| evolutionary conservation and molecular characteristics of repetitive sequences of drosophila koepferae. | thirteen middle repetitive dna clones obtained from the genome of drosophila koepferae have been tested for their evolutionary conservation in the other seven species of the buzzatii and martensis clusters (repleta group). all but two of these clones exhibit qualitatively similar patterns of hybridization in the eight species. the average interspecific hybridization signal is 85 per cent of that found intraspecifically, ranging from 73 to 93 per cent. partial sequencing of six of these clones ha ... | 1996 | 8626221 |
| a system of complementary genes in hybrids between drosophila koepferae and d. buzzatii: a markov chain model allows to make inferences about their number and relationships. | in backcrosses between d. koepferae and d. buzzatii, the disruption of a system of species-specific complementary factors brings about hybrid male inviability. this system consists of a lethal factor, hmi-1, linked to the x chromosome of d. koepferae, and several conspecific autosomal suppressors. however, hmi-1 hybrid males can also be rescued by factors present in some strains of d. buzzatii. the present work aims to estimate the number of hmi-1 suppressors in one of these strains by means of ... | 2001 | 11922103 |
| wing morphology and fluctuating asymmetry depend on the host plant in cactophilic drosophila. | as in most insect groups, host plant shifts in cactophilic drosophila represent environmental challenges as flies must adjust their developmental programme to the presence of different chemical compounds and/or to a microflora that may differ in the diversity and abundance of yeasts and bacteria. in this context, wing morphology provides an excellent opportunity to investigate the factors that may induce changes during development. in this work, we investigated phenotypic plasticity and developm ... | 2008 | 18081744 |
| interspecific hybridization increases transposition rates of osvaldo. | several authors have postulated that genetic divergence between populations could result in genomic incompatibilities that would cause an increase in transposition in their hybrids, producing secondary effects such as sterility and therefore starting a speciation process. it has been demonstrated that transposition largely depends on intraspecific hybridization for p, hobo, and i elements in drosophila melanogaster and for several elements, including long terminal repeat (ltr) and non-ltr retrot ... | 1999 | 10406110 |
| transposable element misregulation is linked to the divergence between parental pirna pathways in drosophila hybrids. | interspecific hybridization is a genomic stress condition that leads to the activation of transposable elements (tes) in both animals and plants. in hybrids between drosophila buzzatii and drosophila koepferae, mobilization of at least 28 tes has been described. however, the molecular mechanisms underlying this te release remain poorly understood. to give insight on the causes of this te activation, we performed a te transcriptomic analysis in ovaries (notorious for playing a major role in te si ... | 2017 | 28854624 |
| phenotypic plasticity in drosophila cactophilic species: the effect of competition, density, and breeding sites. | changes in the environmental conditions experienced by naturally occurring populations are frequently accompanied by changes in adaptive traits allowing the organism to cope with environmental unpredictability. phenotypic plasticity is a major aspect of adaptation and it has been involved in population dynamics of interacting species. in this study, phenotypic plasticity (i.e., environmental sensitivity) of morphological adaptive traits were analyzed in the cactophilic species drosophila buzzati ... | 2017 | 27061856 |
| drosophila females undergo genome expansion after interspecific hybridization. | genome size (or c-value) can present a wide range of values among eukaryotes. this variation has been attributed to differences in the amplification and deletion of different noncoding repetitive sequences, particularly transposable elements (tes). tes can be activated under different stress conditions such as interspecific hybridization events, as described for several species of animals and plants. these massive transposition episodes can lead to considerable genome expansions that could ultim ... | 2016 | 26872773 |
| changes of osvaldo expression patterns in germline of male hybrids between the species drosophila buzzatii and drosophila koepferae. | hybridization between different genomes is a source of genomic instability, sometimes associated with transposable element (te) mobilization. previous work showed that hybridization between the species drosophila buzzatii and drosophila koepferae induced mobilization of different (tes), the osvaldo retrotransposon being the most unstable. however, we ignore the mechanisms involved in this transposition release in interspecific hybrids. in order to disentangle the mechanisms involved in this proc ... | 2015 | 25711309 |
| interspecific hybridization as a genomic stressor inducing mobilization of transposable elements in drosophila. | transposable elements (tes) are dna sequences able to be mobilized in host genomes. they are currently recognized as the major mutation inducers because of their insertion in the target, their effect on neighboring regions, or their ectopic recombination. a large number of factors including chemical and physical factors as well as intraspecific crosses have traditionally been identified as inducers of transposition. besides environmental factors, interspecific crosses have also been proposed as ... | 2014 | 25136509 |
| genome-wide dissection of hybrid sterility in drosophila confirms a polygenic threshold architecture. | to date, different studies about the genetic basis of hybrid male sterility (hms), a postzygotic reproductive barrier thoroughly investigated using drosophila species, have demonstrated that no single major gene can produce hybrid sterility without the cooperation of several genetic factors. early work using hybrids between drosophila koepferae (dk) and drosophila buzzatii (db) was consistent with the idea that hms requires the cooperation of several genetic factors, supporting a polygenic thres ... | 2014 | 24489077 |
