Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
|---|
| evolutionary history of the third chromosome gene arrangements of drosophila pseudoobscura inferred from inversion breakpoints. | the third chromosome of drosophila pseudoobscura is polymorphic for numerous gene arrangements that form classical clines in north america. the polytene salivary chromosomes isolated from natural populations revealed changes in gene order that allowed the different gene arrangements to be linked together by paracentric inversions representing one of the first cases where genetic data were used to construct a phylogeny. although the inversion phylogeny can be used to determine the relationships a ... | 2011 | 21339510 |
| determinants of synonymous and nonsynonymous variability in three species of drosophila. | we estimated the intensity of selection on preferred codons in drosophila pseudoobscura and d. miranda at x-linked and autosomal loci, using a published data set on sequence variability at 67 loci, by means of an improved method that takes account of demographic effects. we found evidence for stronger selection at x-linked loci, consistent with their higher levels of codon usage bias. the estimates of the strength of selection and mutational bias in favor of unpreferred codons were similar to th ... | 2011 | 21191087 |
| enrichment of mrna-like noncoding rnas in the divergence of drosophila males. | with the advent of transcriptome data, it has become clear that mrna-like noncoding rnas (mlncrnas) are widespread in eukaryotes. although their functions are poorly understood, these transcripts may play an important role in development and could thus be involved in determining developmental complexity and phenotypic diversification. however, few studies have assessed their potential roles in the divergence of closely related species. here, we identify and study patterns of sequence and express ... | 2010 | 21041796 |
| genetics of natural populations; experimental reproduction of some of the changes caused by natural selection in certain populations of drosophila pseudoobscura. | 1946 | 21021044 | |
| genetics of natural populations; recombination and variability in populations of drosophila pseudoobscura. | 1946 | 20985721 | |
| odorant receptor (or) genes: polymorphism and divergence in the d. melanogaster and d. pseudoobscura lineages. | in insects, like in most invertebrates, olfaction is the principal sensory modality, which provides animals with essential information for survival and reproduction. odorant receptors are involved in this response, mediating interactions between an individual and its environment, as well as between individuals of the same or different species. the adaptive importance of odorant receptors renders them good candidates for having their variation shaped by natural selection. | 2010 | 20967126 |
| spermatogenic cyst and organ culture in drosophila pseudoobscura. | spermatogenesis is a complex series of processes that involves (1) the maintenance of a renewable pool of diploid stem cells within a niche, (2) the mitotic expansion of a subpopulation of stem cells committed to the spermatogenic pathway, and (3) the differentiation of diploid cells into highly specialized, haploid spermatozoa through meiotic and post-meiotic cellular transformations. drosophila melanogaster is a desirable model for studying spermatogenesis, as similarities exist between mammal ... | 2010 | 20694478 |
| polyandry increases offspring viability and mother productivity but does not decrease mother survival in drosophila pseudoobscura. | polyandrous mating is common, but the benefits for females of polyandry remain controversial. to test whether mating with multiple males affects female fitness, we compared lifetime components of fitness of three experimental sets of drosophila pseudoobscura females: monogamous females allowed to copulate one time (moc); monogamous females held with a male over her entire life and experiencing many copulations (mmc); and polyandrous females with a different male over each day of their lives and ... | 2010 | 20643932 |
| evolution of expression patterns of two odorant-binding protein genes, obp57d and obp57e, in drosophila. | odorant-binding proteins (obps) function in the perception of chemical signals together with odorant and taste receptors. genes encoding obps form a large family in insect genomes. in drosophila, the evolution of obp gene repertoire has been well studied by comparisons of the whole genome sequences from 12 closely related species. in contrast, their expression patterns are known only in drosophila melanogaster. two obp genes, obp57d and obp57e, arose by gene duplication at the early stage of d. ... | 2010 | 20637846 |
