| reproductive relationships and degree of synapsis in the polytene chromosomes of the drosophila buzzatii species cluster. | the process of speciation occurs through the evolution of any of several forms of reproductive isolation between taxa, including inviability of hybrids. in this work, strains derived from allopatric populations of drosophila buzzatii cluster species were experimentally crossed in order to evaluate their reproductive and cytogenetic relationships, and to contribute toward understanding the reproductive isolation in this group of sibling species. although intrastrain crosses were highly fertile, w ... | 2006 | 16710520 |
| phylogeny and molecular evolution of the drosophila hydei subgroup (drosophila repleta group) inferred from the xanthine dehydrogenase gene. | the hydei subgroup (drosophila repleta group) consists of seven species divided into two complexes: bifurca and hydei, whose phylogenetic relationships are not well understood. to evaluate the molecular phylogeny of this subgroup, we analyzed 2085 bp of coding sequence of the xanthine dehydrogenase gene in six available species of the hydei subgroup, with drosophila buzzatii and drosophila mulleri as an outgroup. for phylogenetic reconstruction we adopted a maximum-likelihood framework, based on ... | 2005 | 15935705 |
| a bac-based physical map of the drosophila buzzatii genome. | large-insert genomic libraries facilitate cloning of large genomic regions, allow the construction of clone-based physical maps, and provide useful resources for sequencing entire genomes. drosophila buzzatii is a representative species of the repleta group in the drosophila subgenus, which is being widely used as a model in studies of genome evolution, ecological adaptation, and speciation. we constructed a bacterial artificial chromosome (bac) genomic library of d. buzzatii using the shuttle v ... | 2005 | 15930498 |
| molecular characterization and chromosomal distribution of galileo, kepler and newton, three foldback transposable elements of the drosophila buzzatii species complex. | galileo is a foldback transposable element that has been implicated in the generation of two polymorphic chromosomal inversions in drosophila buzzatii. analysis of the inversion breakpoints led to the discovery of two additional elements, called kepler and newton, sharing sequence and structural similarities with galileo. here, we describe in detail the molecular structure of these three elements, on the basis of the 13 copies found at the inversion breakpoints plus 10 additional copies isolated ... | 2005 | 15695364 |
| on the pbum189 satellite dna variability among south american populations of drosophila buzzatii. | the pbum189 satellite dna was analysed in drosophila buzzatii populations that cover most of the species distribution in south america. this satdna consists of a + t-rich monomers of 189 bp and previous studies showed a fast rate of evolutionary change of this component of d. buzzatii genome. a total of 63 pbum189 repetition units from 14 d. buzzatii populations (9 from brazil and 5 from argentina) were studied. the average nucleotide variability among the 63 repeats is 4.2 %. at least one repea ... | 2003 | 15061796 |
| remating and sperm displacement in a natural population of drosophila buzzatii inferred from mother-offspring analysis of microsatellite loci. | prospects for estimation of parameters of models of sperm competition from field data have improved recently with the development of methods that employ multilocus genotype data from brood-structured samples. sperm competition in drosophila buzzatii is of special interest because it is possible to directly observe the breeding behaviour of this species in its natural habitat of rotting cactus. previous laboratory experiments showed that this species exhibits an unusual pattern of frequent remati ... | 2004 | 15009271 |
| heat and cold-induced male sterility in drosophila buzzatii: genetic variation among populations for the duration of sterility. | here we studied three phenotypic traits in drosophila buzzatii that are strongly effected by temperature, and are expected to be closely associated with fitness in nature. the traits measured were thermal threshold of male sterility, time for males to gain fertility when reared at a sterility-inducing temperature and transferred to 25 degrees c on eclosion and survival after development. the last two traits were measured under four temperature regimes, constant 12 degrees c, 25 degrees c, 31 deg ... | 2004 | 14679393 |
| chromosomal inversions effect body size and shape in different breeding resources in drosophila buzzatii. | the cactophilic drosophila buzzatii provides an excellent model for the study of reaction norms across discrete environments because it breeds on rotting tissues (rots) of very different cactus species. here we test the possible effects of second chromosome inversions on body size and shape (wing loading) across suitable natural breeding substrates. using homokaryotypic stocks derived from several lines homozygous for four naturally occurring chromosomal inversions, we show that arrangements sig ... | 2003 | 12815453 |
