scholarly journals Differences in P element population dynamics between the sibling species Drosophila melanogaster and Drosophila simulans

1994 ◽  
Vol 63 (1) ◽  
pp. 27-38 ◽  
Author(s):  
Kiyoshi Kimura ◽  
Margaret G. Kidwell
Keyword(s):  
Natural Populations ◽  
Host Factors ◽  
P Element ◽  
Enzyme Analysis ◽  
Restriction Enzyme Analysis ◽  
Species Variation ◽  
Transposition Frequency ◽  
Copy Numbers ◽  
Activity Difference ◽  
Mixed Populations

SummaryPatterns of P element establishment and evolution were compared in populations of D. melanogaster and D. simulans. For each species, mixed populations were initiated with M strain flies lacking P elements together with P strain flies having similar P element copy numbers and phenotypes. The mixed populations were subsequently maintained under similar environmental conditions. On the basis of gonadal sterility assays, P elements tended to be significantly more active in D. melanogaster than in D. simulans populations. This activity difference between the two species was positively associated with P element copy number, determined by restriction enzyme analysis, and transposition frequency, as determined by a transposition assay. Host factors are the most likely explanation for the observed species variation. Difficulty of establishment may be a factor determining the absence of P elements in natural populations of D. simulans.

scholarly journals FREQUENT IMPRECISE EXCISION AMONG REVERSIONS OF A P ELEMENT-CAUSED LETHAL MUTATION IN DROSOPHILA

Genetics ◽  
1984 ◽  
Vol 107 (2) ◽  
pp. 279-294
Author(s):  
Robert A Voelker ◽  
Arno L Greenleaf ◽  
Henrik Gyurkovics ◽  
G Bruce Wisely ◽  
Shu-Mei Huang ◽  
...  
Keyword(s):  
Rna Polymerase Ii ◽  
Restriction Enzyme ◽  
Excision Repair ◽  
Lethal Mutation ◽  
P Element ◽  
Enzyme Analysis ◽  
Restriction Enzyme Analysis ◽  
Imprecise Excision ◽  
Meiotic Mutations ◽  
By Products

ABSTRACT RpII215D  50 (= D50) is a lethal mutation caused by the insertion of a 1.3-kb P element 5′ to sequences encoding the largest (215 kilodaltons) subunit of Drosophila RNA polymerase II. In dysgenic males D50 reverted to nonlethality at frequencies ranging from 2.6 to 6.5%. These reversions resulted from loss of P element sequences. Genetic tests of function and restriction enzyme analysis of revertant DNAs revealed that 35% or more of the reversion events were imprecise excisions. Two meiotic mutations that perturb excision repair and postreplication repair (mei-9a and mei-41D  5, respectively) had no influence on reversion frequency but may have increased the proportion of imprecise excisions. We suggest that these excisions are by-products of, rather than intermediates in, the transposition process.

Variation in natural populations of Drosophila as revealed by four-cutter analysis

Genome ◽  
1989 ◽  
Vol 31 (2) ◽  
pp. 784-787 ◽  
Author(s):  
Montserrat Aguadé
Keyword(s):  
Restriction Site ◽  
Natural Populations ◽  
Restriction Enzymes ◽  
Dna Polymorphisms ◽  
Enzyme Analysis ◽  
Restriction Enzyme Analysis ◽  
Molecular Variation ◽  
Deletion Polymorphism ◽  
Isolated Populations ◽  
Chromosome Arrangements

Four-cutter restriction enzyme analysis, a recently developed electroblotting technique, enables the survey of restriction site and insertion–deletion polymorphism in natural populations at a fine level of resolution. Using this technique, the distribution of polymorphism among geographically isolated populations of Drosophila melanogaster and in different structural–functional domains of the genome has been studied. A summary of these results is presented and discussed. Recent investigations of molecular variation within and between different chromosome arrangements in Drosophila are presented. Levels of variation in different regions of the X chromosome of D. melanogaster are also discussed.Key words: populations, DNA polymorphisms, Drosophila, restriction enzymes.

scholarly journals Molecular evolution of Drosophila metallothionein genes.