| characterizing recurrent positive selection at fast-evolving genes in drosophila miranda and drosophila pseudoobscura. | characterizing the distribution of selection coefficients in natural populations remains a central challenge in evolutionary biology. we resequenced a subset of 19 fast-evolving protein-coding genes in the sister species drosophila miranda and d. pseudoobscura and their flanking regions to characterize the spatial footprint left by recurrent and recent selection. consistent with previous findings, fast-evolving genes and their flanking regions show reduced levels of neutral diversity compared wi ... | 2010 | 20624741 |
| adverse interactions between micro-rnas and target genes from different species. | it is commonly assumed but not proven that micrornas (mirnas) and their targets coevolve. under this assumption, mirnas and targets from different species may interact adversely, resulting in reduced fitness. however, the strength of the adverse interactions may not be detectable because even outright deletions of mirnas often manifest only subtle fitness effects. we tested and measured the strength of heterospecific interactions by carrying out transgenic experiments across drosophila species b ... | 2010 | 20615957 |
| estimating the parameters of selection on nonsynonymous mutations in drosophila pseudoobscura and d. miranda. | we present the results of surveys of diversity in sets of >40 x-linked and autosomal loci in samples from natural populations of drosophila miranda and d. pseudoobscura, together with their sequence divergence from d. affinis. mean silent site diversity in d. miranda is approximately one-quarter of that in d. pseudoobscura; mean x-linked silent diversity is about three-quarters of that for the autosomes in both species. estimates of the distribution of selection coefficients against heterozygous ... | 2010 | 20516497 |
| adaptive evolution of genes duplicated from the drosophila pseudoobscura neo-x chromosome. | drosophila x chromosomes are disproportionate sources of duplicated genes, and these duplications are usually the result of retrotransposition of x-linked genes to the autosomes. the excess duplication is thought to be driven by natural selection for two reasons: x chromosomes are inactivated during spermatogenesis, and the derived copies of retroposed duplications tend to be testis expressed. therefore, autosomal derived copies of retroposed genes provide a mechanism for their x-linked paralogs ... | 2010 | 20351054 |
| a complex suite of forces drives gene traffic from drosophila x chromosomes. | theoretical studies predict x chromosomes and autosomes should be under different selection pressures, and there should therefore be differences in sex-specific and sexually antagonistic gene content between the x and the autosomes. previous analyses have identified an excess of genes duplicated by retrotransposition from the x chromosome in drosophila melanogaster. a number of hypotheses may explain this pattern, including mutational bias, escape from x-inactivation during spermatogenesis, and ... | 2009 | 20333188 |
| genetics of natural populations; a response of certain gene arrangements in the third chromosome of drosophila pseudoobscura to natural selection. | 1947 | 20292738 | |
| effectiveness of intraspecific and interspecific matings in drosophila pseudoobscura and drosophila persimilis. | 2015 | 20286615 | |
| genetics of natural populations; rate of diffusion of a mutant gene through a population of drosophila pseudoobscura. | 1947 | 20244463 | |
| fish mapping of microsatellite loci from drosophila subobscura and its comparison to related species. | microsatellites are highly polymorphic markers that are distributed through all the genome being more abundant in non-coding regions. whether they are neutral or under selection, these markers if localized can be used as co-dominant molecular markers to explore the dynamics of the evolutionary processes. their cytological localization can allow identifying genes under selection, inferring recombination from a genomic point of view, or screening for the genomic reorganizations occurring during th ... | 2010 | 20198419 |
| polyandry prevents extinction. | females of most animal species are polyandrous, with individual females usually mating with more than one male. however, the ubiquity of polyandry remains enigmatic because of the potentially high costs to females of multiple mating. current theory to account for the high prevalence of polyandry largely focuses on its benefits to individual females. there are also higher-level explanations for the high incidence of polyandry-polyandrous clades may speciate more rapidly. here we test the hypothes ... | 2010 | 20188561 |
| translocation of y-linked genes to the dot chromosome in drosophila pseudoobscura. | one of the most striking cases of sex chromosome reorganization in drosophila occurred in the lineage ancestral to drosophila pseudoobscura, where there was a translocation of y-linked genes to an autosome. these genes went from being present only in males, never recombining, and having an effective population size of 0.5n to a state of autosomal linkage, where they are passed through both sexes, may recombine, and their effective population size has quadrupled. these genes appear to be function ... | 2010 | 20147437 |
