first, newly eclosed females of both d. simulans and d. mauritiana show significantly higher est6 activity th ...	1993	8360077
genetics of reproductive isolation in the drosophila simulans clade: dna marker-assisted mapping and characterization of a hybrid-male sterility gene, odysseus (ods).	in this study, we address the question of whether there exist major genes that cause complete male sterility in the interspecific hybrids of drosophila and, if they do, how these genes may be characterized at the molecular level. our approach is to introgress small segments of the x chromosome from drosophila mauritiana (or drosophila sechellia) into drosophila simulans by repeated backcrosses for more than 20 generations. the introgressions are monitored by both visible mutations and a series o ...	1993	8514135
the genetic basis of haldane's rule and the nature of asymmetric hybrid male sterility among drosophila simulans, drosophila mauritiana and drosophila sechellia.	haldane's rule (i.e., the preferential hybrid sterility and inviability of heterogametic sex) has been known for 70 years, but its genetic basis, which is crucial to the understanding of the process of species formation, remains unclear. in the present study, we have investigated the genetic basis of hybrid male sterility using drosophila simulans, drosophila mauritiana and drosophila sechellia. an introgression of d. sechellia y chromosome into a fairly homogenous background of d. simulans did ...	1993	8514134
hybrid lethal systems in the drosophila melanogaster species complex. i. the maternal hybrid rescue (mhr) gene of drosophila simulans.	hybrid females from drosophila simulans females x drosophila melanogaster males die as embryos while hybrid males from the reciprocal cross die as late larvae. the other two classes are sterile adults. letting c, x, and y designate egg cytoplasm, x, and y chromosomes, respectively, and subscripts m and s stand for melanogaster and simulans, cmxmys males are lethal in the larval stage and are rescued by the previously reported genes, lhr (lethal hybrid rescue) in simulans or hmr (hybrid male resc ...	1993	8436276
evidence for adaptive evolution of the g6pd gene in the drosophila melanogaster and drosophila simulans lineages.	proponents of the neutral theory argue that evolution at the molecular level largely reflects a process of random genetic drift of neutral mutations. under this theory, levels of interspecific divergence and intraspecific polymorphism are expected to be correlated across classes of nucleotide or amino acid sequences with different degrees of functional constraint, such as synonymous and replacement sites. nucleotide sites with reduced polymorphism should show comparably reduced levels of intersp ...	1993	8356041
noninvolvement of the long terminal repeat of transposable element 17.6 in insecticide resistance in drosophila.	waters and colleagues recently suggested [waters, l. c., zelhof, a. c., shaw, b. j. & ch'ang, l.-y. (1992) proc. natl. acad. sci. usa 89, 4855-4859] that an insertion of a long terminal repeat of transposable element 17.6 into the 3' untranslated region of a p450 gene leads to susceptibility to the insecticide ddt in drosophila melanogaster. we tested this hypothesis by screening lines from around the world and found that the presence or absence of a long terminal repeat was uncorrelated with re ...	1993	8390673
a single-amino acid substitution in a gamma-aminobutyric acid subtype a receptor locus is associated with cyclodiene insecticide resistance in drosophila populations.	resistance to cyclodiene insecticides, documented in at least 277 species, is perhaps the most common kind of resistance to any pesticide. by using cyclodiene resistance to localize the responsible gene, a gamma-aminobutyric acid type a receptor/chloride ion-channel gene was previously cloned and sequenced from an insecticide-susceptible drosophila melanogaster strain. we now describe the molecular genetics of the resistance allele. a single-base-pair mutation, causing a single-amino acid substi ...	1993	8095336
lack of correlation between interspecific divergence and intraspecific polymorphism at the suppressor of forked region in drosophila melanogaster and drosophila simulans.	levels of dna sequence polymorphism at the suppressor of forked [su(f)] region in natural populations of drosophila melanogaster and drosophila simulans are estimated by restriction map analysis. su(f) is located at the base of the euchromatic portion of the x chromosome where the level of crossing-over per physical length is extremely low. in a survey of 55 alleles from three natural populations of d. melanogaster, only 2 restriction sites of 27 hexanucleotide and 108 tetranucleotide restrictio ...	1993	8095333