| the evolutionary history of drosophila buzzatii. xxxv. inversion polymorphism and nucleotide variability in different regions of the second chromosome. | inversions are portions of a chromosome where the gene order is reversed relative to a standard reference orientation. because of reduced levels of recombination in heterokaryotypes, inversions have a potentially important effect on patterns of nucleotide variability in those genomic regions close to, or included in, the inverted fragments. here we report sequence variation at three anonymous regions (stss) located at different positions in relation to second-chromosome inversion breakpoints in ... | 2003 | 12716995 |
| the foldback-like transposon galileo is involved in the generation of two different natural chromosomal inversions of drosophila buzzatii. | chromosomal inversions are the most common type of genome rearrangement in the genus drosophila. although the potential of transposable elements (tes) for generating inversions has been repeatedly demonstrated in the laboratory, little is known on their role in the generation of natural inversions, which are those effectively contributing to the adaptation and/or evolution of species. we have cloned and sequenced the two breakpoints of the polymorphic inversion 2q7 of d. buzzatii. the sequence a ... | 2003 | 12679549 |
| transpecific polymorphisms in an inversion linked esterase locus in drosophila buzzatii. | nucleotide variation was studied in a 1.1 kb section of the coding region of an esterase gene (est-a) that maps in the center of the segments rearranged by polymorphic inversions in the cactophilic drosophila buzzatii. we examine 30 homozygous second-chromosome lines differing in gene arrangement and three d. koepferae isofemale lines as outgroups. our data show that est-a is a highly polymorphic gene at both synonymous and replacement sites. significant departures from homogeneity in the distri ... | 2003 | 12644562 |
| direct and correlated responses to artificial selection on developmental time and wing length in drosophila buzzatii. | developmental time and body size are two positively correlated traits closely related to fitness in many organisms including drosophila. previous work suggested that these two traits are involved in a trade-off that may result from a negative genetic correlation between their effects on pre-adult and adult fitness. here, we examine the evolution of developmental time and body size (indexed by wing length) under artificial selection applied to one or both traits in replicated d. buzzatii populati ... | 2002 | 12583594 |
| genetic variation in original and colonizing drosophila buzzatii populations analysed by microsatellite loci isolated with a new pcr screening method. | a new polymerase chain reaction-based screening method for microsatellites is presented. using this method, we isolated 12 microsatellite loci from drosophila buzzatii, two of which were x-linked. we applied the other 10 microsatellite loci to the analysis of genetic variation in five natural populations of d. buzzatii. two populations were from the species' original distribution in argentina, whereas the other three were from europe (two) and australia that were colonized 200 and 65 years ago, ... | 2002 | 11856420 |
| oviposition acceptance and fecundity schedule in the cactophilic sibling species drosophila buzzatii and d. koepferae on their natural hosts. | we tested for the occurrence of oviposition acceptance for different media prepared with cactus tissues of three alternative cactus hosts: opuntia sulphurea, o. quimilo and trichocereus terschekii for 4 consecutive days in lines of two drosophila buzzatii populations and one population of d. koepferae. our results showed that the former laid significantly more eggs on both opuntia cacti than on t. terschekii, whereas d. koepferae preferred t. terschekii. in addition, fecundity schedules differed ... | 2001 | 11831675 |
| fluctuating asymmetry is nongenetically related to mating success in drosophila buzzatii. | to date, there is still no consensus on the real significance of fluctuating asymmetry (fa) in evolutionary biology. some studies have established links between fa and darwinian fitness, and in a number of cases intermediate heritabilities for fa have been reported. however, many claims have been raised against the generality of these findings. i therefore tested if fa of a sexually selected trait (wing length) is indeed related to male mating success in drosophila buzzatii from field and labora ... | 2001 | 11794784 |
| toward a physical map of drosophila buzzatii. use of randomly amplified polymorphic dna polymorphisms and sequence-tagged site landmarks. | we present a physical map based on rapd polymorphic fragments and sequence-tagged sites (stss) for the repleta group species drosophila buzzatii. one hundred forty-four rapd markers have been used as probes for in situ hybridization to the polytene chromosomes, and positive results allowing the precise localization of 108 rapds were obtained. of these, 73 behave as effectively unique markers for physical map construction, and in 9 additional cases the probes gave two hybridization signals, each ... | 2000 | 11102375 |