| in vivo rnai rescue in drosophila melanogaster with genomic transgenes from drosophila pseudoobscura. | systematic, large-scale rna interference (rnai) approaches are very valuable to systematically investigate biological processes in cell culture or in tissues of organisms such as drosophila. a notorious pitfall of all rnai technologies are potential false positives caused by unspecific knock-down of genes other than the intended target gene. the ultimate proof for rnai specificity is a rescue by a construct immune to rnai, typically originating from a related species. | 2010 | 20126626 |
| the quantitative genetics and coevolution of male and female reproductive traits. | studies of experimental sexual selection have tested the effect of variation in the intensity of sexual selection on male investment in reproduction, particularly sperm. however, in several species, including drosophila pseudoobscura, no sperm response to experimental evolution has occurred. here, we take a quantitative genetics approach to examine whether genetic constraints explain the limited evolutionary response. we quantified direct and indirect genetic variation, and genetic correlations ... | 2010 | 20100215 |
| the "plant drosophila": e.b. babcock, the genus "crepis," and the evolution of a genetics research program at berkeley, 1915-1947. | this paper explores the research and administrative efforts of ernest brown babcock, head of the division of genetics in the college of agriculture at the university of california, berkeley, the first academic unit so named in the united states. it explores the rationale for his choice of "model organism," the development--and transformation--of his ambitious genetics research program centering on the weedy plant genus named "crepis" (commonly known as the hawkbeard), along with examining in det ... | 2009 | 20077617 |
| increased opportunity for sexual conflict promotes harmful males with elevated courtship frequencies. | mating systems have a profound influence on the probability of conflict occurring between the sexes. promiscuity is predicted to generate sexual conflict, thereby driving the evolution of male traits that harm females, whereas monogamy is expected to foster reproductive cooperation, thus rendering such traits redundant. we tested these predictions using experimentally evolved drosophila pseudoobscura subject to different mating systems. female survival was not influenced by the mating system tre ... | 2010 | 20039999 |
| sex ratio drive promotes sexual conflict and sexual coevolution in the fly drosophila pseudoobscura. | selfish genetic elements occur in all living organisms and often cause reduced fertility and sperm competitive ability in males. in the fruit fly drosophila pseudoobscura, the presence of a sex-ratio distorting x-chromosome meiotic driver sex ratio (sr) has been shown to promote the evolution of increased female remating rates in laboratory populations. this is favored because it promotes sperm competition, which decreases the risk to females of producing highly female-biased broods and to their ... | 2010 | 19922445 |
| patterns of dna-sequence divergence between drosophila miranda and d. pseudoobscura. | contrary to the classical view, a large amount of non-coding dna seems to be selectively constrained in drosophila and other species. here, using drosophila miranda bac sequences and the drosophila pseudoobscura genome sequence, we aligned coding and non-coding sequences between d. pseudoobscura and d. miranda, and investigated their patterns of evolution. we found two patterns that have previously been observed in comparisons between drosophila melanogaster and its relatives. first, there is a ... | 2009 | 19859648 |
| evolution of sex-dependent gene expression in three recently diverged species of drosophila. | sexual dimorphism in morphological, physiological, and behavioral traits is pervasive in animals, as is the observation of strong sexual dimorphism in genomewide patterns of gene expression in the few species where this has been studied. studies of transcriptome divergence show that most interspecific transcriptional divergence is highly sex dependent, an observation consistent with the action of sex-dependent natural selection during species divergence. however, few transcriptome evolution stud ... | 2009 | 19720861 |
| epistasis modifies the dominance of loci causing hybrid male sterility in the drosophila pseudoobscura species group. | speciation, the evolution of reproductive isolation between populations, serves as the driving force for generating biodiversity. postzygotic barriers to gene flow, such as f(1) hybrid sterility and inviability, play important roles in the establishment and maintenance of biological species. f(1) hybrid incompatibilities in taxa that obey haldane's rule, the observation that the heterogametic sex suffers greater hybrid fitness problems than the homogametic sex, are thought to often result from i ... | 2009 | 19686263 |
