Genetic recombination and directional selection for DDT resistance in Drosophila melanogaster

Nature ◽  
1982 ◽  
Vol 298 (5875) ◽  
pp. 672-674 ◽  
Author(s):  
Phillip B. Flexon ◽  
Charles F. Rodell
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Recombination ◽  
Directional Selection ◽  
Ddt Resistance ◽  
Selection For

scholarly journals Recombination load associated with selection for increased recombination

1996 ◽  
Vol 67 (1) ◽  
pp. 27-41 ◽  
Author(s):  
B. Charlesworth ◽  
N. H. Barton
Keyword(s):  
Transposable Elements ◽  
Direct Effect ◽  
Quantitative Traits ◽  
Genetic Variance ◽  
Genetic Recombination ◽  
Additive Genetic Variance ◽  
Directional Selection ◽  
Additive Variance ◽  
Linkage Disequilibria ◽  
Selection For

SummaryExperiments on Drosophila suggest that genetic recombination may result in lowered fitness of progeny (a ‘recombination load’). This has been interpreted as evidence either for a direct effect of recombination on fitness, or for the maintenance of linkage disequilibria by epistatic selection. Here we show that such a recombination load is to be expected even if selection favours increased genetic recombination. This is because of the fact that, although a modifier may suffer an immediate loss of fitness if it increases recombination, it eventually becomes associated with a higher additive genetic variance in fitness, which allows a faster response to directionselection. This argument applies to mutation-selection balance with synergistic epistasis, directional selection on quantitative traits, and ectopic exchange among transposable elements. Further experiments are needed to determine whether the selection against recombination due to trie immediate load is outweighed by the increased additive variance in fitness produced by recombination.

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.

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