| expression of the heat-shock protein hsp70 in drosophila buzzatii lines selected for thermal resistance. | the level of hsp70 expression induced by a non-lethal high temperature was examined in lines selected for increased thermal resistance and in corresponding control lines of drosophila buzzatii, in order to test if selection for high temperature resistance leads to an increased level of hsp70 expression. the lines used were selected for up to 64 generations either as adults or through all larval stages. in adult selection lines, hard selection was implemented every second generation after mild he ... | 1999 | 10680297 |
| temporal and spatial variation of inversion polymorphism in two natural populations of drosophila buzzatii. | the inversion polymorphism of the cactophilic fly drosophila buzzatii was studied in two natural populations. we assessed the temporal changes and microspatial population structure. we observed a significant increase in the frequency of arrangement 2j at the expense of 2st in both populations. these gene arrangements appear to affect the life-history of flies differently. environmental heterogeneity explains the karyotype coexistence in nature. the analysis of population structure showed that di ... | 1999 | 10680294 |
| a genetic analysis of the relationship between life-history variation and heat-shock tolerance in drosophila buzzatii. | although exposure to environmental stress is common in most populations, and the physiological effects of stress on individuals are well studied, the evolutionary importance of stress to populations is not well understood. to address multitrait responses to environmental change and potential constraints on character evolution, we analysed, in 100 isofemale lines of drosophila buzzatii, the genetic relationships between resistance to a short heat shock and several life-history traits: survival in ... | 1999 | 10447702 |
| esterase patterns and phylogenetic relationships of species and strains included in the drosophila buzzatii cluster. | ten strains of two species in the drosophila buzzatii cluster (d. serido and d. seriema) were examined as to esterase patterns using polyacrylamide gel electrophoresis. the migration rate of esterases, and their substrate specificity to alpha and beta naphthyl acetates, were analysed. other esterase features such as inhibition behaviour, presence in males and females and location in the head, thorax or abdomen of flies, were also examined. the present data, together with results obtained by othe ... | 1998 | 10384711 |
| inversion polymorphism, longevity, and body size in a natural population of drosophila buzzatii. | in this study we present the results of an analysis of differential longevity associated with drosophila buzzatii second chromosome inversion karyotypes based on the assessment of more than 1000 individuals collected in a natural population. comparisons of inversion frequencies between emerged and bait-collected flies showed not only that inversion arrangements were associated with differential longevity, but also that selection was sex specific. because each individual fly was scored for thorax ... | 1999 | 28565408 |
| 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 |
| sexual selection related to developmental stability in drosophila buzzatii. | relationships among developmental stability, sexual selection, and body size were examined in the cactophilic fly drosophila buzzatii. developmental stability, as measured in terms of fluctuating asymmetry (fa) of wing length, was positively associated to male's copulatory success in a mass-mating experiment with wild-reared flies. previous studies showed that body size is positively correlated with mating success and other fitness components in this species, but no phenotypic correlation betwee ... | 1998 | 9652230 |
| antagonistic pleiotropic effect of second-chromosome inversions on body size and early life-history traits in drosophila buzzatii. | a simple way to think of evolutionary trade-offs is to suppose genetic effects of opposed direction that give rise to antagonistic pleiotropy. maintenance of additive genetic variability for fitness related characters, in association with negative correlations between these characters, may result. in the cactophilic species drosophila buzzatii, there is evidence that second-chromosome polymorphic inversions affect size-related traits. because a trade-off between body size and larval developmenta ... | 1998 | 28568158 |
| correlations among size-related traits are affected by chromosome inversions in an adaptive polymorphism in drosophila buzzatii. | genetic variation in correlations among size-related traits of head, thorax and wings was examined in drosophila buzzatii, by comparing the correlation pattern of the phenotypic correlation matrix (cp-rp) between inversion karyotypes of the second chromosome. cp-rp differed between some karyotypes in a natural population. cp-rp in homokaryotypic classes of wild-reared flies, but not in heterokaryotypes, differed from the whole population represented by laboratory-reared flies. similarity in cp-r ... | 1997 | 9418266 |