| the insect chemoreceptor superfamily in drosophila pseudoobscura: molecular evolution of ecologically-relevant genes over 25 million years. | the insect chemoreceptor superfamily, consisting of the odorant receptor (or) and gustatory receptor (gr) families, exhibits patterns of evolution ranging from highly conserved proteins to lineage-specific gene subfamily expansions when compared across insect suborders and orders. here their evolution across the timespan of 25 million years is examined which yield orthologous divergences ranging from 5-50%. they also reveal the beginnings of lineage-specific gene subfamilies as multiple duplicat ... | 0 | 19613461 |
| the genomics of speciation in drosophila: diversity, divergence, and introgression estimated using low-coverage genome sequencing. | in nature, closely related species may hybridize while still retaining their distinctive identities. chromosomal regions that experience reduced recombination in hybrids, such as within inversions, have been hypothesized to contribute to the maintenance of species integrity. here, we examine genomic sequences from closely related fruit fly taxa of the drosophila pseudoobscura subgroup to reconstruct their evolutionary histories and past patterns of genic exchange. partial genomic assemblies were ... | 2009 | 19578407 |
| molecular evolution of a drosophila homolog of human brca2. | the human cancer susceptibility gene, brca2, functions in double-strand break repair by homologous recombination, and it appears to function via interaction of a repetitive region ("brc repeats") with rad-51. a putatively simpler homolog, dmbrca2, was identified in drosophila melanogaster recently and also affects mitotic and meiotic double-strand break repair. in this study, we examined patterns of repeat variation both within drosophila pseudoobscura and among available drosophila genome seque ... | 2009 | 19554456 |
| evolutionary dynamics of recently duplicated genes: selective constraints on diverging paralogs in the drosophila pseudoobscura genome. | duplicated genes produce genetic variation that can influence the evolution of genomes and phenotypes. in most cases, for a duplicated gene to contribute to evolutionary novelty it must survive the early stages of divergence from its paralog without becoming a pseudogene. i examined the evolutionary dynamics of recently duplicated genes in the drosophila pseudoobscura genome to understand the factors affecting these early stages of evolution. paralogs located in closer proximity have higher sequ ... | 2009 | 19536449 |
| a test and review of the role of effective population size on experimental sexual selection patterns. | experimental evolution, particularly experimental sexual selection in which sexual selection strength is manipulated by altering the mating system, is an increasingly popular method for testing evolutionary theory. concerns have arisen regarding genetic diversity variation across experimental treatments: differences in the number and sex ratio of breeders (effective population size; n(e)) and the potential for genetic hitchhiking, both of which may cause different levels of genetic variation bet ... | 2009 | 19473403 |
| a toolkit for high-throughput, cross-species gene engineering in drosophila. | we generated two complementary genomic fosmid libraries for drosophila melanogaster and drosophila pseudoobscura that permit seamless modification of large genomic clones by high-throughput recombineering and direct transgenesis. the fosmid transgenes recapitulated endogenous gene expression patterns. these libraries, in combination with recombineering technology, will be useful to rescue mutant phenotypes, allow imaging of gene products in living flies and enable systematic analysis and manipul ... | 2009 | 19465918 |
| origin and evolution of y chromosomes: drosophila tales. | classically, y chromosomes are thought to originate from x chromosomes through a process of degeneration and gene loss. now, the availability of 12 drosophila genomes provides an opportunity to study the origin and evolution of y chromosomes in an informative phylogenetic context. surprisingly, the majority of drosophila y-linked genes are recent acquisitions from autosomes and y chromosome gene gains are more frequent than gene losses. moreover, the drosophila pseudoobscura y chromosome lacks h ... | 2009 | 19443075 |
| the insect snmp gene family. | snmps are membrane proteins observed to associate with chemosensory neurons in insects; in drosophila melanogaster, snmp1 has been shown to be essential for the detection of the pheromone cis-vaccenyl acetate (cva). snmps are one of three insect gene clades related to the human fatty acid transporter cd36. we previously characterized the cd36 gene family in 4 insect orders that effectively cover the holometabola, or some 80% of known insect species and the 300 million years of evolution since th ... | 2009 | 19364529 |
