共查询到20条相似文献,搜索用时 15 毫秒
1.
Zakharenko LP Zakharov IK Romanova OA Voloshina MA Gracheva EM Kochieva EZ Golubovskiĭ MD Georgiev PG 《Genetika》2000,36(6):740-748
A mutation outburst of the yellow gene occurred in a Drosophila melanogaster population from the town of Uman' from 1982 to 1991 and was associated with the instability of several alleles. Molecular genetic analysis revealed a deletion variant of the hobo transposable element in the same site of the regulatory region of yellow in the mutant alleles and their derivatives. The outburst of the yellow-2 mutations was attributed to the spreading of the X chromosome, which contained an inversion of the yellow regulatory region, through the population. Reinversion resulted in the wild-type phenotype. Crossing lines carrying the inversion with laboratory line C(1)DX, ywf induced instability of the yellow alleles, which was associated with duplication or multiplication of a fragment of the yellow gene. Most derivative lines eventually became stable. The loss of instability was not associated with phenotypic changes; molecular genetic changes included a loss of the duplicated sequences or a deletion of the inverted regulatory region of the yellow gene. 相似文献
2.
L. P. Zakharenko I. K. Zakharov M. A. Voloshina O. M. Romanova A. A. Alekseenko P. G. Georgiev 《Russian Journal of Genetics》2004,40(3):239-243
Mobile genetic elements are responsible for most spontaneous mutations in Drosophila melanogaster. The discovered in the 1980s phenomenon of frequent change of the wild-type yellow phenotype for a mutant one, and vice-versa, in strains of D. melanogaster isolated from the Uman' natural population can be, according to our data, explained by repeated inversions and reinversions of the gene regulatory region located between the two copies of the hobo transposon. However, most molecular genetic events accompanying the process can occur without the phenotype change. After several generations, the strains, remaining phenotypically unchanged, can possess different molecular genetic properties with respect to yellow. Using genetically homogenous or isogenic strains for the genetic analysis or for production of the new plant cultivars or animal breeds, geneticists and breeders often face the problem of stability of the strains. In the present study, the mechanism underlying the generation of instability at the yellowlocus of D. melanogaster determined by the hobo-induced genome instability is described. 相似文献
3.
Olfactory sensitivity and locomotor activity was assayed in Drosophila melanogaster strains carrying a mutation of the flamenco gene, which controls transposition of the mobile genetic element 4 (MGE4) retrotransposon the gypsy mobile element. A change in olfactory sensitivity was detected. The reaction to the odor of acetic acid was inverted in flies of the mutator strain (MS), which carried the flam mutation and active MGE4 copies and were characterized by genetic instability. Flies of the genetically unstable strains displayed a lower locomotor activity. The behavioral changes in MS flies can be explained by the pleiotropic effect of the flam mutation or by insertion mutations which arise in behavior genes as a result of genome destabilization by MGE4. 相似文献
4.
A. Pélisson L. Teysset F. Chalvet A. Kim N. Prud'homme C. Terzian A. Bucheton 《Genetica》1997,100(1-3):29-37
The gypsy element of Drosophila melanogaster is the first retrovirus identified so far in invertebrates. According to phylogenetic
data, gypsy belongs to the same group as the Ty3 class of LTR-retrotransposons, which suggests that retroviruses evolved from
this kind of retroelements before the radiation of vertebrates. There are other invertebrate retroelements that are also likely
to be endogenous retroviruses because they share with gypsy some structural and functional retroviral-like characteristics.
Gypsy is controlled by a Drosophila gene called flamenco, the restrictive alleles of which maintain the retrovirus in a repressed
state. In permissive strains, functional gypsy elements transpose at high frequency and produce infective particles. Defective
gypsy proviruses located in pericentromeric heterochromatin of all strains seem to be very old components of the genome of
Drosophila melanogaster, which indicates that gypsy invaded this species, or an ancestor, a long time ago. At that time, Drosophila
melanogaster presumably contained permissive alleles of the flamenco gene. One can imagine that the species survived to the
increase of genetic load caused by the retroviral invasion because restrictive alleles of flamenco were selected. The characterization
of a retrovirus in Drosophila, one of the most advanced model organisms for molecular genetics, provides us with an exceptional
clue to study how a species can resist a retroviral invasion.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
5.
According to FISH data the presence of multiple hobo element copies in the unstable yellow and Notch loci in y(2-717) and Uc-1 Drosophila melanogaster stocks, respectively, was found. Locus-specific instability in these strains is caused by hobo multiplication in the respective loci and its subsequent recombination with neighboring hobo copies rather than its insertion-excision. 相似文献
6.
