A simulation of P element horizontal transfer in Drosophila

Author(s):  
Hadi Quesneville ◽  
Dominique Anxolabéhère
Genetics ◽  
1990 ◽  
Vol 124 (2) ◽  
pp. 339-355 ◽  
Author(s):  
S B Daniels ◽  
K R Peterson ◽  
L D Strausbaugh ◽  
M G Kidwell ◽  
A Chovnick

Abstract Several studies have suggested that P elements have rapidly spread through natural populations of Drosophila melanogaster within the last four decades. This observation, together with the observation that P elements are absent in the other species of the melanogaster subgroup, has lead to the suggestion that P elements may have entered the D. melanogaster genome by horizontal transmission from some more distantly related species. In an effort to identify the potential donor in the horizontal transfer event, we have undertaken an extensive survey of the genus Drosophila using Southern blot analysis. The results showed that P-homologous sequences are essentially confined to the subgenus Sophophora. The strongest P hybridization occurs in species from the closely related willistoni group. A wild-derived strain of D. willistoni was subsequently selected for a more comprehensive molecular examination. As part of the analysis, a complete P element was cloned and sequenced from this line. Its nucleotide sequence was found to be identical to the D. melanogaster canonical P, with the exception of a single base substitution at position 32. When the cloned element was injected into D. melanogaster embryos, it was able to both promote transposition of a coinjected marked transposon and induce singed-weak mutability, thus demonstrating its ability to function as an autonomous element. The results of this study suggest that D. willistoni may have served as the donor species in the horizontal transfer of P elements to D. melanogaster.


2009 ◽  
Vol 81 (4) ◽  
pp. 679-689 ◽  
Author(s):  
Monica L. Blauth ◽  
Rafaela V. Bruno ◽  
Eliana Abdelhay ◽  
Elgion L.S. Loreto ◽  
Vera L.S. Valente

The P element is one of the most thoroughly studied transposable elements (TE). Its mobilization causes the hybrid dysgenesis that was first described in Drosophila melanogaster. While studies of the P element have mainly been done in D. melanogaster, it is believed that Drosophila willistoni was the original host species of this TE and that P was transposed to the D. melanogaster genome by horizontal transfer. Our study sought to compare the transcriptional behavior of the P element in embryos of D. melanogaster, which is a recent host, with embryos of two strains of D. willistoni, a species that has contained the P element for a longer time. In both species, potential transcripts of transposase, the enzyme responsible for the TE mobilization, were detected, as were transcripts of the 66-kDa repressor, truncated and antisense sequences, which can have the ability to prevent TEs mobilization. The truncated transcripts reveal the truncated P elements present in the genome strains and whose number seems to be related to the invasion time of the genome by the TE. No qualitative differences in antisense transcripts were observed among the strains, even in the D. willistoni strain with the highest frequency of heterochromatic P elements.


2000 ◽  
Vol 41 (4-5) ◽  
pp. 503-508 ◽  
Author(s):  
R.F. Gonçalves ◽  
F. Rogalla

This work describes laboratory scale research about Enhanced Biological Phosphorus Removal (EBPR) in a submerged biofilter under Anaerobic/Oxic (A/O) alternation and continuous feed. Its main purpose is to detail the behaviour of the reactor throughout the anaerobic and the aerobic phases of the A/O cycle, to study the importance of the anaerobic phase in the selection of the EBPR bacteria in the biofilm and to evaluate the consumption and the importance of the organic substrate during the anaerobic phase. The mass balance over the Phosphorus (P) element indicates that long anaerobic phases (6 h) are more efficient than short ones (3 h) as a selector of EBPR bacteria in biofilms. In both comparisons, thespecific mass of P released in a 6 h period represents almost 50% more than the amount of P release in the shorter period (3 h). However, the presence of rapidly biodegradable COD in the influent of the anaerobic phase is a more effective selector, more important than the duration of the anaerobic phase: by doubling the amount of acetic acid in the influent, a similar 50% increase of P-release can be achieved at short anaerobic periods of 3 h. The effect of the strategy adopted in this study, focusing on selecting EBPR bacteria in biofilm, is shown by the P levels of 4% (total P/SST) in the sludge removed from the BF by backwashing in all periods.


2021 ◽  
Author(s):  
Yaohui Wang ◽  
Xia Xu ◽  
Xi’en Chen ◽  
Xiaowei Li ◽  
Honglun Bi ◽  
...  

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