| repeat mediated gene duplication in the drosophila pseudoobscura genome. | genetic mutations can occur on a wide variety of scales, including those that change single nucleotides, those that add or remove content to/from a genome, and those that change the organization of a genome. gene duplications are a specific class of mutations that add content to a genome, and they can arise via a wide variety of mechanisms. i examined the mechanisms responsible for recently duplicated genes in the d. pseudoobscura genome, and i observed both retroposed and dna duplications. many ... | 2009 | 19272434 |
| experimental manipulation of sexual selection promotes greater male mating capacity but does not alter sperm investment. | sexual selection theory makes clear predictions regarding male spermatogenic investment. to test these predictions we used experimental sexual selection in drosophila pseudoobscura, a sperm heteromorphic species in which males produce both fertile and sterile sperm, the latter of which may function in postmating competition. specifically, we determined whether the number and size of both sperm types, as well as relative testis mass and accessory gland size, increased with increased sperm competi ... | 2009 | 19236477 |
| a single gene causes both male sterility and segregation distortion in drosophila hybrids. | a central goal of evolutionary biology is to identify the genes and evolutionary forces that cause speciation, the emergence of reproductive isolation between populations. despite the identification of several genes that cause hybrid sterility or inviability-many of which have evolved rapidly under positive darwinian selection-little is known about the ecological or genomic forces that drive the evolution of postzygotic isolation. here, we show that the same gene, overdrive, causes both male ste ... | 2009 | 19074311 |
| a multispecies approach for comparing sequence evolution of x-linked and autosomal sites in drosophila. | population genetics models show that, under certain conditions, the x chromosome is expected to be under more efficient selection than the autosomes. this could lead to 'faster-x evolution', if a large proportion of mutations are fixed by positive selection, as suggested by recent studies in drosophila. we used a multispecies approach to test this: muller's element d, an autosomal arm, is fused to the ancestral x chromosome in drosophila pseudoobscura and its sister species, drosophila affinis. ... | 2008 | 19061532 |
| selfish genetic elements promote polyandry in a fly. | it is unknown why females mate with multiple males when mating is frequently costly and a single copulation often provides enough sperm to fertilize all a female's eggs. one possibility is that remating increases the fitness of offspring, because fertilization success is biased toward the sperm of high-fitness males. we show that female drosophila pseudoobscura evolved increased remating rates when exposed to the risk of mating with males carrying a deleterious sex ratio-distorting gene that als ... | 2008 | 19023079 |
| studies on sex-ratio in drosophila pseudoobscura; selection and sex-ratio. | 1948 | 18884662 | |
| observations on the mating behavior of drosophila pseudoobscura and d. persimilis. | 1948 | 18884172 | |
| adaptive properties of carriers of certain gene arrangements in drosophila pseudoobscura. | 1948 | 18863985 | |
| selection in heterogeneous environments maintains the gene arrangement polymorphism of drosophila pseudoobscura. | chromosomal rearrangements may play an important role in how populations adapt to a local environment. the gene arrangement polymorphism on the third chromosome of drosophila pseudoobscura is a model system to help determine the role that inversions play in the evolution of this species. the gene arrangements are the likely target of strong selection because they form classical clines across diverse geographic habitats, they cycle in frequency over seasons, and they form stable equilibria in pop ... | 2008 | 18764919 |
| developmental stage and level of codon usage bias in drosophila. | codon usage bias (cub) is a ubiquitous observation in molecular evolution. as a model, drosophila has been particularly well-studied and indications show that selection at least partially controls codon usage, probably through selection for translational efficiency. although many aspects of drosophila cub have been studied, this is the first study relating codon usage to development in this holometabolous insect with very different life stages. here we ask the question: what developmental stage ... | 2008 | 18755761 |
