dynamics of the roo transposable element in mutation-accumulation lines and segregating populations of Drosophila melanogaster

• Published in: Genetics (Austin) Vol. 177; no. 1; pp. 511 - 522
• Main Authors: Papaceit, M, Avila, V, Aguade, M, Garcia-Dorado, A
• Format: Journal Article
• Language: English
• Published: United States Genetics Soc America 01-09-2007; Genetics Society of America; Copyright © 2007 by the Genetics Society of America
• Subjects: Animals; Animals, Laboratory - genetics; Chromosomes - genetics; DNA Transposable Elements - genetics; Drosophila melanogaster; Drosophila melanogaster - genetics; Female; Gene Dosage; Genetics; Genome; In Situ Hybridization; Investigations; Male; Mutation; Mutation - genetics; Polymerase Chain Reaction; Population; retransposon copy number; retrotransposons; Selection, Genetic; Terminal Repeat Sequences; transposition (genetics)
• ISSN: 0016-6731; 1943-2631; 1943-2631
• DOI: 10.1534/genetics.107.076174

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.