analysis of drosophila chromosome 4 using pulsed field gel electrophoresis.	previous estimates of the size of drosophila melanogaster chromosome 4 have indicated that it is 1% to 4% of the genome or approximately 6 mb. we have used pulsed field gel electrophoresis (pfge) to separate megabase-sized molecules of d. melanogaster chromosomal dna. southern blots of these gels were probed with dna fragments from the cubitus interruptus and zfh-2 genes, which are located on chromosome 4. they each identify the same-sized distinct band that migrates at approximately 5.2 mb in d ...	1993	8149812
the genetics of an isolating mechanism between two sibling species of drosophila.	matings between drosophila simulans females and males of the sibling species d. mauritiana are of abnormally short duration. these rapid matings interrupt the transfer of sperm, leading to substantial reproductive isolation in interspecific as compared to intraspecific copulations. genetic analysis of this behavior shows that it is influenced much more by the male than the female genotype, with genes from d. simulans being dominant. in males, shortened copulation is caused by interspecific diver ...	1993	28567909
the effects of interspecific y chromosome replacements on hybrid sterility within the drosophila simulans clade.	we attempted to introgress y chromosomes between three sibling species of drosophila: d. simulans, d. sechellia and d. mauritiana. four d. sechellia y chromosomes were introgressed into d. simulans without loss of fertility whereas the four reciprocal introgressions (d. simulans y introgressed into d sechellia) all result in sterility. both reciprocal y introgressions of d. simulans and d. mauritiana (four of each) also result in sterility. compared with d. simulans males, the males with the d. ...	1993	8244006
genetic control of pheromones in drosophila simulans. ii. kété, a locus on the x chromosome.	the production of drosophila cuticular hydrocarbons, including contact pheromones, is under polygenic control. to investigate x-linked loci, ems mutations were induced in drosophila simulans flies. a mutant strain was discovered which in both sexes show a reduction in the biosynthesis of both 7-tricosene (7-t) the species contact pheromone and all other linear hydrocarbons. the locus controlling this effect, kété, is recessive and was localized to i, 18.5. unlike a previously identified gene on ...	1993	8454203
molecular polymorphism in the period gene of drosophila simulans.	the threonine-glycine (thr-gly) repeat region of the period (per) gene of eight natural populations of drosophila simulans from europe and north africa was analyzed by polymerase chain reaction, dna sequencing and heteroduplex formation. five different length alleles encoding 21, 23, 25 and two different kinds of 24 thr-gly pairs in the uninterrupted repeat were found. in the 3' region flanking the repeat 6 nucleotide substitutions (3 synonymous, 3 replacement) were observed in three different c ...	1994	7851767
nuclear background affects frequency dynamics of mitochondrial dna variants in drosophila simulans.	transplasmic lines, in which the original mitochondrial dna (mtdna) had been completely replaced by the mtdna of the donor, were constructed to test for selection on mtdna variants and to investigate the effects of nuclear-cytoplasmic interactions in drosophila simulans. these lines were used to set up 12 experimental populations putting in competition two mtdna variants with two different starting frequencies. population cages were maintained for 20 generations and periodically sampled to monit ...	1994	8056616
evolution of incompatibility-inducing microbes and their hosts.	in many insect species, males infected with microbes related to wolbachia pipientis are "incompatible" with uninfected females. crosses between infected males and uninfected females produce significantly fewer adult progeny than the other three possible crosses. the incompatibility-inducing microbes are usually maternally transmitted. thus, incompatibility tends to confer a reproductive advantage on infected females in polymorphic populations, allowing these infections to spread. this paper anal ...	1994	28568404
a multilevel approach to the significance of genetic variation in alcohol dehydrogenase of drosophila.	prior studies showed that differences in alcohol dehydrogenase (adh) activity across genotypes of drosophila are decisive for the outcome of selection by ethanol. in the present paper, the effect on adh activity and egg-to-adult survival of combinations of ethanol, propan-2-ol, and acetone in naturally occurring concentrations is examined. propan-2-ol is converted into acetone by adh in vitro. acetone is considered a competitive inhibitor of ethanol for the adh enzymes. the melanogaster-adh-s al ...	1994	28568248
meiosis in drosophila males. i. the question of separate conjunctive mechanisms for the xy and autosomal bivalents.	the conjunctive mechanism of the xy bivalent is believed to differ from that of the autosomal bivalents in the achiasmate drosophila melanogaster male. it has been proposed that hypothetical cohesive elements, termed collochores, hold the x and y chromosomes together at or near their nucleolar organizing regions (nors) and that collochores are not exhibited by autosomal bivalents. in electron micrographs, unique fibrillar material is observed between the x and y chromosomes at the synaptic site. ...	1994	7821091