| failure to replicate two mate preference qtls across multiple strains of drosophila pseudoobscura. | behavioral genetic mapping studies in model organisms predominantly use crosses originating from a single pair of inbred lines to determine the location of alleles that confer genetic variation in the trait of interest, and they often make sweeping generalizations about the genetic architecture of the trait based on these results. a previous study fine mapped mate preference variation between one pair of drosophila pseudoobscura lines and identified 2 strong-effect behavioral quantitative trait ... | 2017 | 18728083 |
| fine-scale mapping of recombination rate in drosophila refines its correlation to diversity and divergence. | regional rates of recombination often correlate with levels of nucleotide diversity, and either selective or neutral hypotheses can explain this relationship. regional recombination rates also correlate with nucleotide differences between human and chimpanzee, consistent with models where recombination is mutagenic; however, a lack of correlation is observed in the drosophila melanogaster group, consistent with models invoking natural selection. here, we revisit the relationship among recombinat ... | 2008 | 18621713 |
| molecular evolution of drosophila cdc6, an essential dna replication-licensing gene, suggests an adaptive choice of replication origins. | increased size of eukaryotic genomes necessitated the use of multiple origins of dna replication, and presumably selected for their efficient spacing to ensure rapid dna replication. the sequence of these origins remains undetermined in metazoan genomes, leaving important questions about the selective constraints acting on replication origins unanswered. we have chosen to study the evolution of proteins that recognize and define these origins every cell cycle, as a surrogate to the direct analys ... | 0 | 18618020 |
| male-biased genes are overrepresented among novel drosophila pseudoobscura sex-biased genes. | the origin of functional innovation is among the key questions in biology. recently, it has been shown that new genes could arise from non-coding dna and that such novel genes are often involved in male reproduction. | 2008 | 18577217 |
| sexual selection and interacting phenotypes in experimental evolution: a study of drosophila pseudoobscura mating behavior. | sexual selection requires social interactions, particularly between the sexes. when trait expression is influenced by social interactions, such traits are called interacting phenotypes and only recently have the evolutionary consequences of interacting phenotypes been considered. here we investigated how variation in relative fitness, or the opportunity for sexual selection, affected the evolutionary trajectories of interacting phenotypes. we used experimentally evolved populations of the natura ... | 2008 | 18410532 |
| sex ratio distorter reduces sperm competitive ability in an insect. | selfish genetic elements (sges) are ubiquitous in animals and often associated with low male fertility due to reduced sperm number in male carriers. in the fruit fly drosophila pseudoobscura, the meiotic driving x chromosome "sex ratio" kills y-bearing sperm in carrier males (sr males), resulting in female only broods. we competed sr males against the ejaculates of noncarrying standard males (st males), and quantified the number of sperm transferred by sr and st males to females. we show that sr ... | 2008 | 18373627 |
| evolutionary biology: sterile saviours. | sterile sperm castes are widespread, but their significance remains enigmatic. new experiments on drosophila pseudoobscura reveal that sterile sperm may promote the survival of fertilising sperm inside the spermicidal female reproductive tract. | 2008 | 18364233 |
| an intron loss of dfak gene in species of the drosophila melanogaster subgroup and phylogenetic analysis. | drosophila focal adhesion kinase (dfak) gene is a single-copy nuclear gene. previous study revealed that drosophila melanogaster and drosophila simulans had lost an intron precisely within the tyrosine kinase (tyk) domain of this gene. however, this did not happen in several other drosophila species, including drosophila elegans, drosophila ficusphila, drosophila biarmipes, drosophila jambulina, drosophila prostipennis, drosophila takahashii, and drosophila pseudoobscura. in the current study, h ... | 2009 | 18310070 |
| a sterile sperm caste protects brother fertile sperm from female-mediated death in drosophila pseudoobscura. | spermicide (i.e., female-mediated sperm death) is an understudied but potentially widespread phenomenon that has important ramifications for the study of sexual conflict, postcopulatory sexual selection, and fertility [1, 2]. males are predicted to evolve adaptations against spermicide, but few antispermicidal mechanisms have been definitively identified. one such adaptation may be the enigmatic infertile sperm morphs or "parasperm" produced by many species, which have been hypothesized to prote ... | 2008 | 18291649 |