Genetics ◽  
1990 ◽  
Vol 126 (4) ◽  
pp. 921-932 ◽  
Author(s):  
B W Lange ◽  
C H Langley ◽  
W Stephan
Keyword(s):  
Natural Populations ◽  
Sequence Divergence ◽  
Copper Tolerance ◽  
Enzyme Analysis ◽  
Restriction Enzyme Analysis ◽  
Nucleotide Polymorphism ◽  
Heavy Metal Detoxification ◽  
Recent Origin ◽  
Selection For ◽  
Tandem Duplications

Abstract The metallothionein genes of Drosophila melanogaster, Mtn and Mto, may play an important role in heavy metal detoxification. Several different tandem duplications of Mtn have been shown to increase cadmium and copper tolerance, as well as Mtn expression. In order to investigate the possibility of increased selection for duplications of these genes in natural populations exposed to high levels of heavy metals, we compared the frequencies of such duplications among flies collected from metal-contaminated and non-contaminated orchards in Pennsylvania, Tennessee and Georgia. Restriction enzyme analysis was used to screen 1666 wild third chromosomes for Mtn duplications and a subset (327) of these lines for Mto duplications. The frequency of pooled Mtn duplications found ranged from 0% to 20%, and was not significantly higher at the contaminated sites. No Mto duplications were identified. Estimates of sequence diversity at the Mtn locus among a subsample (92) of the duplication survey were obtained using four-cutter analysis. This analysis revealed a low level of polymorphism, consistent with both selection at the Mtn locus, and a fairly recent origin for the duplications. To further examine this hypothesis, we sequenced an Mtn allele of Drosophila simulans and measured the amount of nucleotide sequence divergence between D. simulans and its sibling species D. melanogaster. The levels of silent nucleotide polymorphism and divergence in the Mtn region were compared with those in the Adh region, using the neutrality test of R.R. Hudson, M. Kreitman and M. Aguadé.

Transposable elements and fitness in Drosophila melanogaster

Genome ◽  
1989 ◽  
Vol 31 (1) ◽  
pp. 284-295 ◽  
Author(s):  
Trudy F. C. Mackay
Keyword(s):  
Drosophila Melanogaster ◽  
Transposable Elements ◽  
Insertional Mutagenesis ◽  
Natural Populations ◽  
P Element ◽  
Induced Mutations ◽  
P Elements ◽  
Copy Numbers ◽  
Genomic Locations

Transposable elements constitute a significant fraction of the Drosophila melanogaster genome. The five families of moderately repeated transposable elements identified to date occupy dispersed and variable genomic locations, but have relatively constant copy numbers per individual. What effect to these elements have on the fitness of the individuals harboring them? Experimental evidence relating to this question is reviewed. The relevant data fall into two broad categories. The first involves the determination of the distribution of transposable elements in natural populations, by restriction mapping or in situ hybridization, and the comparison of the observed distribution with different theoretical expectations. The second approach is to study directly the effects of new transposable element-induced mutations on fitness. The P family of transposable elements is a particularly efficient mutagen, and the results of experiments in which initially P-free chromosomes are contaminated with P elements are discussed with regard to P-induced fitness mutations.Key words: transposable elements, Drosophila melanogaster, insertional mutagenesis, fitness, P element mutagenesis, hybrid dysgenesis.

scholarly journals The Regulatory Properties of Autonomous Subtelomeric P Elements Are Sensitive to a Suppressor of variegation in Drosophila melanogaster

Genetics ◽  
1996 ◽  
Vol 143 (4) ◽  
pp. 1663-1674 ◽  
Author(s):  
Stéphane Ronsseray ◽  
Monique Lehmann ◽  
Danielle Nouaud ◽  
Dominique Anxolabéhère
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Recombination ◽  
Natural Populations ◽  
P Element ◽  
Single Element ◽  
Heterochromatin Protein 1 ◽  
X Chromosomes ◽  
P Elements ◽  
Associated Sequences ◽  
Regulatory Properties

Abstract Genetic recombination was used in Drosophila melanogaster to isolate P elements, inserted at the telomeres of X chromosomes (cytological site 1A) from natural populations, in a genetic background devoid of other P elements. We show that complete maternally inherited P repression in the germline (P cytotype) can be elicited by only two autonomous P elements at 1A and that a single element at this site has partial regulatory properties. The analysis of the surrounding chromosomal regions of the P elements at 1A shows that in all cases these elements are flanked by Telomeric Associated Sequences, tandemly repetitive noncoding sequences that have properties of heterochromatin. In addition, we show that the regulatory properties of P elements at 1A can be inhibited by some of the mutant alleles of the Su(var)205 gene and by a deficiency of this gene. However, the regulatory properties of reference P strains (Harwich and Texas 007) are not impaired by Su(var)205 mutations. Su(var)205 encodes Heterochromatin Protein 1 (HP1). These results suggest that the HP1 dosage effect on the P element properties is sitedependent and could involve the structure of the chromatin.

