scholarly journals Direct determination of retrotransposon transposition rates in Drosophila melanogaster

1994 ◽  
Vol 63 (2) ◽  
pp. 139-144 ◽  
Author(s):  
Sergey V. Nuzhdin ◽  
Trudy F. C. Mackay
Keyword(s):  
Drosophila Melanogaster ◽  
Transposable Element ◽  
Inbred Line ◽  
Copy Number ◽  
Direct Determination ◽  
Hybridization Analysis ◽  
Spontaneous Mutations ◽  
Insertion Sites

SummaryRates of transposition and excision of the Drosophila melanogaster retrotransposon elements mdg3, 297, Doc, roo and copia were estimated directly, by in situ hybridization analysis of their cytological insertion sites in 31 replicates of a highly inbred line that had accumulated spontaneous mutations for approximately 160generations. Estimated transposition rates of Doc, roo and copia were, respectively, 4·2 × 10−5, 3·1 × 10−3 and 1·3 − 10−3; no transpositions of 297 nor mdg3 were observed. Rates of transposition of copia varied significantly among sublines. Excisions were only observed for roo elements, at a rate of 9·0 × 10−6 per element per generation. Copy number averaged over these element families increased 5·9 %; therefore, in these lines the magnitude of the forces opposing transposable element multiplication were weaker than transposition rates.

Bohrwiderstandsmessungen, eine neue und standardisierbare Methode zur Bestimmung der Kohäsion von Naturstein: Entwicklung eines Prototypes und dessen Erprobung / Drilling force measurement system, a new standardisa i methodology to determine the stone cohesion: Prototype design and validation

2000 ◽  
Vol 6 (2) ◽  
pp. 115-132 ◽  
Author(s):  
P. Tiano ◽  
C. Filareto ◽  
S. Ponticelli ◽  
M. Ferrari ◽  
E. Valentini
Keyword(s):  
Force Measurement ◽  
Direct Determination ◽  
Drilling Force ◽  
System A ◽  
Stone Materials ◽  
Force Measurement System ◽  
Drilling Resistance ◽  
Non Destructive

Abstract In the field of conservation of monumental buildings actually a standard methodology is lacking, with which it is possible to determine with the same sensitivity and reliability the "stone hardness" both at the superficial surface and at larger depths (few centimetres), both in laboratory and in situ. The use of the drilling resistance to determine the stone hardness is a very recent application and few working outdoor devices exist. The objective of this work is to validate a new and improved system to assess the drilling resistance of stones. The DFMS is portable and a quasi non-destructive device for direct determination of the "cohesion" of stone materials through the determination of their drilling resistance. The best operational features of the prototype have been established together with the assessment of the sensitivity and reliability of the system.

scholarly journals The distribution of transposable elements within and between chromosomes in a population of Drosophila melanogaster. I. Element frequencies and distribution

1992 ◽  
Vol 60 (2) ◽  
pp. 103-114 ◽  
Author(s):  
Brian Charlesworth ◽  
Angela Lapid ◽  
Darlene Canada
Keyword(s):  
Population Dynamics ◽  
Drosophila Melanogaster ◽  
Linkage Disequilibrium ◽  
Transposable Elements ◽  
Copy Number ◽  
Polytene Chromosomes ◽  
Chromosome Band ◽  
High Frequencies ◽  
Copy Numbers

SummaryData were collected on the distribution of nine families of transposable elements among second and third chromosomes isolated from a natural population of Drosophila melanogaster, by means of in situ hybridization of element probes to polytene chromosomes. It was found that the copy numbers per chromosome in the distal sections of the chromosome arms followed a Poisson distribution. Elements appeared to be distributed randomly along the distal sections of the chromosome arms. There was no evidence for linkage disequilibrium in the distal sections of the chromosomes, but some significant disequilibrium was detected in proximal regions. There were many significant correlations between different element families with respect to the identity of the sites that were occupied in the sample. There were also significant correlations between families with respect to sites at which elements achieved relatively high frequencies. Element frequencies per chromosome band were generally low in the distal sections, but were higher proximally. These results are discussed in the light of models of the population dynamics of transposable elements. It is concluded that they provide strong evidence for the operation of a force or forces opposing transpositional increase in copy number. The data suggest that the rate of transposition perelement per generation is of the order of 10−4, for the elements included in this study.

Direct speciation of Cr in drinking water by in situ thermal separation ETAAS

2017 ◽  
Vol 9 (8) ◽  
pp. 1307-1312 ◽  
Author(s):  
Hao Cui ◽  
Wei Guo ◽  
Lanlan Jin ◽  
Qinghai Guo ◽  
Shenghong Hu
Keyword(s):  
Drinking Water ◽  
Direct Determination

Evaluation of anin situthermal separation ETAAS method for the direct determination of Cr species was carried out.

scholarly journals Transmission pattern of hobo transposable element in transgenic lines of Drosophila melanogaster

1998 ◽  
Vol 71 (2) ◽  
pp. 97-107 ◽  
Author(s):  
VERONIQUE LADEVEZE ◽  
IBO GALINDO ◽  
NICOLE CHAMINADE ◽  
LUIS PASCUAL ◽  
GEORGES PERIQUET ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Population Studies ◽  
Insertion Site ◽  
Molecular Analyses ◽  
Transgenic Lines ◽  
Genomic Dnas ◽  
Insertion Sites ◽  
Method Show

This study is an attempt to trace the fate of hobo elements in the genomes of E strains of Drosophila melanogaster that have been transfected with pHFL1, a plasmid containing an autonomous hobo. Such long-term population studies (over 105 generations) could be very useful for better understanding the population and genomic dynamics of transposable elements and their pattern of insertions. Molecular analyses of hobo elements in the transfected lines were performed using Southern blots of XhoI-digested genomic DNAs. The complete element was observed in all six injected lines. In two lines we observed, at generation 100, two deleted elements, which did not correspond to Th1 and Th2. The results obtained by the in situ method show that the number of hybridization sites increases in each line and prove that the hobo element may be amplified in an RM genome. The hobo activity does not seem to be systematically correlated with the number of hobo elements. After generation 85, the evolution of the hobo element's insertion site number depends on the injected line. In all lines, the total number of insertions remains quite small, between 0 and 11. Hobo elements are located on each of the chromosomal arms. We describe ‘hotspots’ – insertion sites present in all lines and in all generations. On the 3R arm, a short inversion appeared once at generation 85.

Sign in / Sign up

Export Citation Format

Share Document