Mutations Lobe induced by the microinjections of RSV cDNA into Drosophila melanogaster early embryos are characterized by permanent genetic instability; the level of this instability is being changed in time. Based on the results of genetic analyses of Lobe mutations and molecular analysis of white and ADH mutations induced at high frequency in this system of gene instability, we supposed that unstable mutations which arose under the influence of retroviral cDNA are of the insertional nature. 相似文献
7.
Drapeau MD 《Biochemical and biophysical research communications》2003,311(1):1-3
In Drosophila melanogaster, the protein product of the yellow gene is necessary for normal pigmentation and male sexual behavior. Although one of the best characterized loci from a genetic standpoint, the function of the Yellow protein in the development of either phenotype is unknown. Here I propose that Yellow acts as a growth factor- or hormone-like molecule in the development of pigmentation and sexual behavior, and discuss the consistency of this theory with experimental observations in flies and humans. 相似文献
8.
Recent investigations showed that genetic instability accounts for many radiobiological effects. However, mechanisms underlying this phenomenon are still poorly understood. Assuming that mobile genetic elements may be involved in the induction of genetic instability, we studied parameters that characterize the activity of these elements in Drosophila melanogaster: hybrid dysgenesis and the level of recessive lethal mutations. In our experiments, we used D. melanogaster strains that differed in the type of hybrid dysgenesis (P-M and H-E). It was demonstrated that chronic exposure to radiation leads to substantial changes in the genetic structure of a population and an enhanced level of dysgenic sterility. Our results indicate that genetic instability and adaptation to the effect of chronic gamma-radiation are associated with the radiation-induced mobilization of mobile genetic elements. 相似文献
9.
The molecular genetics of the Notch locus in Drosophila melanogaster 总被引:13,自引:0,他引:13
B G Grimwade M A Muskavitch W J Welshons B Yedvobnick S Artavanis-Tsakonas 《Developmental biology》1985,107(2):503-519
10.
11.
S D Nabirochkin S G Georgieva T V Begetova P G Georgiev I V Makarova T I Gerasimova K G Gazarian 《Genetika》1991,27(4):609-616
We have demonstrated that mutations induced in Drosophila melanogaster by the microinjections of adenovirus Sa7 DNA in early embryos are of insertional nature. The role of insertional elements is played by the Drosophila transposons, but not by the virus DNA. The ability of oncoviral DNA to induce transpositions of mobile elements in recipient genome is the molecular basis of this system of genetic instability. 相似文献
12.
13.
Absolute constraints are limitations on genetic variation that preclude evolutionary change in some aspect of the phenotype. Absolute constraints may reflect complete absence of variation, lack of genetic variation that extends the range of phenotypes beyond some limit, or lack of additive genetic variation. This last type of absolute constraint is bidirectional, because the mean cannot evolve to be larger or smaller. Most traits do possess genetic variation, so bidirectional absolute constraints are most likely to be detected in a multivariate context, where they would reflect combinations of traits, or dimensions in phenotype space that cannot evolve. A bidirectional absolute constraint will cause the additive genetic covariance matrix (G) to have a rank less than the number of traits studied. In this study, we estimate the rank of the G-matrix for 20 aspects of wing shape in Drosophila melanogaster. Our best estimates of matrix rank are 20 in both sexes. Lower 95% confidence intervals of rank are 17 for females and 18 for males. We therefore find little evidence of bidirectional absolute constraints. We discuss the importance of this result for resolving the relative roles of selection and drift processes versus constraints in the evolution of wing shape in Drosophila. 相似文献
14.
Adaptive protein evolution of X-linked and autosomal genes in Drosophila: implications for faster-X hypotheses 总被引:1,自引:0,他引:1
Connallon T 《Molecular biology and evolution》2007,24(11):2566-2572
Patterns of sex chromosome and autosome evolution can be used to elucidate the underlying genetic basis of adaptative change. Evolutionary theory predicts that X-linked genes will adapt more rapidly than autosomes if adaptation is limited by the availability of beneficial mutations and if such mutations are recessive. In Drosophila, rates of molecular divergence between species appear to be equivalent between autosomes and the X chromosome. However, molecular divergence contrasts are difficult to interpret because they reflect a composite of adaptive and nonadaptive substitutions between species. Predictions based on faster-X theory also assume that selection is equally effective on the X and autosomes; this might not be true because the effective population sizes of X-linked and autosomal genes systematically differ. Here, population genetic and divergence data from Drosophila melanogaster, Drosophila simulans, and Drosophila yakuba are used to estimate the proportion of adaptive amino acid substitutions occurring in the D. melanogaster lineage. After gene composition and effective population size differences between chromosomes are controlled, X-linked and autosomal genes are shown to have equivalent rates of adaptive divergence with approximately 30% of amino acid substitutions driven by positive selection. The results suggest that adaptation is either unconstrained by a lack of beneficial genetic variation or that beneficial mutations are not recessive and are thus highly visible to natural selection whether on sex chromosomes or on autosomes. 相似文献
15.
