Genetics, Vol. 177, 511-522, September 2007, Copyright © 2007
doi:10.1534/genetics.107.076174

The Dynamics of the roo Transposable Element In Mutation-Accumulation Lines and Segregating Populations of Drosophila melanogaster

Montserrat Papaceit*, Victoria Ávila{dagger}, Montserrat Aguadé* and Aurora García-Dorado{dagger},1

* Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, 08028 Barcelona, Spain and {dagger} Departamento de Genética, Facultad de Biología, Universidad Complutense de Madrid, 28040 Madrid, Spain

1 Corresponding author: Departamento de Genética, Facultad de Biología, Universidad Complutense, 28040 Madrid, Spain.
E-mail: augardo{at}bio.ucm.es

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 ~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 ~70 roo copies in the ancestral isogenic genome was active and each active copy caused new insertions with a relatively high rate (~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.


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Genetics 2007 177: NP. [Full Text]