| estimating heritability in a threshold trait: heat-shock tolerance in drosophila buzzatii. | stress tolerance is often measured as a threshold trait, the proportion of a group that survives a defined stress regime. requirements of large offspring numbers coupled with fitness variation in the surviving cohort limit the use of some standard genetic analyses for estimating heritability. therefore, we present an isofemale line analysis, which is a modified full-sib design, to estimate heritability of tolerance to heat shock in pretreated drosophila buzzatii adults. highly significant levels ... | 1997 | 9316252 |
| inversion length and breakpoint distribution in the drosophila buzzatii species complex: is inversion length a selected trait? | length and position of breakpoints are characteristics of inversions that can be precisely determined on the polytene chromosomes of drosophila species, and they provide crucial information about the processes that govern the origin and evolution of inversions. eighty-six paracentric inversions described in the drosophila buzzatii species complex and 18 inversions induced by introgressive hybridization in d. buzzatii were analyzed. in contrast to previous studies, inversion length and breakpoint ... | 1997 | 28565492 |
| genetic and phenotypic correlations among size-related traits, and heritability variation between body parts in drosophila buzzatii. | recent studies have shown that body size is a heritable trait phenotypically correlated with several fitness components in wild populations of the cactophilic fly drosophila buzzatii. to obtain further information on size-related variation, heritabilities as well as genetic and phenotypic correlations among size-related traits of several body parts (head, thorax and wings) were estimated. the study was carried out on an argentinean natural population in which size-related selection was previousl ... | 1997 | 9465404 |
| correlations among size-related traits affected by chromosome inversions in drosophila buzzatii: the comparison within and across environments. | genetic variation in correlations among size-related traits of head, thorax, and wings was examined in drosophila buzzatii, by comparing the pattern of the phenotypic correlation matrix (rp) between inversion karyotypes of the second chromosome. no similarity in rp was observed between some karyotypes in a natural population. the pattern of rp in wild-reared heterokaryotypes, but not in homokaryotypes, was similar to the whole population represented by laboratory-reared flies. while phenotypic c ... | 1997 | 9350137 |
| high-temperature stress and the evolution of thermal resistance in drosophila. | the evolution of thermal resistance and acclimation is reviewed at the population level using populations and isofemale lines of drosophila buzzatii and d. melanogaster originating from different climatic regions. in general, ample genetic variation for thermal resistance was found within and among populations. a rough correlation between the climate of origin and thermal resistance was apparent. acclimation at a non-lethal temperature led to a significant increase in survival after heat shock, ... | 1997 | 9342849 |
| selection for heat-shock resistance in larval and in adult drosophila buzzatii: comparing direct and indirect responses. | direct and correlated responses in selection for heat-shock resistance in adult and in larval drosophila buzzatii were studied. two lines were artificially selected for higher survival to heat stress as adults, and two other lines were reared under a fluctuating thermal environment as larvae, 35°c for 6 h and 25°c for 18 h, to "naturally" select for higher resistance as larvae. the latter two lines were duplicated after nine generations to yield additional lines to be "naturally" selected as lar ... | 1996 | 28565653 |
| apparent directional selection of body size in drosophila buzzatii: larval crowding and male mating success. | | 1996 | 28565651 |
| a three-locus system of interspecific incompatibility underlies male inviability in hybrids between drosophila buzzatii and d. koepferae. | in hybrids between the sibling species d. buzzatii and d. koepferae, both sexes are more or less equally viable in the f1. however, backcross males to d. buzzatii are frequently inviable, apparently because of interspecific genetic incompatibilities that are cryptic in the f1. we have performed a genetic dissection of the effects of the x chromosome from d. koepferae. we found only two cytological regions, termed hmi-1 and hmi-2, altogether representing 9% of the whole chromosome, which when int ... | 1996 | 8765678 |
| genetic architecture of autosome-mediated hybrid male sterility in drosophila. | several estimators have been developed for assessing the number of sterility factors in a chromosome based on the sizes of fertile and sterile introgressed fragments. assuming that two factors are required for producing sterility, simulations show that one of these, twice the inverse of the relative size of the largest fertile fragment, provides good average approximations when as few as five fertile fragments are analyzed. the estimators have been used for deducing the number of factors from pr ... | 1996 | 8846896 |