genetic and maternal variation for heat resistance in drosophila from the field.	in drosophila, field heritability estimates have focused on morphological traits and ignored maternal effects. this study considers heritable variation and maternal effects in a physiological trait, heat resistance. drosophila were collected from the field in melbourne, australia. resistance was determined using knock-down time at 37 degrees. drosophila melanogaster was more resistant than drosophila simulans, and males tended to be more resistant than females. field heritability and maternal ef ...	1994	8088524
differences in p element population dynamics between the sibling species drosophila melanogaster and drosophila simulans.	patterns of p element establishment and evolution were compared in populations of d. melanogaster and d. simulans. for each species, mixed populations were initiated with m strain flies lacking p elements together with p strain flies having similar p element copy numbers and phenotypes. the mixed populations were subsequently maintained under similar environmental conditions. on the basis of gonadal sterility assays, p elements tended to be significantly more active in d. melanogaster than in d. ...	1994	8206365
the doc transposable element in drosophila melanogaster and drosophila simulans: genomic distribution and transcription.	the mobile element doc is similar in structure and coding potential to the line families found in various organisms. in this paper, we analyze the insertional and structural polymorphism of this element and show that it appears to have a long evolutionary history in the genome of d. melanogaster. like the family of i elements, the doc family seems to display three types of elements: full length elements, defective members that have recently transposed and long since immobilized members common to ...	1994	7813908
clonal analysis in hybrids between drosophila melanogaster and drosophila simulans.	we have analysed the viability of cellular clones induced by mitotic recombination in drosophila melanogaster/d. simulans hybrid females during larval growth. these clones contain a portion of either melanogaster or simulans genomes in homozygosity. analysis has been carried out for the x and the second chromosomes, as well as for the 3l chromosome arm. clones were not found in certain structures, and in others they appeared in a very low frequency. only in abdominal tergites was a significant n ...	1994	28305934
unraveling selection in the mitochondrial genome of drosophila.	we examine mitochondrial dna variation at the cytochrome b locus within and between three species of drosophila to determine whether patterns of variation conform to the predictions of neutral molecular evolution. the entire 1137-bp cytochrome b locus was sequenced in 16 lines of drosophila melanogaster, 18 lines of drosophila simulans and 13 lines of drosophila yakuba. patterns of variation depart from neutrality by several test criteria. analysis of the evolutionary clock hypothesis shows uneq ...	1994	7851772
neutral and non-neutral evolution of drosophila mitochondrial dna.	to test hypotheses of neutral evolution of mitochondrial dna (mtdna), nucleotide sequences were determined for 1515 base pairs of the nadh dehydrogenase subunit 5 (nd5) gene in the mitochondrial dna of 29 lines of drosophila melanogaster and 9 lines of its sibling species drosophila simulans. in contrast to the patterns for nuclear genes, where d. melanogaster generally exhibits much less nucleotide polymorphism, the number of segregating sites was slightly higher in a global sample of nine nd5 ...	1994	7851771
genetics of hybrid male sterility between drosophila sibling species: a complex web of epistasis is revealed in interspecific studies.	to study the genetic differences responsible for the sterility of their male hybrids, we introgressed small segments of an x chromosome from drosophila simulans into a pure drosophila mauritiana genetic background, then assessed the fertility of males carrying heterospecific introgressions of varying size. although this analysis examined less than 20% of the x chromosome (roughly 5% of the euchromatic portion of the d. simulans genome), and the segments were introgressed in only one direction, a ...	1994	7828817
evidence for complex genic interactions between conspecific chromosomes underlying hybrid female sterility in the drosophila simulans clade.	f1 hybrid females between the sibling species drosophila simulans, drosophila mauritiana and drosophila sechellia are completely fertile. however, we have found that female sterility can be observed in f2 backcross females who are homozygous for d. simulans x chromosomes and homozygous for autosomal regions from either d. mauritiana or d. sechellia. our results indicate that neither d. mauritiana autosome (2 or 3) can cause complete female sterility in a d. simulans background. the simultaneous ...	1994	8056310