The results of three long-term breeding and genetic experiments with Drosophila melanogaster performed at different times are summarized. Selections for different fitness components led to similar results. The data on the concentration of viability mutations in the inbred strains LA, LA+, and LA- after 400 generations of selection and the strain ULA during its breeding are presented for the first time. The results of studying the genetic heterogeneity and spontaneous mutational process in Drosophila inbred strains comply with the idea of M.E. Lobashev that "a change in the direction of selection or acceleration of its rate is always accompanied by a concurrent increase in mutational variation". 相似文献
16.
Evidence for Regulatory Variants of the Dopa Decarboxylase and Alpha-Methyldopa Hypersensitive Loci in Drosophila 总被引:4,自引:2,他引:2
下载免费PDF全文
![点击此处可从《Genetics》网站下载免费的PDF全文](/ch/ext_images/free.gif)
We have analyzed two variants of Drosophila melanogaster (RS and RE) which lead to the dual phenotype of elevated DDC activity and increased resistance to dietary alpha-methyldopa relative to Oregon-R controls. Both phenotypes show tight genetic linkage to the dopa decarboxylase, Ddc, and l(2)amd genes (i.e., less than 0.05 cM distant). We find that low (Oregon-R), medium (RS) and high (RE and Canton-S) levels of DDC activity seen at both pupariation and eclosion in these strains are completely accounted for by differences in accumulation of DDC protein as measured by immunoprecipitation. Genetic reconstruction experiments in which Ddc+ and amd+ gene doses are varied show that increasing DDC activity does not lead to a measurable increase in resistance to dietary alpha-methyldopa. This suggests that the increased resistance to dietary alpha-methyldopa is not the result of increased DDC activity but, rather, results from increased l(2)amd+ activity. Both cytogenetic and molecular analyses indicate that these overproduction variants are not the result of small duplications of the Ddc and amd genes, nor are they associated with small (greater than or equal to 100 bp) insertions or deletions. Measurements of DDC activity in wild-type strains of Drosophila reveal a unimodal distribution of activity levels with the Canton-S and RE strains at the high end of the scale, the Oregon-R control at the low end and RS near the modal value. We conclude that accumulated changes in a genetic element (or elements) in close proximity to the Ddc+ and amd+ genes lead to the coordinated changes in the expression of the Ddc and amd genes in these strains. 相似文献
17.
18.
19.
20.
Jackson SM Whitworth AJ Greene JC Libby RT Baccam SL Pallanck LJ La Spada AR 《Gene》2005,347(1):35-41
CAG and CTG repeat expansions are the cause of at least a dozen inherited neurological disorders. In these so-called "dynamic mutation" diseases, the expanded repeats display dramatic genetic instability, changing in size when transmitted through the germline and within somatic tissues. As the molecular basis of the repeat instability process remains poorly understood, modeling of repeat instability in model organisms has provided some insights into potentially involved factors, implicating especially replication and repair pathways. Studies in mice have also shown that the genomic context of the repeat sequence is required for CAG/CTG repeat instability in the case of spinocerebellar ataxia type 7 (SCA7), one of the most unstable of all CAG/CTG repeat disease loci. While most studies of repeat instability have taken a candidate gene approach, unbiased screens for factors involved in trinucleotide repeat instability have been lacking. We therefore attempted to use Drosophila melanogaster to model expanded CAG repeat instability by creating transgenic flies carrying trinucleotide repeat expansions, deriving flies with SCA7 CAG90 repeats in cDNA and genomic context. We found that SCA7 CAG90 repeats are stable in Drosophila, regardless of context. To screen for genes whose reduced function might destabilize expanded CAG repeat tracts in Drosophila, we crossed the SCA7 CAG90 repeat flies with various deficiency stocks, including lines lacking genes encoding the orthologues of flap endonuclease-1, PCNA, and MutS. In all cases, perfect repeat stability was preserved, suggesting that Drosophila may not be a suitable system for determining the molecular basis of SCA7 CAG repeat instability. 相似文献