| acclimation and selection for increased resistance to thermal stress in drosophila buzzatii. | direct selection for increased resistance to a heat shock (41.9 degrees for 90 min) was carried out using two replicate lines of drosophila buzzatii that were derived from a large base population. selected individuals were first acclimated to high temperature before selection, while control individuals were acclimated but not selected, and selection was performed every second generation. resistance to heat shock with acclimation increased in selected lines. without acclimation, a correlated smal ... | 1996 | 8852846 |
| phylogenetic utility of the mitochondrial cytochrome oxidase gene: molecular evolution of the drosophila buzzatii species complex. | phylogenetic relationships among eight species of the drosophila buzzatii species complex (d. mulleri subgroup; d. repleta species group) and d. hamatofila were determined by sequencing the mitochondrial cytochrome oxidase subunit i, ii, and iii genes. the species examined included members of the martensis cluster (d. martensis, d. starmeri, d. venezolana), the buzzatii cluster (d. buzzatii, d. serido, d. borborema), and the stalkeri cluster (d. stalkeri, d. richardsoni). the molecular phylogeny ... | 1995 | 8587120 |
| heritability and selection on body size in a natural population of drosophila buzzatii. | an attempt was made to assess whether the phenotypic differences in body size (as measured by wing length) between wild-caught mating and single drosophila buzzatii males could be attributed to genetic differences between the samples. mating males were found to be larger and less variable than a random sample of the population. the progeny of the mating males (produced by crossing to a random female from a stock derived from the same population) were on average larger than those of the single ma ... | 1995 | 8536966 |
| the evolutionary history of drosophila buzzatii. xxxii. linkage disequilibrium between allozymes and chromosome inversions in two colonizing populations. | chromosome polymorphism in drosophila buzzatii is under selection but the genes responsible for the effect of the inversions of fitness are unknown. on the other hand, there is evidence for selection on several allozyme loci but the presence of paracentric inversions on the second chromosome, where most of the polymorphic loci are located, complicates the interpretation. studies of the associations between allozymes and inversions are thus necessary to help understand the effect of selection at ... | 1995 | 7706110 |
| esterase patterns of species in the drosophila buzzatii cluster. | a comparative analysis was made of the esterase isoenzyme patterns of eight iso-female lines, four of drosophila serido (b31 d1, a55, b59, q1, b50q3), two of d. koepferae (b20d2 and b25d7), one of d. seriema (a95) and one of d. buzzatii (buz). in all, 43 bands in the spectrum of esterase isoenzymes were detected by electrophoresis in polyacrylamide gels. they showed variations in specific reactions with alpha and beta-naphthyl acetate, number of patterns yielded in their intra-isofemale line com ... | 1995 | 8681607 |
| an adaptive chromosomal polymorphism affecting size-related traits, and longevity selection in a natural population of drosophila buzzatii. | size-related phenotypic variation among second-chromosome karyotypes in drosophila buzzatii was examined in an argentinian natural population. for all measured traits (thorax and wing length; wing, head and face width), this inversion polymorphism exhibited a significant and (additive) linear contribution to the phenotypic variance in newly emerged wild flies. the results suggest that only overall body size, and not body shape, is affected, as no karyotypic variation was found for any trait when ... | 1995 | 8522167 |
| high transposition rates of osvaldo, a new drosophila buzzatii retrotransposon. | transposition of a new drosophila retrotransposon was investigated. total genomic southern analysis and polytene in situ hybridizations in d. buzzatii strains and other related species using a 6 kb d. buzzatii clone (cdb314) showed a dispersed, repetitive dna pattern, suggesting that this clone contains a transposable element (te). we have sequenced the cdb314 clone and demonstrated that it contains all the conserved protein sequences and motifs typical of retrovirus-related sequences. although ... | 1994 | 7545973 |
| fatty acid elongation in the biosynthesis of (z)-10-heptadecen-2-one and 2-tridecanone in ejaculatory bulb microsomes of drosophila buzzatii. | a fatty acid chain elongation process is involved in incorporation of saturated and unsaturated fatty acyl-coa esters into 2-tridecanone and (z)-10-heptadecen-2-one by drosophila buzzatii. the microsomal fraction from mature male ejaculatory bulbs is chain-length specific and requires malonyl-coa (or acetyl-coa, if acetyl-coa carboxylase were present) for the chain elongation step to 2-ketones. decarboxylation of the proposed intermediate beta-ketoacid results in 2-ketone biosynthesis. incubatio ... | 1994 | 7981731 |