| figaro: a novel statistical method for vector sequence removal. | sequences produced by automated sanger sequencing machines frequently contain fragments of the cloning vector on their ends. software tools currently available for identifying and removing the vector sequence require knowledge of the vector sequence, specific splice sites and any adapter sequences used in the experiment-information often omitted from public databases. furthermore, the clipping coordinates themselves are missing or incorrectly reported. as an example, within the approximately 1.2 ... | 2008 | 18202027 |
| genetics of natural populations; experiments on chromosomes of drosophila pseudoobscura from different geographic regions. | 1948 | 18100290 | |
| genetics of natural populations; proof of operation of natural selection in wild populations of drosophila pseudoobscura. | 1948 | 18100287 | |
| divergence between the drosophila pseudoobscura and d. persimilis genome sequences in relation to chromosomal inversions. | as whole-genome sequence assemblies accumulate, a challenge is to determine how these can be used to address fundamental evolutionary questions, such as inferring the process of speciation. here, we use the sequence assemblies of drosophila pseudoobscura and d. persimilis to test hypotheses regarding divergence with gene flow. we observe low differentiation between the two genome sequences in pericentromeric and peritelomeric regions. we interpret this result as primarily a remnant of the correl ... | 2007 | 18039875 |
| global patterns of sequence evolution in drosophila. | sequencing of the genomes of several drosophila allows for the first precise analyses of how global sequence patterns change among multiple, closely related animal species. a basic question is whether there are characteristic features that differentiate chromosomes within a species or between different species. | 2007 | 17996078 |
| evolutionary dynamics of eukaryotic selenoproteomes: large selenoproteomes may associate with aquatic life and small with terrestrial life. | selenocysteine (sec) is a selenium-containing amino acid that is co-translationally inserted into nascent polypeptides by recoding uga codons. selenoproteins occur in both eukaryotes and prokaryotes, but the selenoprotein content of organisms (selenoproteome) is highly variable and some organisms do not utilize sec at all. | 2007 | 17880704 |
| sexual conflict does not drive reproductive isolation in experimental populations of drosophila pseudoobscura. | sexual conflict has been predicted to drive reproductive isolation by generating arbitrary but rapid coevolutionary changes in reproductive traits among allopatric populations. a testable prediction of this proposal is that allopatric populations experiencing different levels of sexual conflict should exhibit different levels of reproductive isolation. we tested this prediction using experimentally evolved populations of the promiscuous drosophila pseudoobscura. we manipulated sexual conflict by ... | 2007 | 17714294 |
| the drosulfakinin 0 (dsk 0) peptide encoded in the conserved dsk gene affects adult drosophila melanogaster crop contractions. | we report that the drosulfakinin 0 (dsk 0; nqktmsfnh2) structure and genomic organization are conserved. the dsk 0 c-terminus, sfnh2, is widely distributed in the animal kingdom suggesting it defines a novel peptide family. we also report the first description of dsk 0 activity. dsk 0, i (dsk i, fddyghmrfnh2), and ii (dsk ii, ggddqfddyghmrfnh2) are encoded in sulfakinin (dsk). drosophila erecta, drosophila sechellia, drosophila simulans, and drosophila yakuba shared 62.5-87.5% identity to drosop ... | 2007 | 17632121 |
| meiotic transmission of drosophila pseudoobscura chromosomal arrangements. | drosophila pseudoobscura harbors a rich gene arrangement polymorphism on the third chromosome generated by a series of overlapping paracentric inversions. the arrangements suppress recombination in heterokaryotypic individuals, which allows for the selective maintenance of coadapted gene complexes. previous mapping experiments used to determine the degree to which recombination is suppressed in gene arrangement heterozygotes produced non-recombinant progeny in non-mendelian ratios. the deviation ... | 2007 | 17565383 |
| techniques for multi-genome synteny analysis to overcome assembly limitations. | genome scale synteny analysis, the analysis of relative gene-order conservation between species, can provide key insights into evolutionary chromosomal dynamics, rearrangement rates between species, and speciation analysis. with the rapid availability of multiple genomes, there is a need for efficient solutions to aid in comparative syntenic analysis. current methods rely on homology assessment and multiple alignment based solutions to determine homologs of genetic markers between species and to ... | 2006 | 17503388 |
