# name
Distribution of the transposable elements bilbo and gypsy in original and colonizing populations of Drosophila subobscura

# metadata.dc.description.abstract[].value
Background: Transposable elements (TEs) constitute a substantial amount of all eukaryotic genomes. They induce an important proportion of deleterious mutations by insertion into genes or gene regulatory regions. However, their mutational capabilities are not always adverse but can contribute to the genetic diversity and evolution of organisms. Knowledge of their distribution and activity in the genomes of populations under different environmental and demographic regimes, is important to understand their role in species evolution. In this work we study the chromosomal
distribution of two TEs, gypsy and bilbo, in original and colonizing populations of Drosophila
subobscura to reveal the putative effect of colonization on their insertion profile.
Results: Chromosomal frequency distribution of two TEs in one original and three colonizing
populations of D. subobscura, is different. Whereas the original population shows a low insertion
frequency in most TE sites, colonizing populations have a mixture of high (frequency ¿ 10%) and
low insertion sites for both TEs. Most highly occupied sites are coincident among colonizing
populations and some of them are correlated to chromosomal arrangements. Comparisons of TE
copy number between the X chromosome and autosomes show that gypsy occupancy seems to be
controlled by negative selection, but bilbo one does not. Conclusion: These results are in accordance that TEs in Drosophila subobscura colonizing populations are submitted to a founder effect followed by genetic drift as a consequence of colonization. This would explain the high insertion frequencies of bilbo and gypsy in coincident sites of colonizing populations. High occupancy sites would represent insertion events prior to colonization. Sites of low frequency would be insertions that occurred after colonization and/or
copies from the original population whose frequency is decreasing in colonizing populations. This
work is a pioneer attempt to explain the chromosomal distribution of TEs in a colonizing species
with high inversion polymorphism to reveal the putative effect of arrangements in TE insertion
profiles. In general no associations between arrangements and TE have been found, except in a few
cases where the association is very strong. Alternatively, founder drift effects, seem to play a
leading role in TE genome distribution in colonizing populations.

# metadata.dc.relation.ispartof[].value
Bmc Evolutionary Biology, 2008, vol. 8, núm. 234

# metadata.dc.rights[].value
cc-by, (c) García Guerreiro et al., any publicació

# metadata.dc.source[].value
Articles publicats en revistes (Genètica, Microbiologia i Estadística)

# metadata.dc.title[].value
Distribution of the transposable elements bilbo and gypsy in original and colonizing populations of Drosophila subobscura