| mating pattern and fitness-component analysis associated with inversion polymorphism in a natural population of drosophila buzzatii. | direct studies of mating success or mating pattern associated with mendelian factors rarely have been carried out in nature. from the samples taken for the standard analyses of selection components, it is not usually possible to obtain the mating table, and only directional selection for male mating success can be detected. both processes, mating pattern and differential mating probability, together with other fitness components, have been investigated for the inversion polymorphism of a natural ... | 1994 | 28568257 |
| f statistics in drosophila buzzatii: selection, population size and inbreeding. | drosophila buzzatii is confined to reproducing in a well defined patchy environment consisting of rotting cactus cladodes which are ephemeral, permitting at most three generations. flies emerging from such rots were used to estimate the additive genetic variance within rots and the genetic variance between rots for body size and also were electrophoresed to determine their genotypes at six polymorphic loci. f statistics were estimated from body size and allozyme data. the fst derived from body s ... | 1993 | 8514144 |
| genetics and linkage mapping of drosophila buzzatii. | of 51 visible mutants isolated from natural or laboratory populations of drosophila buzzatii, or x-ray induced, 42 have been assigned to chromosomes, and linkage maps have been constructed. about half of the autosomal mutants map to chromosome 2, with only two on chromosome 3 and none on chromosome 4. for the whole repleta group, chromosome 2 also exhibits much greater inversion variability than other chromosomes, which suggests variation among chromosomes in apparent mutability. the chromosomes ... | 2010 | 8228173 |
| lack of mitochondrial dna variation in australian drosophila buzzatii. | | 1993 | 8487641 |
| quantitative genetic analysis of the body size and shape of drosophila buzzatii. | body size in drosophila is known to be closely related to a number of traits with important life history consequences, such as fecundity, dispersal ability and mating success. we examine the quantitative genetic basis of body size in three populations of the cactophilic species drosophila buzzatii, which inhabit climatically different areas of australia. flies were reared individually to eliminate any common environmental component in a full-sib design with families split between two temperature ... | 1993 | 24195935 |
| the evolutionary history of drosophila buzzatii. xxiii. high content of nonsatellite repetitive dna in d. buzzatii and in its sibling d. koepferae. | the frequency and types of repetitive nonsatellite dna of two sibling species of the repleta group of drosophila, d. buzzatii, and d. koepferae have been determined. for each species, the analysis is based on a sample of more than 100 clones (400 kb) obtained from genomic dna. a theoretical model has been developed to correct for the presence of a mixture of repetitive and unique dna in these clones. after correction, a high content of repetitive dna has been demonstrated for both species (d. bu ... | 1992 | 1473728 |
| the evolutionary history of drosophila buzzatii. xxiv. second chromosome inversions have different average effects on thorax length. | we demonstrate a genetic correlation between rearrangements of the second chromosome of d. buzzatii and thorax length, as a measure of body size. the results indicate that 2j and 2jz3 arrangements are correlated with large size, whereas 2st arrangement is correlated with small size. some inversions (2st and 2jz3) show dominant effects and others (2j/jz3) exhibit overdominance. these results show that at least 25 per cent of body size variation may be accounted for by the studied karyotypes. the ... | 1992 | 1612928 |
| the evolutionary history of drosophila buzzatii. xxv. random mating in nature. | using allozymes as the genetic probe, data are presented which show that wild drosophila buzzatii females and males engaged in copulation mate at random. hence, putative inbreeding due to local mating of genetically related flies emerging from the patchy distributed substrates, was not detected. we conclude that individuals raised from a niche disperse and mate at random with other members of the population, so only one round of drift due to the colonization of suitable and ephemeral breeding si ... | 1992 | 1563969 |
| the evolutionary history of drosophila buzzatii. xxi. cumulative action of multiple sterility factors on spermatogenesis in hybrids of d. buzzatii and d. koepferae. | the genetic basis of sterility in male hybrids of drosophila buzzatii and d. koepferae has been investigated by assessment of the effects on spermatogenesis of substituting separate chromosome segments of the recipient species with the homologous material from the donor species, either in heterozygous (autosomes) or hemizygous (x chromosome) condition, after successive backcrossing of hybrid females to either parental species. introgressed segments were identified by the characteristic asynapsis ... | 1991 | 1917552 |
| 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 |
| ecological aspects of the heritability of body size in drosophila buzzatii. | the heritability of thorax length in the cactophilic drosophila buzzatii was determined for flies from each of 10 rotting cactus cladodes. for each rot, emerging flies were used as parents of progeny reared in the laboratory. the methods used were full sib analysis with the parents mated assortatively and also offspring-parent regression. from this, heritabilities were measured for the laboratory environment and for the natural environment of the rotting cladode. for the laboratory environment, ... | 1989 | 2612896 |