| experimental constraints on mate preferences in drosophila pseudoobscura decrease offspring viability and fitness of mated pairs. | using drosophila pseudoobscura, we tested the hypothesis that social constraints on the free expression of mate preferences, by both females and males, decrease offspring viability and reproductive success of mating pairs. mate preference arenas eliminated intrasexual combat and intersexual coercion. the time female and male choosers spent in arena tests near either of two opposite-sex individuals measured the preferences of choosers. we placed choosers in breeding trials with their preferred or ... | 2007 | 17360550 |
| evolution of sex chromosomes: dosage compensation of the lcp1-4 gene cluster on the evolving neo-x chromosome in drosophila miranda. | in drosophila miranda the small multigene family of the larval cuticle protein (lcp1-4) genes resides on the evolving neo-x and neo-y sex chromosome pair while in the sibling species drosophila pseudoobscura and drosophila persimilis the gene cluster is inherited autosomally. the neo-y chromosomal lcp1, lcp2 and lcp4 genes are, as previously shown by us, not expressed and only lcp3 is expressed at a strongly reduced level. as a first step in understanding the evolutionary mechanism(s) transformi ... | 2007 | 17352708 |
| a short note on short dispersal events. | we study how the speed of spread for an integrodifference equation depends on the dispersal pattern of individuals. when the dispersal kernel has finite variance, the central limit theorem states that convolutions of the kernel with itself will approach a suitably chosen gaussian distribution. despite this fact, the speed of spread cannot be obtained from the gaussian approximation. we give several examples and explanations for this fact. we then use the kurtosis of the kernel to derive an impro ... | 2007 | 17318675 |
| 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 ... | 1980 | 17249004 |
| 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 ... | 1979 | 17248966 |
| 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 ... | 1978 | 17248849 |
| 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 ... | 1977 | 17248785 |
| 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 ... | 1977 | 17248784 |
| 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 ... | 1977 | 17248769 |
| 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. | 1977 | 17248768 |
| 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 ... | 1977 | 17248763 |
| 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 ... | 1977 | 17248755 |
| 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 ... | 1977 | 17248754 |
| 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 ... | 1977 | 17248742 |
| morphological differences between drosophila pseudoobscura populations selected for opposite geotaxes and phototaxes. | 1969 | 17248462 | |
| factors determining rates of the evolution of fitness in laboratory populations of drosophila pseudoobscura. | 1969 | 17248453 | |
| mating control by gene arrangements in drosophila pseudoobscura. | 1966 | 17248341 | |
| sex-linked inheritance of a quantitative trait of drosophila pseudoobscura. | 1963 | 17248170 | |
| genetic potential for an extra crossvein in drosophila pseudoobscura. | 1963 | 17248168 | |
| a comparison of purebred and crossbred selection schemes with two populations of drosophila pseudoobscura. | 1963 | 17248144 | |
| genetics of natural populations. xxix. is the genetic load in drosophila pseudoobscura a mutational or a balanced load? | 1960 | 17247959 | |
| genetics of natural populations. xxviii. the magnitude of the genetic load in populations of drosophila pseudoobscura. | 1960 | 17247958 | |
| effect of environment upon the manifestation of heterosis and homeostasis in drosophila pseudoobscura. | 1959 | 17247854 | |
| release of genetic variability through recombination. i. drosophila pseudoobscura. | 1958 | 17247800 | |
| selection for developmental rate in drosophila pseudoobscura. | 1958 | 17247740 | |
| genotypic background and heterosis in drosophila pseudoobscura. | 1955 | 17247594 | |
| genetics of natural populations. xxiv. developmental homeostasis in natural populations of drosophila pseudoobscura. | 1955 | 17247591 | |
| genetics of natural populations. xxiii. biological role of deleterious recessives in populations of drosophila pseudoobscura. | 1955 | 17247590 | |
| variable crossing over arising in different strains of drosophila pseudoobscura. | 1955 | 17247560 | |
| rates of spontaneous mutation in the second chromosomes of the sibling species, drosophila pseudoobscura and drosophila persimilis. | 1954 | 17247527 | |
| the genotypic control of crossing over in drosophila pseudoobscura. | 1954 | 17247512 | |
| heterosis and the integration of the genotype in geographic populations of drosophila pseudoobscura. | 1954 | 17247469 | |
| genetics of sexual isolation between drosophila pseudoobscura and drosophila persimilis. | 1946 | 17247220 | |
| genetics of natural populations. xi. manifestation of genetic variants in drosophila pseudoobscura in different environments. | 1944 | 17247121 | |
| genetics of natural populations. x. dispersion rates in drosophila pseudoobscura. | 1943 | 17247091 |