scholarly journals A molecular characterization ofClostridium difficileisolates from humans, animals and their environments

1993 ◽  
Vol 111 (2) ◽  
pp. 257-264 ◽  
Author(s):  
G. O'Neill ◽  
J. E. Adams ◽  
R. A. Bowman ◽  
T. V. Riley
Keyword(s):  
Fragment Length Polymorphism ◽  
Hospital Environment ◽  
Enzyme Analysis ◽  
Restriction Enzyme Analysis ◽  
Direct Transmission ◽  
Chromosomal Dna ◽  
Veterinary Clinic ◽  
Enhanced Chemiluminescence ◽  
Typing Methods ◽  
Rflp Typing

SummaryIt is generally accepted that most patients withClostridium difficile-associated diarrhoea acquire the organism from the environment. Recently we demonstrated that household pets may constitute a significant reservoir ofC. difficilethrough gastrointestinal carriage in up to 39% of cats and dogs. These findings suggested that direct transmission from household pets, or contamination of the environment by them, may be a factor in the pathogenesis ofC. difficile-associated diarrhoea. To investigate this possibility, we examined isolates ofC. difficilefrom humans, pets and the environment by restriction enzyme analysis (REA) and restriction fragment length polymorphism (RFLP) typing using enhanced chemiluminescence. Both REA and RFLP typing methods usedHindIII digests of chromosomal DNA. A total of 116 isolates ofC. difficilefrom pets (26), veterinary clinic environmental sites (33), humans (37) and hospital environmental sites (20) was examined. REA was far more discriminatory than RFLP typing and for all isolates there were 34 REA types versus 6 RFLP types. There was good correlation between the REA types found in isolates from pets and from the veterinary clinic environment, and between isolates from humans and from those found in the hospital environment. There was, however, no correlation between REA type ofC. difficilefound in pets and isolates of human origin. We conclude that there may still be a risk of humans acquiringC. difficilefrom domestic pets as these findings may be the result of geographical variation.

scholarly journals Specific Detection of Xanthomonas axonopodis pv. dieffenbachiae in Anthurium (Anthurium andreanum) Tissues by Nested PCR

2006 ◽  
Vol 72 (2) ◽  
pp. 1072-1078 ◽  
Author(s):  
Isabelle Robène-Soustrade ◽  
Philippe Laurent ◽  
Lionel Gagnevin ◽  
Emmanuel Jouen ◽  
Olivier Pruvost
Keyword(s):  
Diagnostic Tool ◽  
Nested Pcr ◽  
Restriction Analysis ◽  
Detection Threshold ◽  
Enzyme Analysis ◽  
Restriction Enzyme Analysis ◽  
Amplification Product ◽  
Xanthomonas Axonopodis ◽  
Sequence Characterized Amplified Region ◽  
Pcr Test

ABSTRACT Efficient control of Xanthomonas axonopodis pv. dieffenbachiae, the causal agent of anthurium bacterial blight, requires a sensitive and reliable diagnostic tool. A nested PCR test was developed from a sequence-characterized amplified region marker identified by randomly amplified polymorphic DNA PCR for the detection of X. axonopodis pv. dieffenbachiae. Serological and pathogenicity tests were performed concurrently with the nested PCR test with a large collection of X. axonopodis pv. dieffenbachiae strains that were isolated worldwide and are pathogenic to anthurium and/or other aroids. The internal primer pair directed amplification of the expected product (785 bp) for all 70 X. axonopodis pv. dieffenbachiae strains pathogenic to anthurium tested and for isolates originating from syngonium and not pathogenic to anthurium. This finding is consistent with previous studies which indicated that there is a high level of relatedness between strains from anthurium and strains from syngonium. Strains originating from the two host genera can be distinguished by restriction analysis of the amplification product. No amplification product was obtained with 98 strains of unrelated phytopathogenic bacteria or saprophytic bacteria from the anthurium phyllosphere, except for a weak signal obtained for one X. axonopodis pv. allii strain. Nevertheless, restriction enzyme analysis permitted the two pathovars to be distinguished. The detection threshold obtained with pure cultures or plant extracts (103 CFU ml−1) allowed detection of the pathogen from symptomless contaminated plants. This test could be a useful diagnostic tool for screening propagation stock plant material and for monitoring international movement of X. axonopodis pv. dieffenbachiae.

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