The dynamics of the roo transposable element in mutation-accumulation lines and segregating populations of Drosophila melanogaster.
We estimated the number of copies for the long terminal repeat (LTR) retrotransposable element roo in a set of long-standing Drosophila melanogaster mutation-accumulation full-sib lines and in two large laboratory populations maintained with effective population size approximately 500, all of them derived from the same isogenic origin. Estimates were based on real-time quantitative PCR and in situ hybridization. Considering previous estimates of roo copy numbers obtained at earlier stages of the experiment, the results imply a strong acceleration of the insertion rate in the accumulation lines. The detected acceleration is consistent with a model where only one (maybe a few) of the approximately 70 roo copies in the ancestral isogenic genome was active and each active copy caused new insertions with a relatively high rate ( approximately 10(-2)), with new inserts being active copies themselves. In the two laboratory populations, however, a stabilized copy number or no accelerated insertion was found. Our estimate of the average deleterious viability effects per accumulated insert [E(s) < 0.003] is too small to account for the latter finding, and we discuss the mechanisms that could contain copy number.
Papaceit
Montserrat
M
Departamento de Genética, Facultad de Biología, Universidad de Barcelona, 08028 Barcelona, Spain.
Avila
Victoria
V
Aguadé
Montserrat
M
García-Dorado
Aurora
A
D000818:Animals; D000830:Animals, Laboratory / Q000235:genetics*; D002875:Chromosomes / Q000235:genetics; D004251:DNA Transposable Elements / Q000235:genetics*; D004331:Drosophila melanogaster / Q000235:genetics*; D005260:Female; D018628:Gene Dosage; D016678:Genome; D017403:In Situ Hybridization; D008297:Male; D009154:Mutation / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012641:Selection, Genetic; D020079:Terminal Repeat Sequences
D004251:DNA Transposable Elements