| multiple paternity and sperm competition in the sibling species drosophila buzzatii and drosophila koepferae. | sperm competition (sc) is a major component of sexual selection that enhances intra- and intersexual conflicts and may trigger rapid adaptive evolution of sexual characters. the actual role of sc on rapid evolution, however, is poorly understood. besides, the relative contribution of distinctive features of the mating system to among species variation in the strength of sc remains unclear. here, we assessed the strength of sc and mating system factors that may account for it in the closely relat ... | 2013 | 23952173 |
| inter and intraspecific variation in female remating propensity in the cactophilic sibling species drosophila buzzatii and d. koepferae. | post-mating sexual selection by means of sperm competition or cryptic female choice occurs in species in which females remate before exhausting sperm supplied by previous mates. thus, sperm competition is expected to be stronger when inseminated females remate more frequently or take longer to deplete sperm load. previous studies comparing oviposition behavior in the pair of closely related species drosophila buzzatii and drosophila koepferae suggest that inseminated females of the latter deplet ... | 2013 | 23542152 |
| aedeagal divergence in sympatric populations of two sibling species of cactophilic drosophila (diptera: drosophilidae): evidence of character displacement? | aedeagal morphology of two sibling cactophilic species, drosophila buzzatii patterson & wheeler and drosophila koepferae fontdevila & wasserman, was analyzed in nine allopatric and three sympatric locations throughout south america. morphological differences were detected for both aedeagus size and shape between sympatric and allopatric populations of d. buzzatii, despite the significant variability within both groups. populations of d. buzzatii sympatric with d. koepferae displayed smaller aede ... | 2012 | 23950045 |
| cloning and sequencing of the breakpoint regions of inversion 5g fixed in drosophila buzzatii. | chromosomal inversions are ubiquitous in drosophila both as intraspecific polymorphisms and interspecific differences. many gaps still remain in our understanding of the mechanisms that generate them. previous work has shown that in drosophila buzzatii, three polymorphic inversions were generated by ectopic recombination between copies of the transposon galileo. in this study, we have characterized the breakpoint regions of inversion 5g, fixed in d. buzzatii and absent in drosophila koepferae an ... | 2009 | 19198866 |
| molecular population genetics of the alpha-esterase5 gene locus in original and colonized populations of drosophila buzzatii and its sibling drosophila koepferae. | several studies have suggested that esterase-2 (est-2) may be the target of natural selection in the cactophilic fly drosophila buzzatii. in this work, we analyzed nucleotide variation in a fragment of alpha-esterase5 (alphae5), the gene encoding est-2, in original (argentinian) and colonized (australian) populations of d. buzzatii and in its sibling d. koepferae. estimates of nucleotide heterozygosity in d. buzzatii were similar in australia and argentina, although we detected a loss of singlet ... | 2007 | 17160646 |
| stable drosophila buzzatii-drosophila koepferae hybrids. | previous experiments discovered high rates of chromosomal rearrangements in the progeny of males containing a telomeric segment of drosophila koepferae in a d. buzzatii genetic background (segmental males). we have performed similar experiments, designed to test whether this chromosomal instability could be explained by a phenomenon similar to p-m hybrid dysgenesis or, alternatively, by a generalized telomeric effect. however, the results obtained have not allowed us to fully characterize this p ... | 2006 | 9703688 |
| the evolutionary history of d. buzzatii. xxii. chromosomal and genic sterility in male hybrids of drosophila buzzatii and drosophila koepferae. | the genetic basis of sterility in f1 male hybrids of drosophila buzzatii and d. koepferae has been investigated in two steps. (1) by successive backcrossing of hybrid females to either parental species. (2) by assessment of the effects on male fertility of selected segments of polytene chromosomes from the donor species on a background entirely derived from the recipient species. the length of introgressed segments producing sterility was progressively reduced through repeated backcrosses. this ... | 1991 | 2061093 |
| differences in tolerance to host cactus alkaloids in drosophila koepferae and d. buzzatii. | the evolution of cactophily in the genus drosophila was a major ecological transition involving over a hundred species in the americas that acquired the capacity to cope with a variety of toxic metabolites evolved as feeding deterrents in cactaceae. d. buzzatii and d. koepferae are sibling cactophilic species in the d. repleta group. the former is mainly associated with the relatively toxic-free habitat offered by prickly pears (opuntia sulphurea) and the latter has evolved the ability to use co ... | 2014 | 24520377 |
| characterization of gandalf, a new inverted-repeat transposable element of drosophila koepferae. | the cloning and characterization of gandalf, a new dna-transposing mobile element obtained from the drosophila koepferae (repleta group) genome is described. a fragment of gandalf was found in a middle repetitive clone that shows variable chromosomal localization. restriction, southern blot, pcr and sequencing analyses have shown that most gandalf copies are about 1 kb long, are flanked by 12 bp inverted terminal repeats and contain subterminal repetitive regions on both sides of the element. as ... | 1995 | 7565606 |