| the evolutionary history of drosophila buzzatii. xii. the genetic basis of sterility in hybrids between d. buzzatii and its sibling d. serido from argentina. | the genetic basis of hybrid sterility has been investigated in backcross segmental hybrids between two sibling species, drosophila buzzatii and d. serido. asynapsis of homologous bands in hybrid polytene chromosomes has been used to identify the d. serido chromosome segments introgressed into the d. buzzatti genome. all the investigated chromosomes contain male sterility factors. for autosomes, sterility is produced when an introgressed d. serido chromosome segment, or combination of segments, r ... | 1986 | 17246354 |
| frequency and temperature dependent selection at the alcohol dehydrogenase-1 locus of drosophila buzzatii. | genotype frequencies at the alcohol dehydrogenase-1 (adh-1) locus of d. buzzatii were analysed for deviations from hardy-weinberg equilibria in the progeny of laboratory populations established at five initial adh-1b allele frequencies and kept at either 18 degrees c, 25 degrees c or 30 degrees c. at 25 degrees c, no observed genotype frequencies were significantly different from hardy-weinberg expectations. observed frequencies of heterozygotes were generally less than expected for populations ... | 1986 | 2943702 |
| the evolutionary history of drosophila buzzatii. viii. evidence for endocyclic selection acting on the inversion polymorphism in a natural population. | the pattern of selection acting in nature on the chromosomal polymorphism of the cactophilic species drosophila buzzatii was investigated by comparing inversion and karyotypic frequencies through four different life-cycle stages: adult males, eggs, third-instar larvae, and immature adults. all population samples were obtained in june 1981 at an old opuntia ficus-indica plantation near carboneras, spain. the analysis rests on several assumptions which are explicitly set forth and discussed. the r ... | 1986 | 28556170 |
| allozyme genotypes of drosophila buzzatii: feeding and oviposition preferences for microbial species, and habitat selection. | mature, mated female d. buzzatii were given a choice of nine microbial communities actively growing on cactus homogenate in laboratory population cages, and tests were made to determine if flies of different genotypes (for seven allozyme loci) chose different microorganism species for either feeding or oviposition. variation in feeding preferences was determined from assays of electrophoretic genotypes and the ingested microorganism species of individual flies. oviposition preference variation w ... | 1986 | 3778358 |
| the evolutionary history of drosophila buzzatii. ix. high frequencies of new chromosome rearrangements induced by introgressive hybridization. | introgression of a chromosome segment from drosophila serido into the genome of its sibling d. buzzatii brought about the release of mutator potential in the hybrids. mutator activity was determined by examining the frequency of new chromosomal rearrangements, that appeared only in the progeny of hybrid individuals. mutation frequency was 30 times greater in the progeny of hybrid males than in that of hybrid females. there was a remarkable influence of the d. buzzatii genetic background on the f ... | 1985 | 3987443 |
| evolutionary history of drosophila buzzatii. ii. how much has chromosomal polymorphism changed in colonization? | | 1982 | 28568228 |
| the evolutionary history of drosophila buzzatii. iii. cytogenetic relationships between two sibling species of the buzzatii cluster. | drosophila buzzatii has been found sympatric in argentina with a closely-related sibling species, d. serido. the biogeographical, reproductive and chromosomal data allow us to combine these species into an evolutionary unit, the buzzatii cluster. salivary gland chromosomes also have been used to determine their phylogenetic relationships with other closely related species, showing that the buzzatii cluster species share two inversions-2d(2) and 2s(6)-with the species of the martensis cluster. bo ... | 1982 | 17246089 |
| evolutionary history of drosophila buzzatii. i. natural chromosomal polymorphism in colonized populations of the old world. | | 1981 | 28563456 |
| allozyme genotype--environment relationships in natural populations of drosophila buzzatii. | allozyme frequency data from natural populations of drosophila buzzatii were analyzed for genotype--environment relationships. allele frequency and heterozygosity at six loci polymorphic throughout eastern australia and a number of environmental factors (both means and variabilities) were examined by a variety of multivariate techniques. significant genotype--environment associations were found for five of the six loci, and after correcting for geographic location significant associations remain ... | 1979 | 454353 |
| isozyme variation in natural populations of drosophila buzzatii. | | 1976 | 28563041 |