Behaviour of the transposable elements copia and mdg1 in hybrids between the sibling species Drosophila melanogaster and D. simulans

Abstract

The behaviour of the retrotransposons copia and mdgl was analysed in hybrids between Drosophila melanogaster and D. simulans. Females of a highly inbred line of D. melanogaster were crossed with D. simulans males from three natural populations. The insertion site profiles for the two elements were determined in F1 hybrid larvae by in situ hybridization to polytene chromosomes, and were compared with that of their parents. No somatic transposition events were detected after this genomic stress of interspecific hybridization for the two transposable elements concerned.

Hybridization and genome size evolution: timing and magnitude of nuclear DNA content increases in Helianthus homoploid hybrid species

“…We are currently seeking seed sources to establish whether the increases seen in the Helianthus hybrid species are exceptional. Evidence from some animal hybridization studies indicates that large changes in genome size can occur in a single generation through transposon replication (O’Neill et al ., 1998; Labrador et al ., 1999), although other animal and most plant studies have failed to find similar patterns (Guerreiro, 1996; Rayburn et al ., 1993; Williams et al ., 2002). Given the repeated independent emergence of larger genomes in hybrid sunflower taxa, we expected to see frequent increases in genome size in F 1 hybrids.…”

“…Similar patterns have been reported from studies of diploid hybrids. Some plant and animal hybrids show genomic changes upon hybridization, including fruit flies, wallabies, and beans (Rogers & Bendich, 1987; Petrov et al ., 1995; O’Neill et al ., 1998; Labrador et al ., 1999), whereas others are entirely stable (Guerreiro, 1996).…”